This multi megapixel resolution lens supports cameras up to 5 megapixels. The long focal length magnifies objects from far away for unobtrusive security. This lens allows the user to digitally zoom in up to 16x. It is a high quality lens designed to allow the installer to take full advantage of the high resolution of HDTV and multi megapixel cameras. The focal length is 9 - 40 mm and the lens fast aperture (F-number) is 1.5. The Theia Varifocal Telephoto Lens 9-40 mm with DC-iris is recommended for use with the AXIS P1346/-E and AXIS P1347/-E Network Cameras. The lens is day/night corrected and therefore no adjustments will be needed when the IR-cut filter of the camera disengages.