Industar 61
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The Industar 61 was produced at the FED factory in Kharkov, Ukraine. It is a "normal" lens for M39 (Leica screw mount) and M42 (Pentax screw mount), with a focal length from 52-55mm, depending on the production run. It has four elements in three groups. The iris may have between six and ten blades depending on the version of the lens, and a range of apertures from f/2.8 to either f/16 or f/22. It is commonly found on rangefinders made by FED and Zorki. Its brand name Industar refers to the class of similar 4-element/3-group lens constructions of the whole soviet photo-optical industry.
The Industar 61 L/D is possibly the most highly regarded lens for Ukrainian Leica copies apart from the 35mm Jupiter-12. In an L/D or L/Z version of this lens, the L indicates that the lens has (slightly radioactive) Lanthanum in it, and D indicates M39 mount while Z indicates M42 mount. Most examples are multi-coated and are marked as such with MC. Some Industar 61 L/Z bear the logo of LZOS, probably having been made by that company.
Optical formula from OPAL database
Cистема-Индустар-61 f'=53 2w=46 1:2.8 КОНСТРУКТИВНЫЕ ПАРАМЕТРЫ ОПТИЧЕСКОЙ СИСТЕМЫ N Радиусы Осевые Световые Марки Показатели преломления пов. кривизны расст. высоты стекол L= .589300 .434050 .656280 ВОЗДУХ 1 19.099 7.500 9.300 СТК9 1.742397 1.761307 1.738057 2 57.540 1.500 8.000 ВОЗДУХ 3 -80.170 1.600 8.000 Ф4 1.624200 1.647216 1.619252 4 16.106 3.800 7.400 ВОЗДУХ 5 84.140 1.500 7.600 ЛФ9 1.579999 1.600239 1.575648 6 19.099 7.000 7.700 СТК9 1.742397 1.761307 1.738057 7 -40.460 8.070 ВОЗДУХ ПРЕДМЕТ: Удал. размер Y = -23.00000гр.мнсек S0= .000дптр от вх.зрачка ИЗОБРАЖ: Близ. размер Y'= .00000 плоск. SI= .000мм от пл.Гаусса ДИАФР. : ND= 4 плоскость SD= 2.0000 мм передн. апертура= 9.3000 мм
Links
- Matt Denton's Industar 61 L/D lens page
- Matt Denton's HOWTO on cleaning and lubing the I-61
- Servicing an Industar 61 L/D lens, at Pentax Manuals
An Industar 61 L/D (M39 mount) image by Michael Gatchell (Image rights) |