The 135mm f/2.0 ED UMC Lens for Nikon F Mount with AE Chip from Rokinon is a manual focus telephoto prime lens useful for portraiture and all medium telephoto applications. Its fast f/2.0 maximum aperture is effective in low light and enables shallow depth of field control. With a rounded 9-blade diaphragm, shallow depth of field imaging will be rendered with pleasing out-of-focus highlights. Compatible with both FX and DX format DSLRs, it provides the 35mm focal length equivalence of 202.5mm when used on DX cameras. Its minimum focus distance is 2.6'.The Nikon F-mount version of this lens features an AE chip that provides auto exposure metering in Auto, Program, Aperture-Priority, Shutter Priority, and Manual modes as well as a focus confirmation in the camera's viewfinder when focus has been reached manually. The optical design includes one extra-low dispersion lens element to control chromatic aberration, contributing to sharp, color-accurate imaging, and each of its lens elements features Ultra Multi-Coating to improve light transmission and reduce ghosting and flare. An internal focus system prevents the front end from rotating which allows more effective use of variable filters.