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Scientific diving

Scientific diving is the use of diving techniques by scientists to study underwater what would normally be studied by scientists on land. Scientific divers are normally qualified scientists first and divers second, who use diving equipment and techniques as their way to get to the location of their fieldwork. Underwater archeology, marine biology and geology are examples of sciences pursued underwater. Some scientific diving is carried out by universities in support of undergraduate or postgraduate research programs.

Government bodies such as the United States Environmental Protection Agency and the UK Environment Agency carry out scientific diving to recover samples of water, marine organisms and sea, lake or riverbed material to examine for signs of pollution.

Equipment used varies widely in this field, but surface supplied equipment though quite uncommon in the UK is growing in popularity in the U.S. The short number of dives made by scientific divers in normally quite shallow water, and the UK governmental regulations that make surface supplied equipment cumbersome, when combined with a need for easy transportation make surface supplied gear uneconomic and undesirable for UK scientists to use.

The two standard references for Scientific Diving Operations are:

Flemming, N. C., Ed.; Max, M. D. (Ed) Code of Practice for Scientific Diving: Principles for the Safe Practice of Scientific Diving in Different Environments. UNESCO Technical Papers in Marine Science 53.

Joiner James T. (ed), NOAA Diving Manual: Diving for Science and Technology, Fourth Edition, 2001, U.S.Department of Commerce, National Technical Information Service, (ISBN 0941332705)

wikipedia.org

Artificial Reefs for Marine Life

Things sink. Everyone knows that. The bottom of the ocean is covered in things that have sunk throughout history. But sometimes people decide to sink things on purpose to create an artificial reef. It could be a few cinder blocks, tires, movie sets, an old freight container, or an entire train. Whatever is sunk, it is sunk with the purpose of promoting marine life.

Artificial reefs can be made in any coastal waters. When an artificial reef is sunk, it makes a great location for species like algae, barnacles, corals, and oysters to attach and make a new home. Over time a lively reef forms and provides great fishing locations, idyllic scuba diving sites, and superb marine habitats.

Unfortunately around the world coral reefs are suffering. Global warming, over fishing, pollution, rising sea level, inexperienced divers, and much more are quickly killing the ecologically fragile and diverse reefs. Artificial reefs are a good way to help these abused reefs regenerate because they relieve stress from reefs that are overwhelmed by human and sea life impact. Someday those abused reefs may thrive again.

Artificial reefs help attract divers away from the fragile ecosystems of natural coral reefs by providing them with new alternative reefs to explore. Artificial reefs are often created on shipwrecks; a type of diving that already is alluring for most divers. In fact, many old Naval ships, after they are decommissioned, are now being sunk to create artificial reefs and promote marine life. It’s actually more politically, environmentally, and economically cheaper to do this than take the ships apart for scraps.

The U.S. Environmental Protection Agency, even gives guidelines on how to prepare your boat, car, or plane if you want to sink it and make an artificial reef. Several privately owned companies are creating jobs specifically for this niche market.

Artificial reefs are great way to promote aquatic life, but as with everything there are always people who oppose new ideas. The naysayers feel there is no major marine life benefit and that artificial reefs only pollute the ocean.

So next time you’re enjoying diving on a sunken James Bond plane wreck in the Bahamas, a sunken train in Thailand, or an underwater tire world in Florida, remember they aren’t natural reefs but they’re awesome diving.

scientificdiving.net

Benthic Ecology

The oceans cover 72% of the earth’s surface. And under every square mile of water there is a square mile of sea floor. The sea floor is a huge place that is mostly unexplored. Benthic ecology studies the organisms that live in, on, and around the sea floor and how they impact the environment. It’s an intricate science that reveals much about marine environments.

Benthic ecology is the study of the entire sea floor. It can be broken down into two forms – shallow water benthic ecology and deep-sea benthic ecology. Shallow water benthic ecology examines things like the effects of pollution on clam species and how water flow affects species distribution. Deep-sea benthic ecology is exploring the organisms that live near thermal vents and the isolated coral communities that live deep in the ocean’s abyss.

There are several big questions that benthic ecology scientists want to answer. Why do some sea floor areas thrive while other areas lack activity? What are the long-term effects of climate change on the sea floor ecosystem? How do invasive species influence the native plants and animals? How does competition change the range of species in an area? How do deep-sea creatures exist in such extreme conditions? These are all fascinating topics that make scientists and underwater enthusiasts giddy with excitement.

Many leading underwater scientific organizations are currently studying benthic ecology. Both the Woods Hole Oceanographic and the Smithsonian Environmental Research Center are observing and collecting data on the communities and populations of bottom dwelling species. For over 37 years, leading scientists and representatives have attended the Benthic Ecology Meeting to share new research, findings, and publications.

Benthic ecology research teaches us how nutrients are recycled, how marine food webs exist, what organisms can be beneficial to humans, and what the impact of non-native species does to the ecosystem. It is a significant area of study that needs our focus.

From marshes and wetlands to coral reefs and deep seamounts, benthic ecology is an important science that scientists from around the world study. The sea floor is an active place where organisms live and interact. With proper research and attention, benthic ecology will yield plenty of exciting discoveries in the years to come.

scientificdiving.net

Biodiversity in the Underwater World

Every year hundreds of thousands of people go diving on coral reefs around the world. It’s an indescribable experience. There are countless fish, tall corals, colorful algae, and other creatures and plants that are new and foreign to you. It’s amazing. Spending just a few hours engaged on a coral reef will have you hooked for life. It’s like you’ve visited another world and usually the only reason you leave is because your tank is getting low.

When you visit that underwater world, it’s impressive. There are so many different species in one place. And every reef around the world is different. This is called biodiversity. Merriam-Webster Dictionary defines biodiversity as biological diversity in an environment as indicated by numbers of different species of plants and animals.

No one knows how many reefs there are under our seas, but there are a lot. Every reef in every ocean is a unique eco-system. Look at a reef in the Indian Ocean versus a reef in the South Pacific or Caribbean. You’ll see completely different species. This biodiversity has been created by evolution and isolation. For nearly 4 billion years, nature has evolved into what it is today. In that time, species have come, gone, and adapted to their surroundings. It’s how the world works.

Scientists are interested in the biodiversity of the ocean because biodiversity helps measure how healthy a location is. If lots of species coexist in one place, it’s healthy. If an eco-system is dull and only a few species thrive, it’s not doing very well.

Science diving explores the biodiversity of the underwater world. By looking at things such as the numbers of hard and soft corals, sponges, mollusks, crustaceans, and fish, they can understand how a reef works. In order to protect theses species they need to learn how things like a rising sea level, coral bleaching, non-native species, and pollution affect biodiversity.

The world needs to maintain the biodiversity that still exists. In areas of the South Pacific there are bays with more species than the entire Caribbean. We need to protect the species and eco-systems that are left. By researching and studying the underwater world, science can help learn about and preserve the world’s remaining coral reefs.

scientificdiving.net

Near Shore Ecology

According to the CIA’s World Fact Book, there are 356,000 kilometers of ocean coastline in the world and there is a lot of marine life that lives near the coast. Near shore ecology can be described as the area that begins at the low water mark and goes well beyond the surf. It usually ranges from the coastline to about 30 meters deep. Near shore ecology includes diverse areas that support a huge number of different plants, fish, and wildlife. It is an ecosystem that is directly affected by human impact. The coast thrives on tourism and business, but it is also a delicate ecosystem that needs to be protected. Near shore ecology is affected by everything we do - pollution, fishing, shoreline stabilization, development. All of our actions change the dynamics of marine habitats and populations. Our impact is greater than we may realize. It is important for scientists to study this interaction in order to learn how to preserve and protect the native species and habitats of the near shore ecosystem. Through the study of physical, chemical, geological, and biological aspects scientists can begin to understand this complex ecosystem. The physical components of the near shore ecosystem are called controlling factors and consist of things such as wave energy, temperature, salinity, nutrients, light, slope, depth, and water quality. When one of these controlling factors is affected, it changes the habitat structure of the ecosystem, which in turn changes the way the underwater habitats function. When this happens the ecological functions are altered and the entire near shore ecosystem is transformed. It may sound a little confusing, so here’s an example – the creation of an artificial reef can change the energy produced by waves. This kills off a certain species of plants that was food for a specific type of fish. That fish then is forced to migrate to another region of the underwater world to survive. This is just one example. There are countless things that affect the fragile coastal ecosystem and the more we know, the more prepared we can be to protect it. Through research, observations, and data collection scientists can learn how the near shore ecology is changing and take steps to conserve the delicate ecosystem.

scientificdiving.net

Phycology in the Aquatic Ecosystem

Did you know that there are nearly 30,000 species of algae? Algae play a very important role in the aquatic ecosystem. They are the primary producers of oxygen. They lack roots, stems, and leaves and range from single celled microscopic organisms like phytoplankton to multicellular larger organisms like seaweeds. The reason we know about algae is because scientists, called phycologists, study algae in marine and freshwater environments around the world.

Phycology, or the study of algae, is one of the most important sciences. It can be traced back over two thousand years, with rapid development in the science in the past 300 years. Humans are interested in algae because of its plant-like qualities. It is now categorized as a subset of botany, the study of plants. It has even been dubbed one of the world’s most important organisms.

