Description
The lens is a very important component of any camera. The lenses offered here fit our box style cameras. The lens is attached by simply threading the lens onto the camera body. Each lens has two adjustment knobs, one to adjust the focus and the other adjust the zoom.
(Our dome cameras are all shipped with the lens factory pre installed)

Manual Iris vs Auto Iris
The manual iris lens has a fixed iris while the auto iris lens self adjusts as lighting conditions change. In general a manual iris lens can be used where the lighting conditions are always the same. If the lighting conditions change then an auto iris lens is a better choice.

What mm lens
Lenses are identified by the mm (milimeter) or range to which the lens may be focused. In general, a lower mm number produces a wider angel view and a shorter zoom range. A higher mm number produces a narrower view and further zoom range. If you want to watch a wide area then a lower mm lens is in order. If your subject is further away such as across a parking lot or if you wich to capture a close up of the cash register then a higher mm range is likely a better choice.

If in doubt use this handy lens calculator.