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EXPLANATION OF THE FOCAL LENGTH OF A LENS
What does the "mm" value mean to me?

1.8mm to 2.3mm - SUPER WIDE ANGLE: This focal length is only used when you need to see a lot of area - I mean a lot! Before you say "that's what I want", keep in mind that the more area you see, everything in the picture is smaller on the screen and may take on a fisheye or curved look. Super wide lenses are typically more expensive.

2.7mm to 3mm - WIDE ANGLE: Good for most applications and will work well inside or where your subject is close to the camera. These lenses have an "angle of view" between 90 and 100 degrees. Place a camera with this focal length in the corner of a room and you will see the whole room except for the area directly below the camera.

3.5mm to 6mm - NORMAL ANGLE: Good for most applications except for small rooms, close up subjects, and wide coverage areas. Angle of view is between 50 and 80 degrees.

8mm to 100mm - TELEPHOTO NARROW ANGLE: Good for longer distance applications. Need to see the gate at the end of the driveway or the rollup door across the warehouse? This is the lens range you will most likely need. The Angle of view is between 37 and 3 degrees.

Need a recommendation? This is our favorite lens that works great for about 95% of all applications (the Fujinon YV2.8x2.8LA-SA2L).

Need to see that gate from 800' away? No problem - give us a call. We have lenses that will allow you to see subjects from a great distance.


EXPLANATION OF LENS APERTURE - What does the "f/#" mean to me?

Simple - the lower the "f" number, the more glass the lens has. More glass allows more light to reach the CCD sensor in the camera allowing it to perfom better in lower light conditions. So a f/1.0 lens will "see" better in low light than a f/1.4 lens etc.. Have plenty of light in your scene 24/7? Then don't worry about the aperture number.


EXPLANATION OF AN "IR" CORRECTED LENS:

Most types of artificial lighting emit some level of invisible infrared light. When the scene is bright, this is not a problem because the automatic iris inside the lens closes down and consequently, the image's range of sharpness increases. At lower lighting levels however, this infrared light will shift the focus range of the lens and will cause a picture to look a little fuzzy. An IR corrected lens compensates for this phenomenon and produces a sharp image under all types/levels of lighting.


EXPLANATION OF AN ASPHERICAL LENS:

A regular lens utilizes glass elements that are perfectly round throughout the entire surface of the lens. The picture area of a camera, however, is rectangular so the corners of a picture can sometimes be not as sharp as the center of the image. An aspherical lens is made using a special process that essentially flattens out the glass in certain spots to allow a picture that is just as sharp in the corners as it is in the middle. It can also help brighten the image in the corners as well. The special glass is slightly more expensive but well worth it if you seek the sharpest possible images.

Be sure to check out our Lens Calculator .