Algae are amazing. They can survive in the most extreme conditions. Scientists have found algae in deserts, boiling springs, ice, and snow. They survive off the simple process of photosynthesis, where they use energy from the sun to create simple sugars and give off oxygen. Oxygen allows other species, like fish to breathe underwater. Algae are the key to the underwater food chain. But algae are more than just an underwater oxygen producer. It is also estimated that algae produces 70% to 80% of all the oxygen in the atmosphere. Without algae humans, along with other animals, wouldn’t exist.

As you can tell algae is critical to the world. Scientists have discovered three types of algae – red, green, and brown. Red algae live in the deep tropical and temperate waters. Brown algae, the most abundant in the ocean, are small and drift with the currents. Green algae are the type you might recognize on lakes and ponds. Scientists study algae all over the world. Algae can live as deep as 300 feet, so one way to observe and gather algae data is by diving. Often they are so small they cannot be seen with the naked eye.

The only way to truly see these incredible organisms is by microscope.

Algae have multiple other uses besides just being oxygen producers and food chain members. Algae are used to keep paint smooth, thicken ice cream, fight cancer, and cure coughs. And science may discover other important uses in the future. So next time you see that “green scum” on your local pond, you will know that that slime is one of the big reasons that you can both breath and enjoy ice cream.

scientificdiving.net

Scientific Diving Equipment

Diving is very equipment intensive and scientific diving can take it to a whole new level. Whenever you are diving you are visiting another world. You have to completely rely on your equipment to survive. It is critical that you understand how your equipment functions. It doesn’t take much to cause an untimely accident.

Scientific divers pack their diving gear bag with all the same things a recreational diver uses. They need a wetsuit or a dry suit depending on the temperature of the water. They have a mask and a snorkel to see underwater. A buoyancy control device (BCD) helps divers maneuver through the water and float on the surface. An air delivery system with both primary and backup regulators allow the diver to breathe underwater. A knife is important in case you get tangled in kelp or snagged on a rope or fishing line. They may have a flashlight to see the true colors of the underwater world. Fins help them move through the water. A computer can calculate their air usage, bottom time, depth, and decompression stops. These are the basics that every diver should have.

Now scientific divers often need more equipment than the average recreational diver. It all depends on what scientific purpose they are pursuing. A diver traveling hundreds of feet deep to study a newly discovered form of algae will need different air mixes of nitrox or trimix. They also may need additional tanks of air to allow them to stay down longer or to account for decompression stops. A scientific diver in polluted water may want a full-face mask to keep pollution off of his skin. If a diver is venturing into caves or wrecks he will want a wreck reel and multiple flashlights. A team exploring coral reefs may want a camera to capture the movements and marine life’s activities.

Some divers may want a recall unit that sends out tonal messages to other team members. Divers that are studying a large area may use a DPV, or diver propulsion vehicle to help them travel faster than their fins can kick. Mapping equipment can help with underwater surveying. Rebreathers can be used to eliminate bubbles if bubbles disturb the environment. Scientists may need bottles, nets, jars or bags to take samples. Pencils and writing boards may be necessary to take notes. Rulers may be crucial to measure things.

Every scientific diving team will need different equipment. The things mentioned here do not cover everything that they may need. It all depends on what the team is studying. Whatever equipment a scientific diving team uses, they need to have training to ensure they know how to use and maintain the equipment in a safe manner.

scientificdiving.net

Underwater Ecosystems are Changing

Ecosystems are constantly changing and organisms are constantly adapting. It is the way the world works, since the beginning of time nature has ebbed and flowed. Earth has gone through warm periods and ice ages. Every time the environment changed, so did the ecosystems of the world. Organisms survive by adapting and evolving with the changes of nature.

Unfortunately, ecosystems are changing at an alarming rate. The change is coming so fast that organisms don’t have time to adapt to their new environments and instead of adaptation they are facing extinction. It’s a problem that needs to be researched so that we can help organisms survive and prosper. Scientists are always trying to discover new ways to conserve and protect the world’s ecosystems.

The underwater world is one of the fastest changing ecosystems. Nearly everything affects the natural underwater world. Over fishing, climate change, invasive species, human development, and pollution are just the start of a long list that affects the world’s seas.

It may be easiest to look at a simple example. When you drive a car, you pollute the air. The pollution adds to the hole in the ozone. The ozone hole drives global warming. Global warming melts the polar ice caps. The melted polar ice caps cause sea levels to rise. Rising sea levels change the amount of light that reaches coral reefs. Without enough light, coral reefs decline and slowly die out. Coral reefs act as homes to numerous animals that then have to migrate to new habitats. These new habitats become overwhelmed, food chains are disrupted, and so forth… It’s a vicious cycle that continually changes the ecosystem. This is just one example, but there are plenty of others.

Through research and collaboration, scientists are trying to learn the cause and effects of each step. With a bit of luck, their research about the underwater world and the interrelated processes of humans and the planet will help to protect and preserve the ocean’s ecosystems. It will give all species an opportunity to adapt to the ever-changing environment and survive long into the future.

scientificdiving.net

Underwater Research

There are so many things on this planet that have yet to be discovered. With 72% of the earth’s surface covered by water; a large majority of these remaining discoveries may exist underneath the veil of water. For hundreds of year, people have attempted to explore and research the underwater unknowns. On a whole they have been successful. Their research has unlocked theories on the origin of life, put seaweed in our toothpaste, and brought us the joy of coral reefs.

Underwater research is a broad spectrum of science. There are hundreds of different organizations, institutes, and universities that are members of the American Academy of Underwater Sciences. All of these groups are classified as scientific diving groups and they are researching the mysteries in the underwater world. Their research is very important and is helping answer questions about everything from phycology to global warming.

Scientists proudly research all sorts of underwater phenomena’s. Ocean Earth is monitoring coral reefs and exploring maritime archaeology. The University of California at Santa Cruz is busy measuring the physiological responses of diving mammals and the ecology of kelp forests. Woods Hole Oceanographic Institution is researching ocean geology and freshwater and saltwater chemical interactions. NOAA is studying the deep unexplored waters of the seas and the preservation of coral reefs. The Smithsonian Environmental Research Center studies benthic ecology and coastal food webs. Other research groups are studying amazing underwater things like whale migration patterns, underwater communications, sonar, polar ice caps, sea level variations, or diving safety.

Underwater research takes places all over the world. Scientific teams explore both fresh and salt water. Divers plunge into the seas in places like the polar regions of Antarctica, the tropical seas of the Caribbean, the murky depths of New England, and the vast lakes of the Andes. Underwater research is completed anywhere there is water – new discoveries often exist in places you would least expect. By exploring new places, monitoring conditions, observing, and collecting data, scientists are able to make scientific breakthroughs that have the potential to change the world.

All aspects of science that are covered on land are also covered under the sea – geology, biology, botany, physiology, chemistry, and many more. Underwater research is important because it will help us solve problems and understand the planet that we live on.

scientificdiving.net

Canon G11 & Canon G12 Underwater Photography Tutorial

Text by Stanley Bysshe, Photos by Stanley Bysshe, Carl Waxman and Steve Kletz

When you start your retirement by moving to a Caribbean island, friends tend to find you.

Two friends from the States who are also good diving buddies have wanted to upgrade their underwater photography equipment for a while.

So for the last six months they researched what to buy to replace their old Nikonos Vs. They chose not to house their digital SLRs and wanted an "easy travel system". I have to say I was a little envious when they got off the plane in sunny Curacao with camera, strobes, housing and accessories all in a neat carry on backpack.

The underwater system:

Camera: Canon G11. Everything in this article also applies to the Canon G12. Canon simply added 720hp video to the Canon G11, and a new control dial.

Dual Sea & Sea YS 110a strobes, fiber optic cables

Fix Fisheye G11 housing, now available as the Recsea Canon G11/G12 housing

Fisheye Wide angle conversion lens.

Fisheye easy close up wet mount diopters (2)

Ultralight Tray and arms.

The set up was fairly straightforward and we tested the systems that night in the pool to make sure everything was in working order and to try and learn the controls.

Wide Angle Port on the Canon G11.

photo taken with: Nikon D2x Tokina 10-17mm fisheye

Macro set up on the G11

photo: Nikon D2x Tokina 10-17mm

The G11 booklet was not particularly user friendly, but you could say that about a lot of camera instruction booklets. We chose for the settings to be completely based on manual controls. M2 (no pre flash) for the Ys 110s. The camera flash was set on its lowest power. Also when set on macro for close ups and using the diopters you do have to zoom in a little to avoid vignetting from the diopter frames. Further, when shooting with the dry mount wide angle port the camera should be set on macro.

In short my friends basically followed the shooting parameters set out in the UWPG article:http://www.uwphotographyguide.com/canon-s90-g11-underwater-settings

All shots were in RAW, and Auto white balance.

Wide angle: A Shutter Speed of 1/125th gave a nice blue to the water at 40 -60 feet. Adjust as needed to change the "blueness". F 5.6. Strobes were usually more to the full power end of the dial.

Macro: Shutter speed 1/250-1/500. F8 and adjust. Strobes at low power and work up as needed.

