Biotar

The Biotar is a sechslinsiges lens for film and photo cameras. Its basic design follows the Gaussian double lens. Biotar constructions already reached in the 1920s, a high light intensity.

Just as with the planar, the four lenses of the double Gauss lens be extended to each side by a further outer lens in Biotar. The inner two pairs of lenses are cemented as the Planar. The xenon lens 1925 developed by Albrecht Wilhelm Tronnier for Schneider-Kreuznach followed the Zeiss designer Willi Merté in the introduction of an important asymmetry: field-side (front ) three-piece lens group was done a total greater than the group located behind the iris. Further, the two outer condenser lenses are each of larger diameter than the two inner pairs of lenses. The first steps in this direction was Horace Williams Lee Taylor Hobson Company gone.

The Biotar has for decades offered by Zeiss, often with a considerable initial light intensity of 1:2 at a focal length of 58 mm ( a calculation of 1936 for KB - SLR ). For even higher light levels, such as are required for movie recording ( 1:1.5 or 1:1.4 ), these lenses but could only be used in exceptional cases (eg for portraits: Biotar 1:1.5 / 75 mm ( 1938) ). Zeiss then brought out a revised Biotar 1:1.4 / 25 mm for 16 mm films and in 1930 a Biotar 1:1.4 / 50 mm for 35 mm film cameras.

However Biotar lenses do not have to follow the basic structure described here. Willi Merté also designed an extremely light strong R Biotar 1:0.85 for X-ray cameras. Such special lenses were used for photographic fixation of weakly fluorescent screen image of the former X-ray equipment. The R- Biotar follows a Petzvalobjektiv under construction.

Swell

• Taunus rider: " Early fast lenses ", accessed on May 14, 2011.
• Kingslake, Rudolf ( 1989) The History of the Photographic Lens. Academic Publishers Inc.

• Lens type ( Photography )
• Brand name
• Zeiss lens