FAQ
		What is the difference between video drive and direct drive lenses?

Auto Iris lenses require a driving circuit to control the operation of the iris aperture under changing light conditions. The driving circuit can be located either in the camera or lens.

On a video drive lens the driving circuit is found within the lens itself. If, however you're using a direct drive or DC lens the circuit can be found within the camera. To control this function on a video drive lens, controls can be found on the lens and for a direct drive/DC lens on the camera. The majority of cameras will accept both types of auto-iris lenses with the operation of a switch. Some cameras will only accept either one or the other.

FAQ
		Can I put a CS-mount lens on a C-mount camera?

Cameras can be fitted with either a 'C-mount' or 'CS-mount' lens mounting. The difference between C and CS mount equipment is the distance between the flange of the lens and the focal plane of the lens (where the CCD sensor must be positioned). On C-mount lenses the flange back length is 17.5mm and on CS-mount lenses it is 12.5mm.

A C-mount lens may be used on a CS-mount camera with an adaptor ring but a CS-mount lens cannot be used on a C-mount camera, since correct focus cannot be acheived.

Some C-mount cameras do allow you to swap the whole mount from C to CS.

FAQ
		I have fitted my lens to my camera and cannot get it to focus. What am I doing wrong?

Ensure the format of the lens is the same format as the camera, for example if you have a 1/3" lens then you should have a 1/3" camera (this is not always the case but as a general rule you can put a higher format lens on a lower format camera but not the other way round). If you have the same format combination, then ensure you have removed the C/CS ring on the camera (this is a small ring fitted to the front of the camera , which is used to extend the distance between the lens and the camera when using a higher format lens to a lower format camera (e.g 1/2" and 1/3")) this is not required when using same format combinations.