Spotted Coral Shrimp F8 1/1500th ISO 100 2 diopters

Iguana F4.5 1/80th ISO 100

Scorpion fish F8 1/500th ISO 100

Lettuce Sea Slug F8 1/500th ISO 100 2 diopters

Golden Tail Moray F8 1/500th ISO 100

After some twelve dives including night dives I think both friends were pleased with their choice of systems. As a side note they did have one flash that flooded but because of the well designed battery compartment the flash was easily rinsed, dried and immediately put back in service. It may not be a housed DSLR, but there is a lot of sophistication in the system. So expect a learning curve before really concentrating on photography.

Some observations from the sidelines:

1) Focusing seemed to be the biggest hassle, especially in macro. They tried Auto and Servo modes but never got really comfortable with the "live view" unless the subject was stationary or really slow moving. They did not try changing the screen focusing cursor to allow for more off center composition.

2) The wet macro diopters seemed a bit flimsy but gave pretty good results when accurate focusing was obtained. Watch out for vignetting.

3) The Wide angle port, I think gave very nice results. This has great potential.

4) The flash system worked very well and changing flash output quickly got to be second nature. Also, with dual strobes both guys readily saw the possibilities of creative lighting. However flash positioning takes practice and some thought for every shot. (True for all of us!)

5) The system has nice versatility. With the regular port you can work with fish, do some scenics and switch to macro, adding the diopters as needed.

6) Camera battery life seems unpredictable. If you do a lot of shooting change the battery after the dive, at least until you have some idea as to images per battery charge.

7) Practice on land before the big trip so you feel comfortable with the camera menu and settings. All we did was dive and photograph so this was on the job learning.

8) If you are just starting your digital photography "career" don't forget the post processing aspect of your new system. What are you going to do with all those RAW files? How will you manage your images on vacation and protect your best shots?

I have seen some great Canon G11 & Canon G12 shots in the forums and with practice a system based around this camera should allow you to post some excellent images.

from.uwphotographyguide.com

Underwater Camera Maintenance

By Jeff Mullins Maintenance is one of the duties that almost every underwater photographer wishes they didn’t have to do. However, it’s the very people that don’t do it that are the ones that will sooner or later suffer a problem with their equipment. If done correctly maintenance is just a minor inconvenience before or after a dive, but if ignored it can lead to a catastrophic flood. Housing floods, for those readers that haven’t suffered one yet, are what turns the most positive thinking underwater photographer, into a dribbling, incoherent state of depression. You’ve probably seen one of these flood victims on at least one of your previous dive trips. It’s that person sitting in the corner nursing a salty camera and mumbling about ‘O’ rings to anyone that comes within earshot. Everyone avoids that person, and with good reason; as the latest studies clearly show that camera floods are highly contagious. So what can you do to increase the life of your housing and minimize the chance of becoming another flood victim?

By following these simple maintenance steps you will go a long-way towards extending the life of your housing and preventing a lethal dose of this deadly disease. Housing Maintenance falls into three distinct categories: 1. Pre-Dive Maintenance involves small checks and cleaning prior to a dive. These are simple, easy to conduct procedures that are carried-out while you assemble your camera equipment. It will probably take between 1-5 minutes depending on the complexity of your equipment. 2. Post-Dive Maintenance is carried-out while stripping down your camera gear for storage, usually once you are at home, and will take between 5-10 minutes. 3. Long Term Maintenance is usually carried out annually or bi-annually and is best carried-out by the equipment manufacturer or their service agent.

Pre-Dive Maintenance

Post-Dive Maintenance is performed while you assemble your equipment before a dive. It’s preferable to do this at home or in your hotel room, not on a rocking and rolling dive boat or on a sandy beach. • If you are in a hot humid country, try to assemble your camera/housing in an air conditioned room, preferably with the camera removed from the housing overnight and the housing kept open overnight. This way both the camera and housing are in the driest (least humid) condition when being assembled. Don’t take the camera or housing outside until it’s fully assembled, as the camera will fog-up almost immediately upon exposure to the warmer/humid air outside of the air conditioned room. • If you are in a cooler/dryer climate, then assemble your camera & housing inside, away from dust and sand. • For most housings, the Main Body (rear door) ‘O’ Ring should already be removed from your housing (see Post Dive Maintenance below). If it isn’t, then remove it now for cleaning, prior to assembly.

Hold the ‘O’ Ring with your left hand and then by pushing with a tissue in your right hand, the ‘O’ Ring will generally then become loose in the groove.

once it has loosened enough, lift the ‘O’ Ring from its groove.

This is a close-up photo of the ‘O’ Ring in my friends housing after only one dive in a sandy area. This ‘O’ Ring has to be removed, cleaned and then re-lubed before using the housing.

• Clean the ‘O’ Ring groove in the housing rear door and in the front port (if fitted with a removable port) by wiping it with a piece of clean tissue paper, lens paper or microfiber cloth. Push the tissue into the groove, so it forms the square shape of the groove.

Clean the housing ‘O’ Ring groove with a clean tissue

Now, in one continuous motion, wipe around the entire groove until the entire circumference has been wiped.

Push the tissue firmly into the ‘O’ Ring groove in one continuous motion around the entire circumference

Remove the tissue and check for any pieces of tissue that may have remained in the groove. Also look for dust particles, hair, or any other foreign material that may interfere with the ‘O’ Ring sealing. • Give the ‘O’ ring (or ‘O’ rings if there are more than one) a wipe with another clean tissue. Don’t stretch the ‘O’ Ring, just wipe it to make sure no large particles, hairs or other foreign material are stuck to it.

Wrap the ‘O’ Ring in tissue and pull the ‘O’ Ring through the tissue. This wipes the ‘O’ Ring clean as it passes through the tissue.

Look what came off this particular ‘O’ Ring - lots of black sand!

• Apply a small amount of the ‘O’ ring grease supplied with your housing to the main body ‘O’ ring(s). Use just enough grease to make the ‘O’ ring(s) shiny – NOT so much that there are visible lumps of grease – It is possible to over-grease the O-ring!

Use the correct ‘O’ Ring grease supplied with your particular housing

At the same time you are applying the ‘O’ Ring grease, feel the ‘O’ Ring for nicks, cuts or sand particles. It’s amazing how much your fingers can feel when lubing the ‘O’ Ring. If you feel any imperfections, check them out with a magnifier before installing the ‘O’ Ring. If in doubt replace it first-- ‘O’ Rings are very cheap in comparison to flooded cameras or strobes! • Install the camera in the housing, checking that it is seated correctly. • If your camera set-up uses the camera’s internal flash for lighting or if it uses the camera’s internal flash to fire an external strobe, then you need to install a Desiccant Pack inside of the housing before closing it.

Dessicant Packs absorb moisture, they come in various shapes and sizes. Find a brand that fits easily into your housing.

This will save your camera from premature failure due to moisture forming inside the housing. When the internal strobe fires underwater it releases a lot of heat into the confined space of the housing. This heat causes moisture from the trapped air in the housing to condense on the camera and inside of the housing. The Desiccant Pack will help absorb most of this condensation. (The Desiccant Pack can later be heated in an oven to remove the condensation for re-use).

• Make sure the Desiccant Pack is not interfering with the ‘O’ ring sealing surface as you close the back of the housing. Also ensure that it is not stopping the camera from seating correctly in the housing, as this may stop the housing rear door from closing tightly.

Find a location where the Dessicant Pack does not interfere with your camera fitting into its housing, nor interferes with the ‘O’ Ring sealing correctly.

In this housing, the Dessicant Pack sits easily alongside the lens, the rubber surrounding holds the Dessicant Pack away from the actual lens.

With clear acrylic housings you can visually check that the ‘O’ Ring is seated correctly in the groove by looking through the side of the housing BEFORE entering the water. The ‘O’ Ring should contact the housing evenly over its entire circumference – it appears slightly darker where it is sealing. Most leaks are caused by the ‘O’ ring not being seated correctly or dirt in the ‘O’ ring groove.

• You are now ready to assemble strobes. These are treated the same way as the camera housing: clean the ‘O’ Ring groove, clean the ‘O’ Ring, lubricate the ‘O’ Ring lightly, and install the ‘O’ Ring. Install batteries, ensuring correct polarity (+ positive and – negative). Test that the strobe ready light is operating before connecting to the housing. • If you use external strobes you will now be fitting your base plate and strobe arms. Test fire the camera before entering the water, this ensures that everything is functioning correctly. • Now you are ready to enter the water. Keep an eye on the housing when first entering the water and descending. Most leaks occur within the first few meters and you may be able to save the camera if you see a leak early enough.

Post-Dive Maintenance

Post-Dive Maintenance is mostly carried out once you are back in your hotel room or in your boat cabin, or home. It isn’t carried-out on the rolling deck of a boat or on a beach. That said, there are some very basic things that should be done between dives and as soon as you are out of the water.

• Rinse your camera in fresh water upon surfacing from each dive. If there is no rinse tank on a boat, or you are shore diving with no rinse tank, bring along an old towel that can be dunked in the seawater. Then between dives, wrap your housing in the towel and keep it out of the sun in order to keep the housing cool and damp. This will prevent salt from drying-out and crystallizing on housing controls, which damages the ‘O’ Rings the next time you press a button and can cause a flood. • Make sure your camera equipment is not in the dive boat rinse tank along with Harry Heavy-Hand’s half-ton alloy housing with 4 strobes attached, squashing your pocket sized compact camera underneath it. Most dive boats have a Harry Heavy-Hands onboard! • When you are finished diving for the day, give your housing another good rinse. Preferably leave it to soak for as long as possible. Operate each of the control buttons dials switches while in the freshwater. This will help dissolve any salt crystals inside the control button shafts and other areas. Remember to not leave your housing in a public rinse bucket, as other cameras may knock it around and break the seal.

