Varifocal Lenses

A varifocal lens is a lens whose focal length can be adjusted, so the field of view can be changed after the lens is fitted, rather than staying at the single setting of a fixed lens. This page covers the Varifocal/Zoom Lens category as listed by Hangzhou Ai Ke Electronics Co., Ltd.

The value of adjustment is practical: an installer can fit the camera, look at the picture, and then widen or narrow the view until the scene is covered the way the buyer wants. That flexibility is why varifocal lenses are common where the exact view cannot be fixed in advance, or where one lens must serve scenes that change.

What this category covers

This category covers varifocal lenses in general. Narrower pages on this site pair varifocal adjustment with particular jobs: motorized varifocal lenses, where the adjustment is driven rather than set by hand, and varifocal lenses for security cameras and for CCTV cameras, where the pairing describes the camera the lens will serve.

The comparison guide on this site, varifocal versus fixed lens, explains the trade-off in plain terms: adjustment brings flexibility, while a fixed lens brings simplicity. Reading that guide alongside this category page helps a buyer decide whether adjustment is actually needed, since not every installation benefits from it.

Where varifocal lenses are used

Varifocal lenses are used with CCTV cameras, security cameras and other cameras where the installer needs to set the view on site. Examples include a camera watching an entrance where the useful view depends on the exact mounting position, a camera covering a yard where the boundary to be watched is only clear once the camera is up, and a camera that must first give a wide overview and later be narrowed to a particular point.

Motorized varifocal lenses extend the same idea to cameras whose view must change after installation without a visit to the camera. The motorized pairing page describes that need separately, so buyers who need remote adjustment can follow that route.

What to confirm before ordering

Confirm how the adjustment is made for the exact lens concerned, whether by hand or by motor, and confirm that the adjustment range suits the scene. Confirm the model, specifications, minimum order quantity, lead time and price for the quantity required, and confirm compatibility with the buyer's camera.

Documents should be confirmed at the same time. Certificates available upon request. No certificate detail is stated on this site.

Frequently asked questions

What is the difference between varifocal and zoom?

The two words overlap in everyday use. On this site, varifocal names the adjustable category in the company's listed range, and zoom pages describe the zoom application of the same idea. Ask the company which term applies to the exact lens offered.

Do I always need a varifocal lens?

No. If the view is known in advance and will not change, a fixed lens may be simpler. The varifocal versus fixed guide explains the choice.

Can the view be changed after installation?

That depends on the exact lens. Confirm how adjustment works for the lens offered, and whether it needs a visit to the camera.

Related pages

• Motorized Varifocal Lenses
• Varifocal Security Cameras
• Varifocal CCTV Cameras
• Varifocal vs Fixed Lens Guide
• CCTV Zoom Lenses