The Biogon 21mm f/4.5 is an ultra-wide-angle lens for the Contarex. Manufactured by Carl Zeiss Oberkochen, it is a legendary lens that also earned an outstanding reputation in its version for the Contax IIa/IIIa.
Introduced in 1959, it remained on sale until 1962. This particular example, with a serial number in the 3.44 million range, was manufactured in 1964. Total production was 4,000 units. Its actual measured weight is 276g.
The optical design consists of eight elements in five groups. Because it employs a symmetrical, non-retrofocus design, the rear element protrudes deeply into the camera body.
The camera mirror must be locked up when using this lens, so focusing is done by estimating the subject distance. The dedicated viewfinder is mounted on the Contarex accessory shoe for framing. The distance scale is marked in meters, with markings down to 0.5m. Although the focusing helicoid itself stops at 1m, the lens’s extensive depth of field allows subjects as close as 0.5m to be in focus even at maximum aperture.
The barrel shows only the slightest signs of use and is very beautiful. The plating has a dazzling brilliance, giving the lens an air of dignity worthy of a flagship Zeiss lens from its era.
Fully overhauled in June 2026. Thanks to meticulous servicing, both the aperture and helicoid now operate very smoothly.
There was considerable haze at first, but after cleaning, the glass is now beautiful, with no haze or noticeable cleaning marks. When held up to a strong LED light, very slight coating deterioration can be seen, but it is at a level that should have virtually no effect on photography.
The original metal 21-35mm lens hood, front cap, and deep aluminum rear cap are included. All are engraved Zeiss Ikon, and for this lens, these are the correct accessories.
