The ultra-wide Zeiss Distagon T* 18mm f/3.5 ZF.2 Lens for Nikon F-Mount Digital SLR cameras is a precision prime lens that provides excellent image performance over its entire image range from 0.98' (0.3 m) to infinity. Combined with the legendary Zeiss T* anti-reflective coating, the Distagon T* 18mm f/3.5 delivers brilliant pictures even under difficult lighting conditions. This professional lens, when mounted to a digital SLR using a DX-type sensor, has an effective focal length of 27mm (35mm format).
The new ZF.2 lenses are an enhanced version of ZF lenses. They feature an electronic interface (CPU) that enables support of all important camera operating modes such as shutter priority, aperture priority and programmed auto exposure or manual exposure settings on non-AI compatible camera housings. Photographers no longer have to set the parameters in the camera menu as the lens now transmits standard data such as focal length, speed and the aperture setting to the camera. This data can then be viewed in the EXIF data of each picture.
Furthermore, silver fork coupling is not available. For this reason, you cannot use light metering on older cameras (F, F2, Nikkormat, etc.). The ZF.2 lenses have a mechanical lock on the aperture ring to lock the aperture ring at the lowest setting and prevent unintentional adjustment while taking pictures.
For technical reasons, these lenses do not have a half-step aperture lock between the lowest (stop position) and the second lowest aperture setting. This guarantees reliable recognition of the automatic position. The lowest aperture on ZF.2 lenses is colored orange to emphasize the automatic position of the aperture ring.