Push each and every control and turn every dial while your housing is submerged in a fresh water rinse tank

• If you are not going to dive with the housing for a week or more then an additional step of simple maintenance is to lubricate each control button and dial shaft with one drop of SiliconPump (available from your dive store or visit www.mcnett.com). Please confirm with your housing manufacturer or retailer that this is safe for your particular brand of housing. Each control on most acrylic (clear) compact & DSLR camera housings has a small slot that allows water to drain from the shaft and ‘O’ Ring. By blowing (with your breath) into this slot (or close to it), any water left after rinsing will be expelled. With many alloy DSLR housings there is no slot for water drainage, but by blowing (with your breath) close to one side of the control, excess water will still be expelled. Then using a small eye dropper one drop of the Silicon Pump liquid can be dropped down into this slot, or run-down the shaft, lubricating the ‘O’ Ring and control shaft.

Silicon Pump

An Eye Dropper

Pour the Silicon Pump into a small dish or container

Fill the Eye Dropper with Silicon Pump liquid

This Silicon Pump is harmless to the black (butyl) ‘O’ Rings used on nearly all camera housings. This includes all acrylic (clear plastic) and alloy compact housings & DSLR housings. Common housings like Canon, Olympus, Fuji, Nikon, Ikelite, Fantasea, 10Bar, Aquatica, Subal, Sea & Sea, Seatool, Nexus & Patima all use black rubber ‘O’ Rings for their rotating and push button controls.

Using the Silicon Pump filled Eye Dropper, squeeze a drop of the liquid onto each control on the housing. Allow it run down the shaft of the control/button, so it reaches the ‘O’ Ring. Push each button and turn the dial of each control after lubricating. Then let it sit for a few minutes. Note: Some controls are difficult to access, you may need to place the housing upside-down to allow the Silicon Pump liquid to run into the ‘O’ Ring area.

• DO NOT get any of this silicon lube onto the front lens port or inside the housing. Wipe off any excess drips from the housing and operate the buttons and control dials a few times after lubricating. Once all of the shafts and buttons have been lubricated and operated a few times; leave the lubricant to sit for a few minutes, and afterwards shake the housing gently to remove the excess lubricant (Best do this over an old newspaper, rather than the lounge room carpet!).

Next remove the main body ‘O’ Ring from the housing. You can use an ‘O’ ring picker (some manufacturers supply their housings with these), a tissue or even an old credit card (with a rounded corner), to remove the ‘O’ Ring.

• The only ‘O’ Rings that do not benefit from this lubrication are the main body and port ‘O’ Rings, which are sometimes made from silicon rubber which is softer and more pliable. Use only the ‘O’ Ring grease supplied by your housing manufacturer to lubricate these ‘O’ Rings. In almost 99% of housings today, any silicon rubber ‘O’ Rings are generally colored blue, red or yellow. These are the ‘O’ Rings that are lubricated with the manufacturers own silicon, usually supplied in a small tube.

Silicon ‘O’ Rings are normally coloured Red, Yellow or Blue. These ‘O’ Rings are made from silcon rubber and should only be lubricated with the silicon lubricant supplied by your housing manufacturer.

• If the main body ‘O’ Ring is left continuously in-place in the housing with the rear door closed it is constantly under pressure and eventually loses its shape. It is no longer round, but slightly flattened. This reduces the ‘O’ Rings ability to seal against the housing. Once removed, the ‘O’ Ring should be cleaned (see Pre-Dive Maintenance above) and put in a plastic zip-lock bag and placed inside of the camera housing, this way you can’t forget to install it next time you dive, as the camera won’t fit the housing with the bag inside!

Place the main body ‘O’ Ring in a small zip-lock plastic bag, this will protect while being stored.

Place the plastic bag with the ‘O’ Ring enclosed inside of the housing. This way you won’t forget to install it before putting in the camera again.

Clean the ‘O’ Ring groove with a tissue to remove any water and sand/ dust particles and close the back of the housing (with the ‘O’ Ring inside, in a bag).

close the housing ready for storage

Long Term Maintenance

Long Term Maintenance should be carried-out every year. Contact your housing and strobe manufacturers or your underwater photography retailer and ask when they recommend that the control ‘O’ Rings should be replaced or any other maintenance they recommend for your housing or strobe.

Following these simple steps will go a long way to helping your camera and housing last for many years.

Jeff Mullins teaches underwater photography from his home in Tulamben, Bali seeReefWreckandCritter.com for details. He also manufactures a fit-yourself Leak Detector for many types of camera housings see UWleakdetector.com for information.

from.divephotoguide.com

Camera Settings for Macro & Wide Angle

This is largely meant for compact camera users, if shooting with a DSLR, please refer to the separate macro and wide angle articles found in the Technique Section. The settings you will use will largely depend on whether you are shooting macro or wide angle. A good tip is to go into a dive with your settings appropriately adjusted for underwater use. A good benchmark that many beginners use is to go into the dive shooting at 1/125 and f/8. You will most likely have to adjust the settings depending on whether you are shooting macro or wide angle, but this is a good starting spot. Using your camera’s lowest ISO is also a good starting point to minimize noise in the image.

Macro

For macro, depth of field is important due to the nature of the photograph. Be aware that if you are completely zoomed in on macro mode, less of the image will be in focus than when shooting all the way zoomed out. Since you will often be zoomed in, high (smaller) apertures are usually used for macro photography.

Your shutter speed will largely depend on the conditions of the dive, how fast your subject is moving, and whether you are using a strobe (or strobes). If there is a current or the water is choppy, it may be hard to get yourself steady, and faster shutter speeds are required. Additionally, if you are shooting a moving fish, you may need a faster shutter speed than if shooting, say, a lethargic frogfish. The settings will change significantly if you are using a strobe. For the most part, when shooting macro with flash, you are basically shooting all artificial light and no ambient light. This means you can use higher f-stops and faster shutters speeds. Additionally, the flash will freeze the action, so the shutter speed can mainly be used to moderate exposure.

Wide-Angle

For wide angle, use the camera’s light meter to determine a good ambient light setting. The light meter is usually located on the bottom of the viewfinder or LCD screen, depending on which you use to compose your image. It consists of a number of “ticks” or marks in a horizontal line ending with a + on one end and – on the other. These ends represent over and under exposure ranges. In the middle of the line is larger tick with a 0 underneath, this represents a correct exposure. If you half click the shutter, your camera will read the light and place a line where it believes your exposure will be if you take the picture with your current settings. Since the light varies throughout most wide angle scenes, take meter readings against an area that represents the mid-range of exposure in your scene. However, remember that the light meter was designed for land use, not underwater, so review your image and adjust your settings accordingly. The light meter is only meant to be used as as starting place. It's important to remember that strobes are only able to illuminate a foreground subjects several feet in front of the camera. You are always relying on ambient light for the mid-ground and background. You can learn more about lighting in our Lighting Guide.

Additional Adjustments

If you don’t want to shoot in full manual mode, there are still some adjustments that you can make which will give you some control and help you create stronger images than you can on full auto pilot.

Exposure Compensation

If you are shooting in automatic (P), aperture priority (A or Tv) or Shutter priority (S) modes you have opted to give up most of the control over exposure to the camera. Even in aperture or shutter priority modes, if you attempt the change one setting, the camera will change the other settings to compensate. However, there is a way to adjust exposure in these modes — exposure compensation. Refer to your camera’s manual on how to change your exposure compensation, also known as your EV. You can adjust your EV by pressing the +/- button. Turning the EV up to +1 or down to -1 is the equivalent of one f-stop. You can usually adjust you EV in 1/3 stop increments. So, setting your EV compensation to +1/3 will make the image one third of a stop lighter than what the camera would have otherwise selected automatically.

If a subject contains a lot of white, it can easily be overexposed. If you like how your image looks, but your settings overexpose the white, try turning your EV compensation down a little.

Bracketing

Exposure bracketing is a technique used by photographers to help ensure they capture a correctly exposed imaged. It is a simple technique that is especially important underwater, where lighting is inherently complex.

When you take an image, you adjust the settings on your camera and your strobes so that the right amount of light reaches the camera sensor and produces the correct exposure. When shooting wide-angle, you usually meter on the mid-range of blue water so that the water is properly exposed as a nice (subjective) shade of blue. However, light can be tricky underwater and what your camera’s light meter thinks is the correct exposure doesn’t always result in the image you envisioned or what you see in your viewfinder. If you bracket this exposure with another one that is slightly underexposed and another that is slightly overexposed, you can help compensate for the possibility of an incorrect exposure. Depending on your exposure mode, you can either step your aperture or shutter speed a stop down or up, or adjust your EV compensation.

Additionally you can bracket by adjusting strobe position and/or power settings. Particularly when shooting macro, most, if not all, of your image is lit by your strobes. In this case, you may want to bracket the exposure by adjusting your strobe power rather than with your camera settings. Bracketing is especially useful in tricky lighting situations and scenes with a high dynamic range, like if you are shooting into the sun, a situation that can easily deceive your camera’s light meter into underexposing most of the image in order to not over expose the areas of the image close to the sun. If you are just getting started in underwater photography, bracketing can help you get the right shot. Reading the LCD screen underwater can be difficult and takes some getting used to, so its not always safe to assume what looks properly exposed on the camera screen underwater, will look properly exposed on your computer screen topside. Always consider bracketing images to get the best results.

