"The Zeiss Touit 50mm f/2.8M Lens (Sony E-Mount) is a moderate telephoto prime lens designed for use on cameras with APS-C format sensors and as such provides a 35mm-equivalent focal length of 75mm. This lens is compatible with Sony E mirrorless cameras and supports all camera functions, including autofocus and exposure control. With a 1:1 magnification ratio, it offers close-up macro capability and its minimum focus distance is 6"". An f/2.8 maximum aperture is effective in low light and provides shallow depth of field focus. A complex floating lens system ensures a uniform length when focusing and provides consistently sharp performance. The optical design includes two aspherical elements and two anomalous partial dispersion elements which minimize lateral and longitudinal chromatic aberrations. Its nearly circular 9-blade diaphragm combined with depth of field control enables imaging with a soft, pleasing, out-of-focus background. It is an ideal lens for portraiture, still-life, landscape and numerous other photo and video applications. The physical construction of the lens features a sleek, all black, metal lens barrel with rubberized control rings for smooth precision when working with manual focus. A metal bayonet mount ensures accurate alignment. For optimum compatibility of Touit lenses on Sony NEX cameras it is recommend to use the latest firmware (1.02 for NEX-5R/NEX-6 and 1.03 for NEX-7 or higher). The firmware can be downloaded from the Sony website."