Tokyo Kogaku Topcor-S 5cm f/2

Tokyo Kogaku Topcor-S 5cm f/2 LTM

The Tokyo Kogaku Topcor-S 5cm f/2 LTM is a Japanese Leica screw-mount standard lens made for Leotax and other L39 rangefinder cameras. Tokyo Kogaku, later known internationally as Topcon, was one of Japan’s important postwar optical manufacturers, and its Leica thread-mount lenses are generally regarded as uncommon, well-made collector lenses [1]. The 5cm f/2 was sold as a normal lens option with Leotax rangefinder cameras during the 1950s and early 1960s [2].

The lens uses a 6-element, 4-group double-Gauss optical design, with collector sources often describing the Topcor-S 5cm f/2 as a Biotar-type normal lens[3]. It has a Leica screw mount, rangefinder coupling, 40.5 mm filter thread, manual aperture control, and a focusing lever. LegacyCamera measured one later black-finish example at 255 g, with a 41 mm extension from the camera body at infinity focus, while Lens DB records the Panda variant at 280 g and 10 diaphragm blades[4]. Because barrel material and finish changed across variants, weight and handling can vary by version.

For LeicaLensList, this entry should be kept separate from the Topcor 5cm f/1.5, Topcor 5cm f/1.8, Topcor 5cm f/2.8, State / Simlar / Topcor 5cm f/3.5, and fixed-lens Topcon rangefinder camera lenses. The Topcor-S 5cm f/2 is especially relevant to Leica-compatible collecting because it combines LTM compatibility, Leotax system history, multiple distinctive finish variants, and a less common Japanese alternative to Canon, Nikon, and Leitz 50mm lenses of the same period.

History

Development and Launch

Tokyo Kogaku produced Leica L39 lenses before and after the Second World War, later expanding its postwar rangefinder lens production in cooperation with Leotax cameras. The Topcor-S 5cm f/2 appears in Leotax-era references from about 1954 and was available on Leotax F, T, K, FV, TV2, and T 2L models according to the Leica Copies reference cited by LegacyCamera. Lens DB also places the plain Topcor 50mm f/2 LSM around 1954, with later Topcor-S variants documented from 1957 and 1958.

Production Evolution

Collector sources describe several external generations of the Topcor 5cm f/2 L39 lens. L39camera notes three main exterior versions, with the first generation in chrome-finished brass, a rare intermediate version, and a later version with black aperture and focusing rings and more aluminium components. RangefinderForum separates the Topcor-S 5cm f/2 into all-chrome, Panda, and black/silver aluminium variants, with documented serial examples suggesting all-chrome production around the 210034 to 218847 range, Panda examples around 217984 to 220100, and black/silver examples around 540253 to 552843.

Special Variants

The main known variants are the all-chrome Topcor-S 5cm f/2, the Panda version, and the later black/silver aluminium version. The all-chrome version is usually associated with heavier chrome-over-brass construction, the Panda version uses a similar body style with contrasting finish, and the later black/silver version has a redesigned aluminium barrel and shorter focusing throw. Some collector discussion also distinguishes an earlier plain Topcor version before the Topcor-S engraving became standard.

Collector Notes

Collectors should verify the exact front-ring engraving, serial number, barrel type, finish, focusing lever, aperture ring style, filter thread, rangefinder coupling, and close-focus scale. Later versions commonly focus to 1 m, while early Type 1 Lens DB references list 3.5 ft, so close-focus distance should be checked on the actual copy. The Topcor-S 5cm f/2 should not be confused with the Topcor 5cm f/1.5, 5cm f/1.8, or 5cm f/2.8 LTM lenses. Common condition checks include internal haze, cleaning marks, coating wear, oil on aperture blades, stiff helicoid grease, missing focusing-lever parts, and mixed or converted barrels.