CMOS
Basically there are two types of camera. Cmos (complementary metal oxide semiconductor) cameras are the least expensive to manufacture because of the relative simplicity of their sensor pick-ups. The measurement of image quality largely depends on the resolution of the camera. Resolution is measured in horizontal tv lines. There are just over 600 lines of horizontal resolution on a PAL television. The higher the resolution of the camera (more horizontal lines) the more defined the final image will appear. Cmos cameras tend to be slightly smaller then CCD cameras.
Currently, cmos cameras go upto 380 tv lines. You 're talking about an image quality comparable to that of a cam-corder of a few years ago, the ones that used to take full sized vhs tapes? Now when you consider the size of these tiny cmos cameras next to the size of our latter day shoulder riding friends it's pretty amazing.
We quite often use a cmos camera in some obscure (high risk) position as a second camera using a simple video switcher to change to the camera we want the shot from.
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CCD
The other type of camera is a CCD camera (charge coupled device). CCD cameras have much more complicated circuitry to produce a sharper image and a more realistic reproduction of colours. The best CCD "bullet" style cameras available at the moment can display up to 480 lines PAL which is a nice sharp clear image, in reality, any camera of this size displaying upwards of 420 lines will give you good picture quality.
CCD "bullet" cameras allow more light to the sensor with bigger internal lenses which makes the final image camparable to a mid-range cam-corder.
For the DogCam we chose a Sony camera 480 tv lines, it has excellent pick-up with a 3.5mm lens for the best light spread. The DogCam is a class CCD colour camera in a hard water-proofed casing. A treated outer lens specified by ourselves lets only the preferred light spectrum in reducing glare and minimising over exposure.
Our latest camera, the DogCam Pro 550 zoom is the best camera to use if you are looking to make high quality DVD resolution videos. 550 lines is the optimum resolution for recording on to a camcorder. This camera has been designed by DogCamSport and includes some very clever image processing allowing it to change it's settings automatically to suit your filming environment. This camera is recommended for filming in the snow where over exposure would bring a lesser helmet cam to it's knees.
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Over Exposure
Is what you get when too much light gets to the camera sensor, like opening your eyes to a bright light first thing in the morning. Any camera will over expose if you point it at the ground and then quickly towards the sun. It's about how long the camera takes to adjust that determines a quality of the unit. Cmos cameras have the most difficulty in adjusting quickly to fast changing light conditions. CCD cameras handle this much better.
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