Experiment

There is no such as thing as the "right" settings. As the light changes, your settings will need to change. Play around with your settings and see what works best. Sometimes it's trying something a little different or unusual that gives the most striking results.

from.divephotoguide.com

Taking Control Of Your Images With Manual Settings

There is nothing wrong with shooting in auto mode. Underwater photography is inherently fun and exciting enough that dealing with manual settings is not for everyone. However, taking the next step into manual mode opens up endless possibilities with underwater photography. The main advantage of using manual settings is that you take full control of your image. The camera is your tool, not your brain. If you have a specific image in mind, the only way to turn it into a photograph is by using manual settings, because the camera can’t read your mind. Additionally, shooting in manual mode makes the actual shooting process more fun. Trying to find the right settings, so that the image taken matches the one in your head is like trying to solve a puzzle. Few things are as rewarding as nailing an image you have spent time thinking about and then perfecting. Even if you decide to shoot in auto mode, understanding how the camera works and what the settings mean will improve your photography.

Shooting in manual allows you to take complete control over your images

The Jargon

When beginner underwater photographers hear terms like aperture, shutter speed or ISO they tend to freeze up and want to go back to auto mode. While the technical jargon sounds overwhelming, if you take a little time to think logically about the concepts, they’re really quite intuitive.

Even though the technology used in cameras has changed dramatically since their conception, the basic principles behind how they work remain the same. A camera has always been, and still is, little more than a lightproof box that contains some sort of light sensitive media. Today this is your camera’s digital sensor. At one point, not too long ago, it was film. A lightproof tube (a lens) is attached to the box. This tube contains a hole that can open and close (the aperture) to allow light to reach the sensor. You, when in manual mode, but your camera when in auto mode, can control how big that hole is (again, aperture) and how long the hole stays open (shutter speed) in order to determine how much light reaches the sensor. The end result of light hitting the sensor is a recorded image called an exposure. See, very straightforward!

This is of course an over simplification, as digital cameras have advanced mechanics and modern lenses contain complex optics—which usually require a strong grasp of physics and engineering to understand. But have no fear, you will never need to understand all of the complex theories and science that help your equipment work (unless you really want to). A third aspect, the ISO, which is the degree of light sensitivity of the sensor, can also effect the exposure and will be discussed later.

Aperture

The aperture refers to the hole in the lens, known as the diaphragm, that lets the light in.

The aperture regulates how much light reaches the sensor. The sizes are calibrated in terms of f-stops or f-numbers. The range of these numbers is as follows: f/1.4, f/2, f/2.8, f/4, f/5.6, f/8, f/11, f/16, f/22, and sometimes onward. Each number does not necessarily correspond to a specific size of the aperture opening, but is a relative number. Each aperture size (referred to as a stop) is marked with a corresponding number that represents half the light of the previous stop. For example f/8 lets in twice the amount of light as f/11 but half as much as f/5.6. Don’t get too worked up about the mathematical relationship of the numbers for now – just know that each stop either doubles or halves the amount of light.

Something that confuses beginner photographers is this: The smaller the f-stop, the larger the aperture opening. F/8 represents a larger hole than f/16 (as indicated in the image above) and lets in four times as much light (2 stops). Smaller f-stops have larger apertures, which means a larger hole size. It’s an inverse relationship.

The f-stop values mentioned above are fairly standard among lenses; however, you may see some differences at the ends of the spectrum. Some lenses don’t have the extremes. In fact, most point and shoot cameras’ highest aperture is f/8. To learn how to set your camera’s aperture, refer to your manual.

So, what does changing the aperture mean in terms of the image? Since the amount of light reaching the camera is dependent on the aperture, the overall exposure is altered by changes in aperture. For example, if you were taking a picture of a starfish at f/ 5.6 and f/8 and all other things remained constant, the photograph taken at f/5.6 would be brighter, or more exposed, than the one at f/8 and the image taken at f/8 would be darker, or less exposed.

This is a wide angle image at f/8.

This is the same shot but at f/5.6, note how it is lighter because the aperture is larger

This is the same shot again, but at f/11. The exposure is darker because the aperture is smaller

Depth of Field

The size of the aperture not only affects how much light reaches the sensor, but also how much of the image is in focus.

When you take an image you must pick a point of focus. Anyone who has ever used a camera has done this. You pick this point by placing the focus box on the subject. When taking vacation pictures of your friend, you usually place this point on your friends head. An area behind and in front this focal point will also be in focus. This area is called the depth of field. The depth of field is dependent on the aperture. The larger the aperture (remember, that means the lower the f-stop) the smaller the depth of field. This means that the area that looks sharp will be greater when shooting at f/8 than at f/2.8.

The fact that a smaller opening in the lens leads to a greater depth of field is counter-intuitive, but with practice, it becomes second nature.

Aperture Priority Mode

If you have a specific depth of field you want to acquire in your image, you can set your camera to aperture priority mode, usually indicated by an A or Tv on the mode dial. In aperture priority mode, you can select the aperture you want manually, and the camera chooses the shutter speed to get the best exposure.

Shutter Speed

There are two panels inside your camera that are like lightproof curtains on a window and block the light coming through the lens from hitting the sensor. When you take a photograph, you are opening these curtains and letting light momentarily hit the sensor. These curtains are called the shutter, and you can manually set the time you want them to stay open for. This length of time is called the shutter speed.

Shutter speeds are expressed in fractions of seconds (and sometimes full seconds). Just like a lens has a range of apertures, your camera has a range of shutter speeds. Common ranges on cameras are 1/1000 s, 1/500 s, 1/250 s, 1/125 s, 1/60 s, 1/30 s, 1/15 s, 1/8 s, 1/4 s, 1/2 s, 1s, 2s, and so on. For example, a shutter speed of 1/125 means that the shutter will be open for 125th of a second. Just like with f-stops, there is a mathematical relationship between different shutter speeds—each shutter speed stays open half as long as the one above it, or twice as long the one below it. For example, 1/30s allows light to reach the sensor for half as long as 1/60s but twice as long as 1/15s. Since the shutter speed determines the length of time that light hits the sensor, it will affect the overall exposure of the image by halving or doubling the exposure. An image shot at 1/30th of a second will be lighter than one shot at 1/60th of a second because light had twice as much time to go through the aperture.

Freezing Motion

Shutter speed also effects motion in your image. A slow shutter speed will blur motion, while a fast one will freeze it. If you think about it, this makes sense. Say you are shooting a fish and have the camera at a shutter speed of 1 second. When you take the shot, the shutter is open for a full second, enough time for the fish to swim right through the frame. The fish’s entire path through the frame will be recorded, and because it was constantly moving, it will be a blur. Now, imagine you are in the same scenario, but you have your camera set to a shutter speed of 1/125th of a second. The shutter is only open long enough to capture the fish in a particular point in time, freezing the motion. Advanced underwater photographers will sometimes use a slow shutter speed to show the motion of a subject. However, for the most part, underwater photographers shoot with fast shutter speed like 1/60s or faster for stationary subjects. If not using a strobe, which also freezes the subject, shooting at even faster shutter speeds may be necessary because of something called camera shake. Unless you are perfectly still, which no one is, your camera is moving because you are moving. You will have to adjust your shutter speed depending on how steady your hand is.

The shutter speed selected for this image was too slow to freeze the antenna of the lobster

Shutter Priority Mode

If you know you need to shoot at a certain shutter speed to freeze movement, you can set your camera to shutter priority mode (usually indicated by S on your mode dial.) When in shutter priority mode, you choose your shutter speed and the camera chooses the aperture that it thinks will create the best exposure.

Getting the Right Exposure

To take full control of your image, you must use both aperture and shutter speed in conjunction with one another. Remember, going up an f-stop cuts the amount of light by half. Going up a stop in shutter speed also cuts the amount of light by half. This is a crucial, but extremely simple, mathematical relationship. Because of this relationship, if you increase your aperture one stop (e.g. from f/5.6 to f/8) while also slowing down your shutter speed a stop (e.g. from 1/125s to 1/60s) you will have the exact same exposure that you started out with. All of the aperture & shutter speed combinations below will achieve the identical exposure, but the depth of field and motion attributes will vary. An image shot at f/5.6 and 1/125s is exposed exactly the same as one shot at f/8 and 1/60s (assuming you have not moved and the light is exactly the same). This is because you halved the amount of light being let through the aperture opening, but let in twice as much light by keeping the shutter open longer. Once you find the right exposure, you can adjust the settings to get the right amount of depth of field and motion in the image. Suppose you take a picture of a goby and find that it is correctly exposed when shot at f/2.8 and 1/250s. However, at f/2.8, not enough of the goby is in focus as you desire. You can increase the f-stop to f/4 and slow the shutter speed down to 1/125s to increase the depth of field and keep the same exposure. Now, suppose the perfect amount of depth of field would be achieved with an aperture of f/5.6. You would need to slow the shutter speed down to 1/60s to keep the same exposure. However, slowing the shutter speed down that much introduced too much blurred motion in the image. If you keep the shutter speed at 1/125s, the image will be too dark, referred to as underexposed. You see, it's a puzzle! There is one last setting you can manually control to adjust the overall exposure.

