Types of Lenses Used in CCTV Cameras

CCTV cameras use several kinds of lens, and the kinds are usually distinguished by their view, by their adjustment, or by the camera they fit. A buyer who can tell the kinds apart can describe a need more precisely, and can judge whether a lens offered actually matches that need. This post explains the kinds in plain language, using only the categories listed by Hangzhou Ai Ke Electronics Co., Ltd.

The post states no model and no specification for any kind, because no model specification is published on this site. Its purpose is classification, not recommendation: it helps a buyer name the kind of lens being discussed, so that the further questions, about the exact lens, its specifications and its terms, can be asked properly.

Kinds distinguished by view

The first way to distinguish CCTV camera lenses is by view: how wide or narrow the picture is. A wide-angle lens gives a wide view, covering a large area from one position, with less detail per part of the scene. A narrow lens gives a narrow view, covering a small area or a distant point, with more detail for the part it covers. Most CCTV lens choices begin with this distinction, because the view decides what the camera can show at all.

Between wide and narrow lie the ordinary views that suit most CCTV jobs: a room, a yard, an entrance, a corridor, a shop floor. Those ordinary views are not a separate kind of lens but the middle of the wide-to-narrow range, and a buyer should describe the scene rather than reaching for a label. A view that is wide for a small room may be narrow for a large yard, so the scene and the position matter as much as the label.

A view that changes is a separate kind, covered below under adjustment. But even a changing view moves within the wide-to-narrow range, and the buyer should still describe the two ends of the range needed: the widest view the job requires and the narrowest view it requires. A lens that covers one end but not the other has not met the job, however well it covers the end it does reach.

Kinds distinguished by adjustment

The second way to distinguish CCTV camera lenses is by adjustment: whether the view can be changed after fitting. A fixed lens keeps one view, set at manufacture, and cannot be changed without refitting a different lens. A varifocal lens lets the view be adjusted, by hand at the camera, so that the installer can set the view after the camera is up. A motorized varifocal lens lets the view be changed during use, by motor, without a visit to the camera.

Adjustment is useful where the view is uncertain, where one camera model must serve several positions, or where the view must change during use. It is not useful where the view is known, fixed and unchanging, and where simplicity and repeatability matter most. The varifocal versus fixed guide on this site explains that trade-off, and buyers should read it before assuming that adjustment is always worth having.

Zoom lenses belong in this group as well, since zoom names the application of changing the view. A CCTV camera with a zoom lens is a camera whose view can be changed between an overview and a detail view, and the CCTV zoom page on this site covers that application. The words varifocal and zoom overlap, and a buyer should describe the need, whether the view must be set once or changed during use, rather than arguing about which word applies.

Kinds distinguished by camera

The third way to distinguish CCTV camera lenses is by the camera they fit. Ordinary CCTV cameras use general CCTV lenses, the most general kind on this site. Industrial cameras use C Mount industrial lenses, reflecting the C Mount mount family and the working environments those cameras serve. Board cameras and small modules use M12 board lenses, reflecting the compact fitting those cameras require.

Distinguishing by camera matters because fitting comes first: a lens that does not fit the camera cannot be used, whatever its view or adjustment. A buyer who knows the camera can narrow the kinds at once, while a buyer who knows only the view may be offered a lens for the wrong camera family. The inquiry should therefore name the camera alongside the view and the adjustment need.

A fourth distinction cuts across the others: low distortion lenses, distinguished by their behaviour rather than their view, adjustment or camera. Low distortion matters where shapes in the picture must stay true, for measurement or analysis, and the low distortion category on this site covers it. A low distortion lens may still belong to another kind as well, such as a CCTV lens or an industrial lens, and the inquiry should name both the distortion need and the camera family.

How to use the kinds in an inquiry

Use the kinds to describe the need, not to choose the lens alone. A useful inquiry names the camera, the scene, the view needed, whether the view must change, and whether distortion matters, and then asks which kind, and which model if any, fits that combination. That description lets the supplier answer specifically, rather than guessing from a single label.

Then confirm the exact lens, if one is offered, together with its specifications, minimum order quantity, lead time and price, and confirm compatibility with the camera and mounting arrangement, in writing, before payment. Confirm which documents are supplied with the order. On this site the certificate position is: Certificates available upon request. No certificate detail is stated here, and none should be assumed from any other statement on the site.

A note on naming the kind you need

Naming the kind is the beginning of an inquiry, not the end of it. A buyer who can say the camera, the view, the adjustment need and the distortion need has described the lens well enough for a supplier to answer specifically. A buyer who can only say a single kind, without the camera or the scene, has described a label, and the supplier must guess the rest. The kinds in this post are therefore best used as vocabulary for a fuller description, not as a shortcut that replaces one.

Frequently asked questions

How many kinds of CCTV camera lens are there?

It depends on how you count. By view, wide and narrow; by adjustment, fixed, varifocal and motorized; by camera, CCTV, industrial and board; and by behaviour, low distortion. Most real lenses combine one from each group.

Is one kind best?

No kind is best in general. The best kind for a job is the one that fits the camera, covers the scene, gives the view needed and keeps shapes true where that matters.

Can I choose a kind from this post alone?

You can name the kind you need. The exact lens, its specifications and its terms must still be confirmed with the supplier.

Related pages

• CCTV Camera Lenses
• Lens Used in CCTV Camera Guide
• Varifocal Lenses
• Low Distortion Lenses