Sony ISSUE 3 manual Lens Format, Cameras with Built-in Lens

Selecting the Correct Lens

Another characteristic of lenses is the ‘depth of field’ (see illustration). If a lens is focused on an object there will be a certain area of sharp focus in front of and behind the object. The depth of this area of sharp focus is controlled by three factors: the focal length of the lens, the distance from the lens to the object and the F stop.

Lens Format

The lens format relates to the camera format, 1/3 inch, 1/2 inch, 2/3 inch. There are two lens mounting systems. Most CCTV cameras have a ‘C’ mount, although many now use a ‘CS’ mount. ‘C’ mount cameras are not able to use ‘CS’ lenses, however adaptors are available.

To avoid the complexities of lenses with automatic irises, manufacturers have developed ‘electronic shutters’. These achieve the same light adjustment with simpler, fixed iris lenses. The CCD iris common to most Sony CCTV cameras automatically controls image exposure by electronically adjusting the incoming light levels.

Cameras with Built-in Lens

Some cameras are now available with a built-in lens. Sony manufactures a 1/3 inch colour camera with an integral 5.4mm - 64.8mm zoom lens (SSC-CX34P) which can be used in place of the conventional camera and motorised lens set-up. This saves installation time and the resultant set-up is lighter, allowing the use of more compact camera housing and pan and tilt head.

For more information contact the Sony Business Information Centre: 01932 816340

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