Famous 13 blades Helios 44 58mm f/2 2/58mm, Excellent Rare Lens, moun m39/M42 Zenit

This lens was designed at Krasnogorsky Mechanical Plant. This is a representative of vast "Helios-44" family, that was based on German Carz Zeiss Jena Biotar 2/58. Firstly it has a name "BK" - Biotar from Krasnogorsk.

Optical scheme was calculated in 1951 at State Optical Institute (USSR). Lens was produced in 1958-1994 at three plants: KMZ, BelOMO, Jupiter. This is one of the most popular lenses in the world.

This lens was default for SLR cameras "Zenit-3", "Zenit-3m", "Crystal" and optional for "Zenit" and "Zenit-C". This lens had either 8, or 13 aperture blades. Early lenses had unpainted aluminium body, later lenses were black


Note: it is a lens for SLR with mount M39x1/45.2, it will not work if set on rangefinder with M39x1/28.8 (LTM) mount. They have different flange focal distance.


Number of lenses - 6 in four groups, Biotar

Angle of view - 40o

Number of aperture blades - 13

Limit of aperturing - 1:2 (max), 1:16 (min)

Resolving power - (centre/edge) 35/14 lines/mm

Minimal distance of focusing - 0.5 m

Type of thread - M39х1/45.2

Type of thread for the nozzles - M49x0,75 mm

Dimensions (mm): 61*60*60

Focal distance - 58,60 mm.

One-layered anti-reflection coating

CONDITION :

Lenses are  new! Used very little! Optics defect-free! Focus running smoothly!