The Schneider 35mm f/5.6 Apo-Digitar XL Lens with Schneider Electronic Shutter is an extremely wide angle large format lens specifically designed for use with digital backs, which require extremely resolved, color correct image circles of a smaller size. Digital backs also benefit from use at larger apertures to avoid image degradation from diffraction, and this Apo-Digitar XL can comfortably be used at its maximum aperture at all times.