Summarit 50 mm f:1,5

Características

Código - SOOIA, SOOIA-M 11 120 LLC - 124
Producción - 1949-1960 < 74,643 ejemplares
Variantes - Wetzlar, ELC and Taylor-Hobson versions
Montura -Rosca M39 y Bayoneta Leica M
Angulo de visión diagonal: 45º

Diseño Óptico:

Número de lentes/grupos - 7 /5
Longtud focal efectiva - 28,4 mm
Posición de la pupila de entrada -

Intérvalo de enfoque: - 0,7 m a infinito
Escalas: en metros o pies
Campo visual mínimo:
Diafragma - f/1,5-f/16 con click, fijación infinito, diafragma manual tipo iris de 16 hojas
Montura de filtros: rosca hembra interna E41 o A43
Parasol: XOONS 12150;
Accesorios: Visores: VIOOH y SBOOI 12015
Longitud hasta la bayoneta -
Diámetro máximo -
Material: Latón cromado
Peso - aprox. 320 g.

Inscripción - Summarit f=5cm 1:1.5 Nr82XXXX Ernst Leitz GmbH Wetzlar

Diseño: Otto Zimmermann

Referencias

• Marco Cavina (1) (2)
  
• Mathew Osborne MrLeica.com:1954 Leica Summarit 50mm f1.5 (2)
  

Descripción

Iniciado por Erwin Puts

• Earlier type without IR mark, later ones with this mark. Early versions have same mount as Xenon, later a normal screw filter mount.
  
• Serial number #1.000.000 has been produced in 1952, October 24, and this was a Summarit.
  
• Focusing scale in feet and metric, not both.
  

There is much confusion about the origin of the Xenon and Summarit. During the 1930s many designers were studying very fast lenses for the miniature camera. Zeiss had commercialized the Sonnar 1:1.5/50 mm for the Contax and had a Biotar 1:1.4/50 mm for cine cameras. It was indeed for this application that most designs were optimize for, but the knowledge could be extended to 35 mm- cameras too. Berek also had calculated a double-gauss 1.5 design, but the many air-glass surfaces demanded coating which was not available. W.H. Lee from Taylor, Taylor and Hobson (TTH) had designed a 1:1.5/50 mm (based on his research of lenses for cine-cameras, the primary domain of TTH, that could be used on 35 mm cameras. Schneider had adopted this TTH-design and gave it the household designation for fast lenses: Xenon. Why Leitz chose the same design from TTH is not known. Presumably Leitz wanted such a high speed lens in their catalogue to stop photographers from defecting to Zeiss. The claim that the Leitz Xenon was manufactured at the Leitz factory cannot be supported because there are no documents in the library that refer to the Xenon. It is thus highly probable that the Xenon was made for Leitz at the Schneider factory. Eight versions have been identified for a total of 6500 allocated units. The last lenses were made in 1939 and the after-war-sales are from the pre-war supply, but presumably coated. This is a strange story: the number of units sold after the war is less than 100! Dismantling these lenses, coating every lens element and then assembling the unit again is very laborious and costly. Why Leitz should have done this when the Summarit could also be supplied is a big question. The earliest serial number of 270.001 is allocated in 1935 (in a small batch of 4 lenses, presumably a test production sample), but production started in 1936 with #288.001. Early versions had the “Taylor-Hobson US Patent 2019985” or “ Taylor-Hobson Brit. Pat. 373950” engraving on the bezel, but from 1938 this text was gone. The Xenon was a very expensive lens: in 1939 it was four times as expensive as the Elmar 3.5/50 and twice as expensive as the Summar 2/50 mm lens. Having a lens on the camera with a maximum aperture of 1:1.5 was not only a matter of prestige (see the high price), but allowed the photographer to take pictures in difficult situations, like dimly lit rooms in Eisenstaedt style. The low contrast of the lens and the presence of aberrations could be mitigated by under-exposure.

The performance of the lens at full aperture is limited by the high level of internal flare, that tends to lighten the deeper shadow areas in a picture. The quite dreamy and romantic atmosphere of pictures taken with high-speed lenses at wider apertures in those days is visible in many picture examples. The Xenon, when stopped down to medium apertures had acceptable performance, but then the Elmar would perform as good or even better than the Xenon.

The Summarit 1:1.5/50mm is a coated version of the Xenon. The factory records show that this time the lens was manufactured at the Leitz Werke. The last batch was made in Midland. The Summarit starts its life with # 491898 with a batch of 102 lenses (491898 - 492000) allocated, but it is not known how many have been manufactured.It seems to be identical in all respects to the Xenon (but added the anti-reflection layers), as the factory records indicate. Produced in considerable quantities (75.000), and with a not too high price (same price level as Summicron DR!), it was a commercial success, which may explain the superlative words in the Leitz sales brochures.

The anti-reflection coating as a tool in the lens designer toolbox is effective when the design is optimized for the use of coating. Coating can reduce reflections and enhance the effectiveness of transmission, but only to a certain extent. The overall contrast at full aperture is still rather low. Generally the image quality of the Summarit is close to that of the Xenon, which should come as no surprise, as both shares the identical formula. These lenses might deliver better imagery when there used in the digital workflow where the inherent low contrast can be enhanced by unsharp masking.