Summicron 50 mm f:2,0 (III)

Características

Código - 11 817-negra - 11 819-negra - LLC - 120
Producción - 1968-1979 < 44,029 objetivos
Montura -Bayoneta Leica M

Angulo de visión (diagonal, horizontal, vertical): 35 mm (24 x 36 mm) : 47º, 40º, 27º, - for LEICA M8 (18 x 27 mm) : 36º, 30º, 20º,

Diseño Óptico:

Longtud focal efectiva - 51,7 mm
Posición de la pupila de entrada 28.0 mm
Número de lentes/grupos - 6/5

Intérvalo de enfoque: - 0,7 m a infinito
Escalas: en metros y pies combinada
Campo visual mínimo: 35 mm, approx. 277 x 416 mm
Ampliación:

Diafragma - f/2-f/16 con click y valores intermedios, diafragma manual tipo iris de 10 hojas

Montura de filtros: rosca hembra interna E39, rosca macho con limite para parasol
Parasol: 12459
Accesorios:

Longitud hasta la bayoneta - 50.0 mm
Diámetro máximo - 51 mm
Material: Aluminio anodizado, latón y vidrio óptico
Peso - aprox. 240 g

Inscripción - LEITZ WETZLAR 2XXXXXX SUMMICRON 1:2/50
ELCAN f/2 50 MM 276-00XX (for the KE-7A 1972-1974 ca.500 lenses)

Diseño: Walter Mandler

Referencias

Marco Cavina

Descripción

During the 1960s many changes in emulsion technology, lens design criteria and photographic requirements ushered in the era of high acutance technology. Research had indicated that high contrast at the limit of the resolving power of the film-emulsion provided better image quality than a high resolving power with lower contrast. The Leitz Summicron-R and the Nikkor-H 2/50mm were probably the first lenses to be designed according to this rule. Both were six element lenses and these designs replaced the previous seven-element constructions, which were generally of lower contrast. The Summicron, introduced in 1969 was a Midland design and followed the design principles of the Summicron-R, also a Midland design. The Summcron for the rangefinder camera has a significantly higher performance than the predecessor. It now has medium to high contrast already at maximum aperture and excellent definition of very fine detail when stopping down to medium apertures. One of the reasons for this improvement is the reduction to six elements, including an air lens that separates the lens elements 4 and 5 with a thickness of 0.07 mm. This very small thickness cannot be seen in the formal drawings of the lens, but for illustrative purposes the public diagrams have an exaggerated distance between these elements. A second reason for the enhanced performance is the wider diameter of the last element that could help the designer to reduce some aberrations.

Overall the lens is an outstanding performer, but in that period of time the rangefinder system was overshadowed by the reflex cameras and this Summicron sold in relatively low numbers. The exact amount is difficult to extract from the documentation, but should be lower than 40.000 units.