Ultrafast lenses – the Zeiss Planar 50mm f/0.7

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The quintessential vintage ultra-fast camera lens is the Zeiss Planar 50mm f/0.7. It was developed in 1961 for a specific purpose, namely to photograph the dark side of the moon during the NASA Apollo lunar missions. Only 10 lenses were built, one was kept by Zeiss, 6 went to NASA and 3 were sold to director Stanley Kubrick. Kubrick used the lenses to film scenes lit only by candlelight in the movie “Barry Lyndon” (1975).

There is a similarity, at least in the double-Gauss optical design – it is essentially a Gauss front with two doublets glued together and a rear group which functioned as a condenser. (copies of optical diagram). The 50mm f/0.7 Planar was designed by Dr. Erhard Glatzel (1925-2002) and Hans Sauer. It is supposedly based on an f/0.8 lens designed by Maximilian Herzberger (1900-1982) for Kodak in 1937. Looking at the two schematics, they look quite similar. The idea is to take the 70mm f/1, and by adding a condenser, brute-force the lens into a 50mm f/0.7. The condenser actually shortens the focal length and condenses the light – in reality adding a ×0.7 teleconverter that gives 1 f-stop.

But this lens has an interesting backstory. According to Marco Cavina, who has done a lot of research into the origin of this lens (and others), the design of this lens was derived at least in part from lenses designed for the German war effort. During WW2, Zeiss Jena designed a series of lenses for infrared devices to be used for night vision in various weapons systems. One such lens was the Zeiss UR-Objektiv 70mm f/1.0. The design documents were apparently recovered during Operation Paperclip from the Zeiss Jena factory before the factory was occupied by the Soviets and then provided to the new Zeiss Oberkochen.

The design went through four prototypes before achieving the final configuration [1]. The final scheme was optimized on an IBM 7090, which had been in operation since the late 1950s. The lenses were used on a modified Hasselblad camera.

  1. Glatzel, E., “New developments in the field of photographic objectives”, British Journal of Photography, 117, pp.426-443 (1970)
  2. https://wlpa.auction2000.online/auk/w.object?inC=WLPA&inA=20200729_1055&inO=329

Further reading:

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