ISO

The ISO represents how sensitive the digital sensor is to light. In recent digital cameras, ISO can range from ISO 100 to ISO 3200 or even higher in high end DSLR cameras. The higher the ISO the more sensitive the sensor is to light.

Therefore, shooting at ISO 100 requires twice the light as ISO 200. Perhaps you are thinking, “Why not just crank the ISO up as high as it can go so you can achieve maximum motion freeze and depth of field?” This seems logical. However, there is a problem with using higher ISO. The best image quality is achieved at the lowest ISO settings. At higher ISO’s we introduce a noticeable amount of “noise”. Noise is the term for areas of an image that have color and quality aberrations. This can be noticed mainly in the black or darkest areas of an image as multicolored speckles (pixels, actually). It gives the image an unsightly grainy appearance, especially in smooth monochromatic areas. That nice black background at ISO 100 will become a multicolored speckled mess at ISO 800. The problem is more prevalent in compact cameras than SLRs, but in both cases, noise reducing technology in digital cameras is getting better. The top of the line DSLRs can shoot at ISO 3200 and higher with noise being barely noticeable. That said, it is rare that you would ever need to go above ISO 800 underwater. It will probably only be necessary when shooting ambient light, wide angle shots on dark, overcast days. In Alex Mustard’s review of the D3 on DivePhotoGuide, he couldn’t find a situation that called for ISO 1600 and higher, even when actively searching for one. As a default, set your camera to its lowest ISO setting to have the least amount of noise. Increase it when you need a little extra light, like in the earlier example of the goby. Since every camera is different, experiment, and avoid noisy images.

The Best Exposure is the Correct Exposure

One of the main advantages of digital photography is being able to get instant feedback of an image via your camera’s LCD screen. The LCD screen will immediately display your image for review. This is a great way to learn the effects of different settings. Take a shot and review it, then adjust your settings and review the differences between them. What was the effect of changing your aperture or shutter speed? In the film days, you had to wait until you got back onto land and had the film developed to see if you got your settings right. Now, you just have to look down at the screen.

The Histogram

A lot of times, the underwater environment makes it difficult to accurately read an image’s exposure on the LCD screen. In these situations, it’s helpful to check the image’s histogram. An image’s histogram is a graphical display of its exposure. The tonal range of the image is graphed according to its brightness value. Tones to the left are dark and to the right are light. There is no right or wrong histogram because different shots require different levels of brightness. For a nice evenly exposed image, the bars on your histogram should be an evenly distributed wide bell curve.

If you notice that histogram skews to the left, the image is probably too dark, or underexposed. Slowing your shutter speed and/or opening your aperture may be the solution. Conversely, if the histogram skews towards the right, then the image is potentially overexposed. Increasing your shutter speed or closing your aperture will help limit your exposure.

One key thing to look at while reading the histogram is whether or not it “spills” off the edges of the graph. This usually looks like a lot of tall bars “bunched” up at either end of the horizontal axis. If these bars hit the vertical limit of the graph, then they are either too dark or too light for the camera to read. You may have heard photographers saying that a portion of their image is “clipped” or “burnt out.” This means that some parts of the image are too bright for the camera to read and those pixels’ tonal information is lost, resulting in a loss of detail. Additionally, an image with a histogram that has pixels maxing out the left end will have a loss of detail in the dark areas.

A histogram for a evenly exposed image, where there is no information lost to under or over exposure.

A histogram for a over exposed image-notice the histogram "spills" off the right end indicating areas of the image are "burned out."

A histogram for a under exposed image. Here is pixels are"spilling"off the left end.

Sometimes images that go beyond the bounds of the histogram are okay. For instance, a macro shot with a black background will have a histogram that has a lot of pixels at the extreme left end of the graph. This happens because the black is actually underexposed water, but in this case, it’s aesthetically desirable. In wide-angle photography, sometimes the sun will create areas that are burnt out, but still desirable.

This is the histogram for the image above. Notice that it spills off the left end, indicating that areas are under exposed (where the red arrow is pointing). This is actually the area that is the black background, which in this image is actually desired.

In most cameras with manual controls, you can set-up your camera so that the histogram is automatically imposed over, or placed next the image when it is being reviewed. Many photographers choose this setting because the histogram is more reliable than your eye when it comes to determining exposure. Additionally, in many cameras, there is a feature that can be used to quickly tell you if there are areas of lost pixel detail due to over or underexposure. Usually, the blown out area will flash on the LCD screen to indicate the issue. This is a valuable setting

from.divephotoguide.com

Shooting In Auto Mode

If you don't want to learn about manual exposure just yet, put your camera on auto mode – usually indicated by an Auto or a “P”(for program) on your camera’s mode dial. Note: "A" may be another option the mode dial but it does not stand for auto! Auto mode is the easiest way to shoot because the camera chooses the settings and manages the exposure for you. All you need to do is point and shoot.

The Auto Mode Blues

The problem with letting the camera choose the exposure for you is that cameras are not designed to be used underwater. As you’ve now learned, light acts differently underwater than it does on land (again, technically, in air), absorbing the warmer colors like red, orange and yellow pretty quickly as you descend, resulting in very blue images. To some degree, your eyes can adjust to this, so you see shades of reds and yellows, but your camera does not, so it can’t record those same colors. There are some easy solutions that can help restore color to your images, but if you choose not to use them, be warned: with the exception of very shallow water on very sunny days, your images will be singing the blues - literally.

Images can look very blue when shot in auto mode and without a strobe

“Can I Use The Built In Flash?”

Artificial light is the best way to capture the vivid colors underwater. However, using the on-camera flash in not advisable underwater, as its position close to the lens will create backscatter. The built-in flash is also fairly weak when used underwater. So ideally, you will need to buy an external strobe.

Buying a strobe is the one investment that will immediately and noticeably improve your photography, even more so than upgrading to a more advanced camera. For more on strobes, see our Lighting Guide. If you are just starting out, you may not want to spend the extra money on or deal with the extra hassle of an external strobe. Even the simplest digital cameras come with a built in on-camera flash, and all point & shoot housings are designed to enable the use of this flash. It can be helpful in restoring color and lighting small subjects when shooting macro photography, but ultimately the benefits of the camera’s internal flash are limited underwater. Our recommendation, of course – is to bite the bullet and buy at least one strobe if you are serious about learning more about underwater photography.

Shooting Without Flash

In the right conditions, you will be able to create great images without using any flash at all, only relying on the natural ambient light. Remember to:

Stay shallow

Shoot at mid-day (between 10am – 2pm) when the sun is high in the sky and the maximum amount of light is penetrating underwater

Shoot with the sun to your back, as you would on land (as you will soon learn this is not always the case underwater).

Here are a few more tips to help you create great ambient light images.

Using Filters

Filters are another option when looking to shoot without strobes. Filters are small colored gels placed in front of the camera’s lens that help adjust for color loss. There are filters designed specifically for underwater use that can be an easy solution for getting good color in your images.

Try Using Underwater Mode

Many recent compact cameras are equipped with an “Underwater Mode.” This mode attempts to adjust the camera’s white balance to compensate for the loss of color underwater without the need for an artificial light source.

Underwater mode works differently in different camera models, and generally it appears to be improving. Reports of the effectiveness of underwater modes range from pretty good to excellent depending on the camera model. For the most part, it works best in shallow depths of up to about 8 meters where plenty of sunlight still exists in the water column. In some cameras, the underwater mode even adjusts at various depths based on the ambient conditions. For example, there will be a different adjustment when shooting at 8 meters versus 3 meters because of the different amount ambient light at each depth.

Manual White Balance

If your camera has a manual white balance function, and you are inclined to learn how to use it, we recommend shooting ambient light images with custom white balance settings when possible (if custom settings are not for you, go ahead and skip to the next section).

Setting the custom white balance is actually quite easy. What it will do is maximize the amount of color captured at any particular depth / lighting conditions by calibrating against the color white and adjust accordingly for the light at that depth. Basically, you are telling the camera what white is (technically it reads white and adjusts for a specific tone of gray, but that’s a more advanced topic). In order to set the custom white balance, you will have to carry a white slate with you underwater. In a pinch you can use a patch of white sand or even the palm of your hand.

Here’s what to do.

Select custom white balance in your menu, fill the frame with the white slate and press the shutter. You should get an “ok”, “success” or “WB set” message. You have now set the white balance for that particular depth and lighting conditions. You’ll need to reset the white balance with every few meters of depth or each time the lighting conditions change. Keep in mind that you still will not be able to restore color at any significant depth without strobes.

Pick A Starting Point – Macro is A Good Choice

While you may have the desire to start shooting everything you see on the reef, in order to learn, you’ll need to pick a starting point. Ultimately shooting macro is easier than wide angle, so it’s a good place to start focusing your energy.

