The founder of the Helios 44 series is BTK (BioTar Krasnogorsky), renamed Helios 44. Zeiss Biotar 58mm f / 2 planar converted to Soviet glass. A quick overview of the lens series (links to full reviews are also available).
Lenses for SLR cameras with M42 screw connection. These lenses are installed on modern SLR and mirrorless cameras through the appropriate adapter. Read the article about adapters. The article is a guide to the Helios-44 series of lenses, but the history of the common name can be read at the link below:
About the Helios-44 lens series
The Helios 44 series of lenses was produced without any special changes in the optical scheme for almost half a century, and wore different indexes. At various times, production was launched at KMZ, Belomo, and the Jupiter Plant in Valdai. Early models had unpainted cases, so they are fairly easy to recognize. Year of issue lens, as a rule, since the 60s it was included in the serial number of the lens, and was imprinted in the first two digits.
Helios-44 is a standard lens for small format SLR cameras. High-aperture six-lens anastigmat. Coated optics or multilayer coating. It features an exact match of the visual and photographic planes of the image. Created on the basis of the Biotar 2/58 lens (Carl Zeiss Jena), originally called "BTK" - "BioTar Krasnogorsky.
The most popular KMZ lens, one of the most popular lenses in the world. It was produced in many varieties and variants at several enterprises. In the late 1980s, the production of Helios-44M-4 threaded MCs was transferred from Krasnogorsk to the Jupiter Valdai Plant (a specialized enterprise as part of the Krasnogorsk Plant), where lenses later began to be divided by resolution with the assignment of different indexes in ascending order. (MC Helios-44M-5, MC Helios-44M-6 and MC Helios-44M-7). Variants of "Helios-44" were also produced in Belarus at the MMZ (BelOMO).
Diagram of Soviet lenses Helios 44
The scheme is similar to Carl Zeiss Biotar 2 / 58mm... In fact, the history of the Helios-44 58/2 (Helios-44 58/2) series of lenses began with its recalculation.
Soviet lenses with the name "Helios" are made according to the Planar scheme of Dr. Rudolph (Paul Rudolph, 1896, Germany). Rudolph himself did not fully assess the possibilities of his scheme. They were discovered by the English optician H. Lee (Horace W. Lee), who in 1920 developed the Opic lens (Taylor & Hobson), which had an increased aperture ratio of 1: 2,5 (instead of 1: 3,3 for "Planar") at an angle of view of 50 degrees. Later, lenses of such a scheme were produced under various names by very many companies. "Helios-44", developed by Professor D.S. Volosov, is the most popular Soviet lens. Since 1958, he was put as a staff member on cameras "Start", then - to the "Zenith". (I.O.Baklanov, 1998)
Why does Helios-44 have a 58mm focal length?
To be used in SLR cameras, the lens must have a large rear focal section (roughly speaking, this is the minimum distance from the rear lens to the photographic material): then it is possible to place a mirror.
But this makes it difficult to develop normal and short-throw lenses, since often the maximum quality with the chosen scheme can be achieved only with a very small back focal length. Therefore, in order not to unduly reduce the quality, focal length "Helios-44" had to be increased to 58 mm instead of the standard 52 mm (the field of view is reduced from 45 to 40 degrees).
