(From Carl Zeiss lens literature)
Concentrated viewing -- high speed, detailed, distortion-free
This short, high-speed tele lens was specifically developed for challenging photography with SLR cameras. It impresses with its bright, clear viewfinder image and guarantees brilliant image quality even at full aperture, making it the ideal tool for both indoor and outdoor portraits.
The narrow depth of field at wide aperture permits visual silhouetting of the subject via the targeted use of background blurring. The special optical design and a diaphragm with nine blades and an almost circular geometry ensure excellent "bokeh" (aesthetic rendition of image areas out of the focus plane).
Distortion is practically non-existent. The lens is almost distortion-free, making it ideal for high-quality, analog and digital documentation photos.