The first step is to put the camera in macro mode (if shooting with a point & shoot camera – SLR’s need to use a macro lens). Look for the flower icon to indicate macro mode. This mode allows you to focus closer to the subject than in normal mode. You may find that it takes longer to focus, so it is best used with relatively still subjects. However, the ability to focus closer will allow you to minimize the amount of water in between the subject and your camera and allow you to shoot smaller subjects, which would otherwise be mere specks in the frame if shot from farther away. Macro mode is the one area where trying your camera’s internal flash may work out in some cases. With small subjects, it is possible to light up the entire frame so the colors are reintroduced into the image. However, if the water isn’t very clear, you will notice backscatter in your images. Refer to your camera’s manual to see how to turn the flash on and off. To fill the frame as much as possible with your subject, try using the cameras optical zoom. The further in you zoom, the more the subject will fill the frame, making the subject appear larger. The more you zoom in, however, the harder it will be to focus. Make sure you half click and remain still when focusing and in telephoto. Don’t use the zoom as an alternative to moving in closer. This is a common mistake. Remember – closer is better! Using digital zoom is not advisable because you will lose image quality.

Slow moving macro subjects are a great place to start your foray into underwater photography

from.divephotoguide.com

Basic Principles of Light Underwater

Underwater photography presents unique challenges due to the properties of water and its effect on light. Water absorbs light in ways that air does not. Therefore, it is important to understand the ramifications of this fact and what you can do to compensate and capture good images underwater.

Unlike shooting on land, available light (the sun) alone will normally not provide the right light to produce the colorful and pleasing images that you were hoping for. Underwater, light is affected by:

Depth

Subject distance

Weather and surface conditions

Light Loss

Water is approximately 800 times denser than air, and this density absorbs light - quickly. Not only does this result in dull, monotone colors, but it also decreases contrast and image sharpness. New underwater photographers often get frustrated from the blue / gray hue of their images - a direct result of the properties of water and the affect of light absorption. This is actually a very common problem and there are several approaches to reintroducing color and clarity to your images.

Specific frequencies of ambient light get absorbed at different depths, from the longest wavelength to shortest (basically the colors of the rainbow, remember ROYGBIV?). Red nearly disappears at around 5 meters, followed by orange at 10 meters, yellow at 20 meters, green at 30 meters and eventually even blue at 60 meters.

Due to this color loss underwater, underwater photography requires a means of compensation to restore the colors and contrast lost from absorption. The ideal way to accomplish this is by using artificial light (underwater strobes), but that is not to say that you will not be able to enjoy underwater photography without strobes, it is just the optimal solution.

from.divephotoguide.com

Top 10 Basic Principles Of Underwater Photography

Learning the technical jargon is not for everyone. In fact, don't even worry about it right now. However, shooting marine life underwater is not as easy as shooting on land (technically in air), and even a simple point and shoot camera underwater requires a little extra thinking.

The first step to understanding any kind of photography is understanding your camera. If you are brand new to digital photography, take the time to read the camera’s manual.

The Fundamentals

No matter what camera you have, from an entry-level digital "point & shoot" to the most expensive dSLR , there are ten golden rules of underwater photography that you must always remember. Many of these rules are related to composition in the underwater environment. Every photographer can benefit from proper composition, so it is also worthwhile to read the entire Composition Guide. 1) Get Close, And Then Get Closer! The overarching mantra of underwater photography is to get close. Or, better phrased - "get as close as you think you need to get, and then get closer!"

Water absorbs light very quickly, and the most common complaint for new underwater photographers is the dull blueish-greyish hue of their images. Removing the amount of water between the camera and the subject will mean a clearer, sharper, and more colorful image. Additionally, in water, there are tiny floating particles that you might not notice until they show up in your images. We refer to these particles asbackscatter. Minimizing the amount of water between your camera and your subject will also minimize the amount of backscatter in your images.

2) Shoot Up

In underwater photography, images usually turn out better when shooting at a slight upward angle towards the subject. Shooting down on the subject is often easier, as the reef is usually below us while we dive, but images of the tops of fish and coral are not interesting. Shooting up creates a more appealing view of your subject, and can create much needed contrast between the foreground subject and the background of your images. By shooting up, you can often also include the open water in the image, which is a better background for an image than a cluttered area of the reef.

The image shot on a downward angle is not that effective

This image, shot at eye level, is much more interesting.

3) Focus On The Eyes

Getting images in focus is, obviously, necessary for a successful image. Everything else can be perfect, but if the subject is out of focus, then, well, it’s really just an image of an ambiguous blurry thing.

In wildlife photography, one of the most important rules is keeping the eye of the subject sharp. Place the focus bracket (the little crosshair looking thing you see when looking at the LCD screen or the viewfinder) so it aligns with the subject's eye, depress your shutter button halfway to focus in on the eye and then when you have your photograph composed, push down completely on the shutter. Voila – you’re now in your focusing groove!

Notice how much impactful the side of the image where the hawkfish is making eye contact is than the side where the eye is turned around and "missing"

4) Keeping Yourself Focused

Diving with a camera and diving without a camera are two totally different activities. After diving with a camera, you may find that those dives where you just cruised along casually observing the scenery no longer seem quite as fun. Carefully perusing the environment for the next photo opportunity is the name of the game now, and there’s no going back. Patience is paramount in underwater photography. Waiting for your subject to assume the perfect position or letting other divers go by so that they are not in the frame are things you will have to get used to. It’s not uncommon for advanced underwater photographers to spend multiple dives on a single subject – even a common subject. The results can be worth it. Of course, the casual underwater photographer doesn't need to be obsessive, but a level of personal focus and attention to detail will take your photography a long way!

5) Use a Strobe

Since water absorbs light and sucks the color out of underwater images, use underwater strobes to restore color, create contrast and help retain image sharpness. This may be your single most important investment.

Because of the way light penetrates water, many images look very blue without using strobes. Additionally, strobes freeze movement which helps avoid blurry images.

Using a strobe can make all the difference

6) Shoot, Review, Adjust, Rinse, Repeat

Sometimes we take for granted the shortened learning curve that digital photography has created by giving us immediate access to review our images. To an extent, the LCD screen on your camera may be its most important feature. Take advantage of this feature and take the time to review your images as you shoot to make sure your subject is well exposed, nicely composed and you are happy with outcome. Review every image if possible. Don't like exactly what you see? Adjust accordingly and shoot again (you'll learn how to adjust soon, we promise.) New photographers may find it hard to understand how anybody ever acheived good results with underwater photography prior to the advent of the LCD screen. In fact, capturing good underwater images on film was indeed much more difficult than it is today.

7) Go Manual

Starting off in auto mode is not a problem. But auto settings can only get you so far in underwater photography. To really control the exposure, color and sharpness of your images and to get creative you’ll need to embrace some degree of manual controls. Don’t worry, it’s not that scary!

8) Maintain Your Equipment

Water and electronics don’t mix very well. It’s important to take your time when setting up your camera and housing. Make sure o-rings are clean and greased, but not over greased. One strand of hair or spec of dirt can be the difference between keeping the ocean out of your housing or flooding it. Assuming you are shooting in saltwater, rinse your camera gear off with fresh water after every dive. Never let salt water dry on your equipment. For more information on maintaining your underwater gear, read our guide to maintenance.

Maintaining your equipment is part of being a successful underwater photographer (Photo by Jeff Mullins)

9) Respect the Environment

Remember, we are priveledged guests in the underwater world. Respecting the environment and its inhabitants should be one of your top priorities. Before you start taking your camera underwater it is important to have excellent bouyancy skills, this will help protect both yourself and the environment around you. Keep all of your gear streamlined as to minimize the potential of a gauge or hose getting entangled or damaging the reef. Never harrass or touch marine life. You may not realize the damage inflicted from even minor touching. Be patient and let your images be the reward from your interactions.

10) Have Fun!

Don’t forget that underwater photography is supposed to be fun. Don’t get too caught up in the technical side. Start off with the basics, get a feel for it, and learn the technical side later. Go get wet and enjoy yourself!

from.divephotoguide.com

Selecting Your First Underwater Camera

Selecting an underwater camera is not a simple task. There is no one best or right underwater camera to buy, but rather the best or right camera for your specific needs and budget. Fortunately, with the growth of underwater photography, manufactures have been forced to cater to a wide range of desires and demands, resulting in an underwater camera option for every level of photographer.

To be clear, other than several discontinued film models, there are no actual underwater cameras. To shoot underwater photography you will need a digital camera and a waterproof housing designed specifically for that camera. Sometimes the camera and housing are sold together, but more often they are not, or the housing manufacturer is a third party to the camera brand. That being said, recently manufacturers have begun to produce waterproof digital cameras, but the current depth rating is limited to 30 feet, and often even less.

For this underwater camera guide we will use the term “underwater camera” to describe any combination of camera and housing that can be used underwater. The best way to use the guide is to learn about the criteria required in your decision making process, browse or search our Underwater Photography Equipment Guide, and then contact an underwater photography retailer to discuss current models and options. The best advice is to select the camera based on available underwater housings and accessory options. If you already own and shoot with a camera on land and are comfortable and happy with it, whether point & shoot or DSLR, housings may be available for your camera. Check our Underwater Photography Equipment Guide to see what options exist. However, you may still choose to start with a different camera based on the criteria and recommendations in this guide.

This is an image from one of my first dives with a camera. I will always be partial to my first camera, an Olympus 5060 in an Olympus housing

Compact Camera or DSLR?

If you are beginner with photography in general and need to purchase a new a camera, chances are, you will start with a point and shoot camera (also referred to as a compact camera) because of their ease of use, price and versatility. There are different levels of point and shoot cameras, ranging from the bare basics to fully featured options.

While there is no question that the image quality produced by DSLR’s is on average better than that of a compact camera, it is NOT about the equipment, it is all about the photographer. Equipment alone will not help you produce better images. Never forget that.

