There are a lot of features you need to look for when purchasing CCTV security cameras because they directly affect your surveillance system and how good your overall security is. CCTV lens is one of the aspects that requires serious consideration. Knowing which type of lens to choose for a specific situation will help you make an educated decision and enhance your surveillance and security properly.

Auto iris and direct drive lens are common choices when it comes to CCTV lenses. The difference between these two lenses is described below:

Auto Iris Lens

Auto iris lens is the type of lens that is electronically controlled. Because of this configuration, the spatial dynamic of the iris is easily controlled depending on the lighting level and the optimal quality imaging is obtained. So this makes auto iris lens suitable for situations where lighting conditions change continuously. No matter the lighting condition, you are guaranteed to get the best possible picture with an auto iris lens. Auto iris is applicable to both varifocal and fixed lenses. The lens is also an ideal choice when it comes to producing consistent video signals.

Cameras with auto iris are relatively costlier than manual or fixed iris because they use more advanced technology. But they are worth the cost because they are more suitable to recording in locations where you need automatic adjustments due to the lighting changes between sunlight and nighttime.

Many of the newer CCTV cameras these days come with built-in auto iris which is electronically configured, so you won’t need to take any steps. It is recommended that you inquire about the type of lens from your security integrator in order to make the best decision.

Direct Drive Lens

Direct drive lens is a type of lens that uses DC motor to control the iris of the camera. They are relatively cheaper than auto iris lenses so they are a better choice if your budget is tight. Direct drive lenses were introduced many years ago by the security camera market. It is one of the most popular and widely used auto iris technologies these days. Digital cameras have also adopted this technology due to the availability and popularity.

A direct drive lens basically uses a DC motor to move the aperture in one direction and then return the aperture to its original location (usually closed) via a spring. Direct drive lens depends on a reference signal to decide whether the iris should be opened or closed. The reference signal is compared with a control signal to do this job. The lens is opened if the amplitude of the control signal is higher, and it is closed if the control signal amplitude is lower. Because of this configuration, the iris keep on drifting until the control signal is updated again. This is due to the fact that the analog reference can never perfectly match the camera. Because of this reason, direct drive lenses are preferred when continuous imaging is required.