Everything You Wanted to Know about Installing Surveillance Cameras that Get Results PART TWO
In Part One of this series, we discussed camera selection and resolution.
At this point it might make sense to start talking about the different type of sensors, how CCD sensors and are most prominent imaging sensors found in most security cameras and how they are different from CMOS sensors, but wait, this discussion might just start putting you to sleep and that is not my goal.
So we are going to move on to some more core factors relating to video quality which will greatly help you identify the right camera for the job. Perhaps at some later time we will talk about how CCD sensors are better for night vision than CMOS, and why CMOS is the most prominent sensor in Internet Protocol based cameras a topic we will get into shortly.
Considering our current predicament of living on a planet that rotates once every twenty four hours, we need to talk about night time imaging via security cameras since we spend a good portion of lives in the dark. The ability to see in low light (or no light) is an important factor to consider when looking at both indoor and outdoor cameras. Actually, now that I have brought up indoor vs. outdoor cameras I could venture into a discussion of the difference, but that will have to wait a bit because we need to first talk about night viewing.
Each camera’s sensor has a lot to do with its ability to see in low light. If the sensor is not sensitive enough, you just can’t see very well at night. As you probably know, the camera sensor is a lot like the rods and cones in the back of your eye which give you the ability to see at night. Not all camera sensors are equal, and many sensors are terrible at night vision.
The ability to see in low light (or no light) is an important factor to consider when looking at both indoor and outdoor cameras.
This brings to mind those retail outlet style cameras with their poor night vision quality and a story about a silly conversation I had once with a customer. It turns out that contrary to my polite and unselfish explanation as to why she ought to stay away from retail style cameras, she went out and bought a retail surveillance system for her store. One day when she had me over to do some networking work on her Internet router (this had to do with getting her DVR on the Internet) she sheepishly complained about the night vision quality of her inexpensive retail cameras and how little she could see with them at night. I turned to her and said in the nicest way possible,” you need to spend more money for good night vision.” She responded,” I would never spend over $200 on a camera!”
The facts are that I never brought up the amount she needed to spend, because it would certainly be a bit more for good night vision. I didn’t have the heart to tell her that an effective night vision camera can run around $300-$500 per camera. I didn’t have the heart to tell her she was cheap and short sighted and that her store was an easy target for some neighborhood criminal looking for a quick score. So I kept my information to myself, since her ears were obviously filled with some kind of thick and oozing wax. I came to this conclusion since she didn’t hear me originally when I told her retail store camera systems were a waste of money and would never give her quality or prosecutable imagery.
I’m going to now get slightly technical on you and talk about light sensitivity measurements, but don’t worry, just pay attention to the next few sentences and you’ll be able to know what kind of numbers will give you effective night vision even if you don’t follow me completely. I’m not trying to hurt you, but we need to address some numeric values and it will be helpful enough and necessary. Take a deep breath and steel yourself.
When we look at night vision sensitivity it is measured in numbers like .0002 or .1 or .001 lux. The more zeros before the number and after the decimal the better. So if you have to choose between a camera with a light rating of .2 lux or a camera with .0002 lux, which one is better? That’s right, the .0002 lux rating. Actually, it’s much better. Now that wasn’t too hard was it? Just remember, the more sensitive the camera, the more zeros will appear after the decimal.
Be sure to check back for Part Three of this continuing series.
