Security cameras have different lens types with distinct advantages and uses. Here are some short definitions plus some pros and cons to each type:

Security Cameras With Varifocal Lens (Zoom Lens)

Security cameras featuring varifocal lens will allow the focal length of the lens to varied. This feature is most commonly called a “zoom” lens. Security cameras with zoom lenses or varifocal lenses should come with an auto iris feature (an electrically controlled iris) to be truly useful.

• A zoom lens you monitor larger outdoor areas with one camera. The combination of auto iris and varifocal means you can monitor a large area and selectively zoom in only when motion is detected.
• A zoom lens security camera lets you easily adjust and optimize for available light conditions
• Security cameras with zoom lenses are especially applicable in locations such as outside a main door or gates, outside parking lot, or other situations where the lighting conditions continuously change

Security Cameras With Fixed Lens
Security cameras with  fixed focal length lenses cannot zoom its focus is fixed. Fixed lens security cameras are a good low-cost solution in certain circumstances. A security camera with a fixed focal length lens generally allows more light to pass through the lens at a given focal length than a varifocal, or zoom lens. This can be important in low-light situations to avoid blurred video that is useless.

• Security cameras with fixed lenses allow fast action-stopping shutter speeds to be used in low-light situations. Fixed focal length lenses are sometimes the only solution for night-time video
• Security cameras with fixed lenses are best suited for fixed lighting conditions (indoors) such as shopping centers, schools, libraries, and offices
• Video from fixed lens security cameras is usually sharper than their zoom counterparts
• Security cameras with fixed focal length lenses are usually less expensive than their zoom counterparts