There are several choices for CCTV camera lenses.
London has 10,000 CCTV cameras scanning the city for security. You may not have that kind of blanket surveillance but if you have any closed-circuit cameras at all, you will want the best lenses for your situation. Elements to consider are lens focal length, CCD size, aperture, iris control and the mounting system.
Instructions
1. Decide how wide an angle of view your system requires. A lens focal length of 2.5mm will provide a wider field of vision and a longer focal length while 16mm will give a narrower view. The size of the image sensor or CCD (charge coupled device) chip in the lens will also affect the angle of view, with larger chips providing a wider angle of vision.
2. Select a lens with an aperture suited to the amount of light available. A larger aperture will gather more light and detail in darker settings.
3. Choose a lens with an automatic iris for outdoor cameras or settings where light will vary. A direct-drive lens requires that the camera have circuitry to control the iris. A video-drive lens can convert a signal from the camera for iris operation.
4. Decide on the range of distance that objects in view will need to be in sharp focus. This is called depth of field. You can create a larger depth of field with a wider angle lens, or with more light and a stopped down aperture.
5. Inspect your camera to determine which of the two standard lens mounting systems it uses. A "C" mount lens has a distance of 17.5mm between the lens and the CCD chip, while the "CS" mount has a distance of 12.5mm.
Tags: focal length, lens with, angle view, depth field, lens focal, lens focal length, more light