DSLR’s offer higher quality interchangeable lenses, no shutter lag, and generally better sensors, but also come with significantly higher costs, weight, bulk and complexity.

There are three main factors that go into choosing a camera

Features

Budget

Size and weight

Finding the right combination of these three factors depends on your personal preferences and photographic intentions. The first step is determining what features are most important to you. It may be that you have strict size, or more often, budget requirements that will limit which features you can have in your camera. In any case, if you have not done so yet, we highly recommend reading The Basic Principles of Underwater Photography article first to get more familiar with what underwater photography entails and the challenges you will need to overcome.

Underwater Camera Features

The first, and perhaps hardest, step of buying an underwater camera is deciding what you want to achieve from your photography. The more you want from your images, the more options you will need from your camera. This step is tough because it requires looking ahead a year or so. Manufactures are constantly trying to cram the most features into the smallest camera at the best price, but usually there is a compromise. Prioritizing the features that matter most to you is the best first step in selecting a camera. This list is a good place to start your triage of camera capabilities, and is more geared towards compact cameras.

Housing Availability

Even if there are housings available for a particular camera model, you will want to investigate what features your housing has. Are all the camera controls accessible? What types of connections are available for external strobes? Are external add-on lenses available to allow you to shoot wider angle or closer macro? These are all important items to investigate. Some point and shoot models only have one housing available while the more advanced point and shoots and DSLR’s usually have multiple housing options. 

Three Different Housings For the Canon G10

Manual Controls

This is the single most important decision you will make when selecting an underwater camera. While you can shoot photography on land in automatic mode without an issue, ideally you will need more control over your images underwater. This is for two main reasons:

Reason 1: Simply put - automatic mode does not work as well underwater as it does on land. Relying on the camera to help achieve good exposure and color is just nowhere as effective underwater because your camera was not designed to deal with light in water. For more information on the basic principles of light underwater and why using manual controls is so important in underwater photography, please refer to the Basic Principles of Underwater Photography

Reason 2: Underwater photographers are different. Most underwater photographers (which we define as anyone who takes an image underwater) want more than just snap shots that prove they were diving - they want images they can be proud of. “I was on a dive trip with a woman who borrowed a basic point and shoot camera for the trip. She said she just wanted to show her mother what she saw, and did not want to be ‘distracted’ with a camera on her dives. She started in full automatic mode, but became increasingly dissatisfied. By day five we were going over manual controls. By day 11, she was capturing much better images and was hooked on photography, asking what camera of her own she should buy.” The point is, even if you think you want to shoot only in auto mode, there is something about being underwater that might quickly change this. That said, shooting auto is better than nothing. I am sure many underwater photographers have a lifetime of fun on auto mode. Just make sure you understand its limitations before purchasing a camera that does not offer manual controls. If you do go fully automatic, chances are that many other features won’t interest you, so prioritizing by size or price might be your best bet.

Manual White Balance

Manual white balance becomes important if you are planning on shooting without strobes and only using ambient light. Because of the properties of water, images using only natural light will appear blue. Manual white balance is an effective way of removing this color cast. If you plan on purchasing strobes, this is not as important. Again, refer to the Basic Principles of Underwater Photography to see if manual white balancing is something important to you.

I used the white balance feature on my Olympus 5060 to bring back some color in this image that used no flash

Lens Options

If you’re planning on shooting with a point and shoot camera, your selection of housing will in part be based on its ability to accept external “wet lenses”. These wet lenses are supplemental optics that are placed over or in front of the port to enable wider angle or closer macro shooting. If you’re interested in wide angle shooting, ideally we recommend selecting a housing / camera that can fit one of the third party fisheye wet lenses. These lenses allow you to get as close as possible to the subject, which will result in more colorful and more detailed images.

If you’re shooting with a DSLR, each brand has high quality lenses available, and the lens choice will not dictate the camera decision. You will, however, need to ensure that you use the appropriate ports for each lens.

Shutter Lag

Compact cameras have a distinct delay between the moment you depress the shutter button and when the actual image is captured. This shutter lag varies by model. Shutter lag can be frustrating when shooting moving objects like fish and other wildlife as the subject may have moved from the time you pressed the shutter to the when the image is captured. Try to select a model with the least possible shutter lag. The higher end compact cameras have significantly improved and have a very small amount of shutter lag.

RAW Files

Different cameras produce different types of image files. If you don’t plan on doing a lot of editing of your photos in Photoshop or another editing program then shooting images in JPEG is fine. If you do plan on editing your images then consider selecting a camera that produces RAW files, which are uncompressed files that preserve the most data possible, which is a valuable attribute when editing your images.

This image was shot with my first camera, an Olympus 5060 and a Sealife 960d strobe, on my first ever photo trip. Part of the reason I chose the Olympus 5060 is because it had the ability to shoot RAW.

Megapixels

Don’t fall for the megapixels hype. Doubling the megapixels does not double the resolution, it increases resolution only by approximately 40%. So going from 8 MP to 10 MP only increases resolution by 8%. Other aspects of a camera, mainly the sensor size, are a better indicator of quality of the images it produces (This is why a 10 megapixel DSLR produces superior image quality than a 10 megapixel point and shoot camera. The DSLR has a larger sensor and each individual pixel is larger, records more information, and therefore the image quality is better). 2009 marks a trend in brands actually lowering the megapixel count in some models. For example, Canon released the G11, its flagship point and shoot camera, with less megapixels than the G10, but with a better sensor and therefore improved image quality. Unless achieving very large, gallery quality prints is your primary objective, don’t worry too much about megapixels at this point.

Video

The video revolution is upon us. We are no longer limited to stills. Most point and shoot cameras have a video mode that lets you shoot short movies, and now DSLR’s also offer video capabilities. The decision now is what video quality you desire - standard or low quality HD on point and shoots, or HD on a DSLR. Remember that movies are large files and that a still camera is not the ideal option if your main objective is to shoot video. That being said, some of the new DSLR’s with HD video capabilities boast cinematic quality.

Size

For some people, size matters most. Already burdened with large bags of dive equipment and clothes, for some it’s just too much to add a large underwater camera rig. Luckily there are cameras that fit in any normal pocket, and the plastic housings are light and small enough to stick in an already stuffed carry-on. These cameras usually have limited features, but are continually evolving. If you decide to travel with accessories like strobes and add-on lenses then the size of the camera almost becomes negligible, and should not be a major factor.

Something To Keep an Eye On...

Recently, waterproof digital cameras have gained in popularity among consumers, leading to a sudden increase in options. Waterproof cameras, sometimes referred to as amphibious cameras, are designed so that they don’t require a housing to be used underwater. The major issue with these waterproof cameras is that they can only be brought down to relatively shallow depths. The best cameras are only waterproof to depths of 10m/33 feet. Despite eliminating the need for expensive and bulky housings, the current selection of waterproof cameras are not practical primary dive cameras on anything but the shallowest dives. They are, however, great cameras to bring a long to the beach, take on the dive boat or use snorkeling. It will be interesting to see what the future holds for waterproof cameras. Will we soon see waterproof cameras rating to recreational diving limits? We think so – over the next few years. And this will change the market drastically.  

Underwater Photography Equipment Costs

Obviously underwater photography can be equipment intensive. A large part of choosing your first camera may come down to budget.

Unfortunately, even if we want the best of the best, it does not always mean we can all afford it. Underwater photography is not a cheap hobby. Housings, strobes, ports, focus lights, strobe arms and other accessories and gadgets can be added on to make your already expensive camera even pricier. There are two main things to consider when it comes to budget:

Budget, and Then Add 50%

The first thing to consider is spending slightly more than you may have originally budgeted for, particularly if you think that

there is a chance you will want to upgrade in the not-too-distant future. If you buy a smaller, simpler camera first, only to decide in six months that you want the features of a more complex and expensive camera, then you will have ended up spending more money in the process. This is a common problem. It is not necessarily more difficult to use a camera with more features, so you can always grow into your camera.

Don’t Forget the Strobe(s)

We strongly recommend considering at least one strobe in your budget. The addition of a strobe (or strobes) will increase the quality of your images more so than upgrading to a “better camera.” Ideally get a mid-range strobe that you will be able to transfer over to your inevitable camera and housing upgrade down the road.   To reiterate, we can't stress the importance of strobes enough.

Accessorize

While accessories often seem like optional add-ons, in underwater photography many of the accessories will make shooting more convenient and/or productive. Wet lenses, camera trays, strobe arms, focus lights, and carrying cases are just but a few of the accessories that will help you in your underwater photography quest.

Plan For Murphy’s Law

Underwater photography and Murphy’s Law are long time bedfellows. Plan to buy extra batteries, some spare parts and minor tools. Sometimes having a little “McGyver mentality” goes a long way and can save you in a pinch. Cable ties, surgical tubing, duct tape and other do-it-yourself patch-up materials have so many miscellaneous uses and can be invaluable when Murphy’s Law strikes. Definitely bring extra memory cards, and another really good idea is to also bring a card reader and a laptop or hard drive. The last thing you want is to lose or damage a memory card with all of your images on it. Live by the mantra of backup, backup, backup and you can never go wrong. As you can see, when buying a camera for underwater photography, it is usually just the tip of the iceberg of equipment you’ll need. But that’s all part of the fun!

from.divephotoguide.com

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