What do the lens sizes of CCTV cameras mean?

The Cameras we sell have different focal length lenses which are expressed in millimeters. The smaller the number, the wider angle the lens. A 4mm lens is very wide angle (on a 1/3" CCD Chip, roughly 62 degrees horizontal viewing angle), whilst as we move up to 6mm the angle closes in and the image appears nearer. If you are not sure what focal length you require, you could choose one of our vari-focal CCTV cameras.

The size of camera’s
imaging device also affects the angle of view, with the smaller devices creating narrower angles of view when used on the
same lens. The format of the lens, however is irrelevant to the angle of view, it merely needs to project an image which will cover the device, i.e.;
the same format of the camera or larger. This also means that 1/3” cameras can utilize the entire range of lenses from 1/3” to 2/3”, with a
1/3” 8mm lens giving the same angle as a 2/3” 8mm lens. The latter combination also provides increased resolution and picture quality as only
the centre of the lens is being utilized, where the optics can be ground more accurately.

The focal length of the lens is measured in mm and directly relates to the angle of view that will be achieved. Short focal length provides wide
angle of view and long focal length becomes telephoto, with narrow angle of view. A "normal" angle of view is similar to what we see with our
own eye and has a relative focal length equal to the pick up device. The "computar" range calculator is simple device to use for estimating focal
length, object dimension and angle of view, alternatively the VM300 view finder gives an optical way of finding focal length.

The focal length of the lens is measured in mm and directly relates to the angle of view that will be achieved. Short focal length provides wide
angle of view and long focal length becomes telephoto, with narrow angle of view. A "normal" angle of view is similar to what we see with our
own eye and has a relative focal length equal to the pick up device. The "computar" range calculator is simple device to use for estimating focal
length, object dimension and angle of view, alternatively the VM300 view finder gives an optical way of finding focal length.