But even with such a rather small angle of view, the resolving power of "Helios-44" is clearly insufficient, such are the possibilities of this scheme (if one uses ordinary optical glasses). (I.O.Baklanov, 1998)
Technical characteristics of serial Helios-44
Focal length: 58 mm (58,60 mm) Relative aperture: 1:2 Field of View: 40 ° 28' Frame size: 24 x 36 mm Number of lenses / groups: 6/4 Anterior apical focal length: −34,25 mm Rear vertex focal length: 38,05 mm Distance from first to last surface: 39,80 mm First surface luminous diameter: ∅29,5 mm Luminous diameter of the last surface: ∅24,7 mm Resolution (0/10/20 mm) 3): 46/33/26 lines / mm Resolution according to technical specifications (center / region): Helios-44 - 35/14 lines / mm Helios-44-2 - 38/20 lines / mm Helios-44-7 - 36/17 lines / mm Helios-44M-4 - 38/19 lines / mm MC Helios-44M -4 - 41/20 lp / mm MC Helios-44K-4 - 42/21 lp / mm MC Helios-44M-5 - 41/20 lp / mm MC Helios-44M-6 - 45/25 lp / mm MC Helios -44M-7 - 50/30 lines / mm Light transmission coefficient: Helios-44 - 0,81 Helios-44-2 - 0,82 Helios-44-7 - 0,80 Helios-44M-4 - 0,80 MC Helios-44M-4 - 0,85 MC Helios-44K-4 - 0,85 MC Helios-44M-5 - 0,85 MC Helios-44M-6 - 0,90 MC Helios-44M-7 - 0,90 Geometric vignetting: 58% Color formula: Гелиос-44 (Старт) — 10--0--1,5 Гелиос-44 — 10--0--1,5 Гелиос-44-2 — 10--0--1,5 Гелиос-44-7 — 10--0--1,5 Гелиос-44М-4 — 10--0--1,5 MC Гелиос-44X-x — 11--0--0 Enlightenment type: single layer, chemical; multilayer (MC) Near Focus Limit: Helios-44 (Start) - 0,7 m other options - 0,5 m Aperture scale limits: 1:2–1:22, 1:2–1:16 Number of aperture blades: 13 (Start); 8 (Start, options without a diaphragm drive, Helios-44M); 6 - in the latest modifications (Helios-44X-4, -5, -6, -7) Working segment: bayonet Start - 42 mm Helios-44 - 45,2 mm Helios-44C-4 - 44 mm Other options - 45,5 mm Connections: lens with camera: Helios-44 (Start) - bayonet Гелиос-44 — M39×1 Гелиос-44-2 — M42×1 Гелиос-44-7 — M42×1 4) Гелиос-44М, Гелиос-44М-x — M42×1 Гелиос-44K-4 — байонетное, оправа K Гелиос-44C-4 — байонетное, тип C for screw-in nozzles: Гелиос-44 (Старт) — СпM40,5×0,5 Гелиос-44 — M49×0,5 Гелиос-44-2 — M49×0,75 Гелиос-44-7 — M49×0,5 Гелиос-44X-x — M52×0,75 for slip-on attachments: Helios-44 (Start) - ∅51 mm Helios-44 - ∅51 mm Helios-44X-x - ∅54 mm Dimensions: lens length without caps: Гелиос-44 (Старт) — 58 мм Гелиос-44 — 60 мм Гелиос-44-2 — 47 мм Гелиос-44-7 — 59 мм Гелиос-44X-x — 42 мм largest frame diameter: Гелиос-44 (Старт) — 60 мм Гелиос-44 — 60 мм Гелиос-44-2 — 60 мм Гелиос-44-7 — 62 мм Гелиос-44X-x — 64 мм Weight: Helios-44 (Start) - 0,23 kg Helios-44 - 0,23 kg Helios-44-2 - 0,23 kg Helios-44-7 - 0,35 kg Helios-44M - 0,3 kg (270 g ) Helios-44M-4 - 0,3 kg MC Helios-44M-4 - 0,3 kg MC Helios-44K-4 - 0,3 kg (258 g) MC Helios-44M-5 - 0,27 kg MC Helios -44M-6 - 0,27 kg MC Helios-44M-7 - 0,27 kg Year of development: presumably: November 1951, XNUMX Completion of ROC: Helios-44-M - 1972 Helios-44M-4 - 1981 Production: large-scale production Years of production: since 1958 (Start)
Varieties of lenses Helios-44
Helios-44 "White" M39
Helios 44 white or light - the first of the serial Helios of the 44 line. 8 or 13 aperture blades, M39x1 threaded mount, cases not painted, working length 45,2 mm. It is believed that these lenses are of better quality, as they were made from German glass. Single layer coating, manual iris control with preset ring. MDF 0,5 meters. Regular for mirror cameras Zenit-3, Kristall, Zenit-3M, interchangeable for cameras Zenith and Zenit-S. Development and release of KMZ.
Produced only for f \ a "Start" with a mount for it. Single layer coating, manual iris control, 13 or 8 aperture blades. The specific mechanism of the diaphragm drive device with a leading lobe, MDF 0,7 meters. Produced at KMZ. Separate articles about Helios with the "Start" mount: