Zeiss Wide Angle 25mm F/2 Distagon T* ZF.2 Series Manual Focus Lens for Nikon F (AI-S) Bayonet SLR System. Exceptionally fast f2.0 maximum aperture provides superb low-light capabilities Chromatic aberrations on this lens have been virtually eliminated, thanks to a special optical construction and selection of optical glass. Two aspheric lens surfaces correct distortion and image field curvature, and the floating elements design creates high imaging performance, regardless of the distance of the subject. The almost circular design of the aperture produces an exceptional "bokeh", beautifully reproducing the out-of-focus areas of the image. The ZF.2 lenses are an enhanced version of the ZF lenses. They feature an electronic interface (CPU) which enables the ZF.2 lenses to support all important operating modes such as shutter priority, aperture priority and programmed auto exposure or manual exposure settings even on non-AI compatible camera housings.