FED FED-36 100mm f/6.3

FED-36 100mm f/6.3 L39

The FED-36 100mm f/6.3 is a rare prewar Soviet telephoto lens made for FED Leica-type rangefinder cameras in M39 screw mount. It belongs to the early FED accessory lens system, alongside the standard FED 50mm lenses and the uncommon FED 100mm finder. Sovietcams lists the FED 6.3/100 as a FED M39 lens released from 1937, with a 10cm focal length, f/6.3 to f/36 aperture range, 1m close focus, 4 elements in 2 groups and a 24 degree angular field [1].

The lens is compact for a 100mm rangefinder telephoto. FotoUSSR describes the FED-36 as a fully functional 100mm long-focus lens and notes that its length at infinity is about 5.5cm, but because that value is given as approximate it should not be used as a clean database dimension. The same source records a 4/2 optical formula, approximately 28.8mm working distance, 10 aperture blades, M39 x 1 camera connection, about 37mm slip-on attachment diameter and 228g weight [2].

Compatibility requires caution. Prewar FED cameras and lenses were made to Leica-type dimensions, but early FED production tolerances were not always identical to Leica standards. Some examples may need individual adjustment to focus accurately on Leica screw-mount bodies or Leica M bodies with an L39-to-M adapter. The lens should therefore be treated as a historically relevant Leica-thread-mount rangefinder lens, but not assumed to be perfectly calibrated on every Leica body without testing [2] [3].

Optical qualities

Rendering
Reliable formal testing is limited. The lens is uncoated and uses a simple 4 element, 2 group design with few glass-air surfaces. FotoUSSR notes that the FED-36 has no coating, while a collector sample report describes surprisingly contrasty performance at full aperture despite the lack of coating [2] [7].

Sharpness
Published user evidence is mixed but generally positive for a prewar compact telephoto. A Flickr sample report describes the lens as usable wide open and states that stopping down does not necessarily improve resolution much, partly because shiny aperture blades can increase internal reflections. This should be treated as sample-level evidence rather than a universal optical test [7].

Contrast and flare
The lens is uncoated, so flare, veiling and internal reflections are important collector and user considerations. FotoUSSR specifically notes uncoated optics and shiny aperture blades. Fotohandel Delfshaven tested one copy on a digital Leica and reported surprisingly high contrast for an old uncoated lens, but performance will depend heavily on sample condition and lighting [2] [5].

Digital use
The FED-36 can be adapted to Leica M and mirrorless digital bodies through L39 adapters, but rangefinder accuracy should be tested carefully. At 100mm, even small calibration differences are more visible than on a 50mm lens. FotoUSSR also notes that focusing accuracy with a rangefinder at 100mm leaves little margin, which supports checking infinity and near focus on the exact camera body [2].

History

Development and Launch

The FED-36 was part of the prewar FED system of interchangeable lenses and accessories. Sovietcams lists the FED 6.3/100 as released by FED since 1937 and identifies it as an uncommon M39 lens. FotoUSSR notes that observed FED-36 examples are marked as products of the Dzerzhinsky Kharkiv NKVD Combine, a company name used from December 1938 to January 1941, suggesting that known production may have been concentrated in that period [1] [2].

Production Evolution

Public information about exact production volume is limited. FotoUSSR states that archives were lost during the war and that production years and output numbers are not firmly known. Sovietcams distinguishes the standard PT8110 FED 6.3/100 from later or altered PT8115 and PT8120 examples, which it describes as changed-body versions that are not rangefinder-coupled and possibly remade from regular lenses [1] [2].

Special Editions/Variants

No commemorative factory special edition is documented. Collector-relevant variants include the standard rangefinder-coupled FED-36 6.3/100, the very rare FED 5.9/100 prototype, and altered or remade non-rangefinder-coupled 6.3/100 examples. The FED 5.9/100 is a separate ultra-rare prototype lens and should not be merged with the FED-36 production entry [1] [6].

Collector Notes

Collectors should verify the front engraving, M39 mount, rangefinder coupling, serial number, infinity focus, near-focus accuracy, original FED 100mm accessory finder, caps and leather cases. Important condition checks include haze, cleaning marks, fungus, aperture blade reflections, stiff focusing, loose mount fit and whether the lens has been modified or remounted. A complete set with the original FED 100mm optical finder is more desirable than the lens alone [2] [4].

Special editions

No confirmed factory special edition is currently documented.

Known collector-relevant variants and related versions include:

• FED-36 100mm f/6.3, standard prewar FED M39 rangefinder-coupled telephoto lens.
• FED 100mm accessory viewfinder, not a lens variant, but an important original accessory for collector completeness.
• FED 5.9/100 prototype, ultra-rare separate prototype lens, not the same database entry as the FED-36.
• PT8115 changed-body 6.3/100, reported by Sovietcams as not rangefinder-coupled.
• PT8120 changed-body 6.3/100, reported by Sovietcams as not rangefinder-coupled and possibly remade from a regular lens.
• Non-standard or remounted M39 examples, should be documented individually before being treated as Leica-compatible.

Sources

• [1] Sovietcams. Fed 6.3/100 mm. https://mikeeckman.com/sovietcams/index0f50.html?_m_e_id=5&_menu_i_id=543&tmpl_id=567&tmpl_into=middle
• [2] FotoUSSR. Pre-WWII Lens FED-36 6,3/100 & viewfinder FED 100 mm. https://fotoussr.com/en/lenses_en/pre-ww2-lens-fed-36_en/
• [3] Wikipedia. FED camera, FED 1 lens type information. https://en.wikipedia.org/wiki/FED_%28camera%29
• [4] MW Classic Cameras. Fed 100mm f6.3 all chrome L39 Rangefinder coupled Portrait lens + Fed 100mm Optical shoe finder. https://mwclassic.com/product/fed-100mm-f6-3-all-chrome-l39-rangefinder-coupled-portrait-lens-fed-100mm-optical-shoe-finder-with-makers-rear-lens-caps-uncommon-erly-pre-war-lens/
• [5] Fotohandel Delfshaven. FED 6.3 / 100mm lens in Leica screw mount. https://fotohandeldelfshaven.nl/product/fed-6-3-100mm-lens-in-leica-screw-mount/
• [6] Sovietcams. Fed 5.9/100 MM. https://mikeeckman.com/sovietcams/indexc38d.html?_m_e_id=5&_menu_i_id=542&tmpl_id=566&tmpl_into=middle
• [7] Alexander Kraus. FED f:6.3 / 100mm, model designation FED-36. https://www.flickr.com/photos/alexander_kraus/52873976917