Nippon-Kogaku Nikkor-HC 5cm f/2 Collapsible

Nippon-Kogaku Nikkor-HC 5cm f/2 Collapsible

The collapsible Nikkor-HC 5cm f/2 is the earliest form of what became Nippon Kogaku's most prolific rangefinder normal lens, and the one most likely to be mistaken for a Leitz optic at a glance. Its six-element, three-group formula descends from the prewar Zeiss Sonnar 5cm f/2, a design Nippon Kogaku adapted after Zeiss patents passed to Japan in the aftermath of the Second World War [1]. The "H" in the name denotes the six-element construction and the "C" marks the lens as coated. Both the S-mount and the Leica Thread Mount collapsible versions were produced in a brief, parallel run, and both are now considered rare and expensive among collectors [2].

The barrel collapses by roughly a centimeter, a modest but real reduction in carrying length that sets it apart from the later rigid LTM Nikkor 5cm f/2 [2]. The machining quality is high, with closely fitted parts that recall an era of small-batch, hand-finished production, and the lens carries a noticeable heft for its size [2]. Focusing uses a long throw suited to precise rangefinder work, and earlier examples have an infinity-lock button that doubles as a focusing finger grip and helps when unscrewing the lens from the body [2]. The aperture ring is clickless, predating the click-stop convention, and the barrel seats into its collapsed and extended positions with a faint but positive detent [2]. With ten blades the iris stays close to round. The lens couples to the rangefinder on Leica Thread Mount cameras and on the many postwar Japanese screw-mount bodies such as Nicca, Tower and Leotax that were frequently sold bundled with Nikkors [1][2].

Identification rests on details that distinguish this collapsible model from its successors. It precedes both the rigid LTM Nikkor-HC 5cm f/2 and the later black-banded "Blackbelt" version, the latter using more aluminum internals and dropping the red "C" once coating had become universal [3]. Early collapsible examples carry thinner, lighter engraving than later, bolder typefaces, and late examples were supplied with a collar to prevent collapse, a configuration collectors call the "hybrid" version [2]. Because production spanned a period of glass-supply transition, the optics went through small recalculations as German glass gave way to Japanese equivalents, so minor running changes exist within the type [2].

Optical qualities

Rendering Documented impressions describe a classic Sonnar character: smooth, slightly swirly background blur with gentle, "polite" focus transitions rather than abrupt ones, and good central sharpness even wide open [2]. Out-of-focus highlights show some outlining and a mild soap-bubble tendency at f/2, becoming cleaner and rounder by about f/2.8 [2]. The optics are shared with the S-mount sibling, which exhibits noticeable vignetting wide open that improves by f/2.8, and modest, visible geometric distortion on straight lines [4].

Flare resistance Flare resistance is weak by modern standards, as is typical of an uncoated-era optical layout carried over with early coatings; strong light sources in the frame reduce contrast [2].

History

Development and Launch Nippon Kogaku entered the Leica Thread Mount market in the desperate postwar years when Japan needed export currency and when many domestic makers produced Leica-copy bodies without the capacity to build their own lenses [2]. Supplying LTM Nikkors let those cameras be sold complete, and the lenses gained wider attention after favorable press exposure [2]. The S-mount and LTM collapsible 5cm f/2 lenses date from the early years of Nikon's consumer camera business, with serial-number evidence placing some examples around 1948 [2]. The broader Nikkor-HC 5cm f/2 family remained in production until roughly 1962 [3].

Production Evolution The collapsible LTM version was followed by a rigid LTM model that added its own helicoid allowing very close focusing while uncoupled from the rangefinder, and later by the black-banded variant with simplified, lighter aluminum internals [3][4]. Within the collapsible run itself, small optical recalculations accompanied the shift from German to locally sourced glass, and late units gained an anti-collapse collar [2].

Collector Notes The collapsible LTM Nikkor commands a premium for its rarity, with one repairer reporting the batch numbered fewer than about two thousand examples; the S-mount equivalent can fetch even higher prices [2][3]. Buyers should check for haze and early balsam separation between cemented elements, both reported on surviving examples, as well as the usual oil migration onto the aperture blades [2][5]. Confirming whether a lens is an early collapsible, a late "hybrid" with collar, or one of the later rigid or black-banded versions helps establish what is actually in hand, since the names are easily conflated [2][3].

Sources

• [1] Casual Photophile. Nikon Nikkor H C 50mm F/2 LTM Lens Review: A Leica Alternative That's More Than Just a Copy. https://casualphotophile.com/2017/09/05/nikon-nikkor-h-c-50mm-f2-ltm-lens-review-a-leica-alternative-thats-more-than-just-a-copy/
• [2] Richard Haw's Classic Nikon Repair and Review. Repair: Nikkor-H•C 5cm f/2 LTM (collapsible). https://richardhaw.com/2019/03/24/repair-nikkor-h%E2%80%A2c-5cm-f-2-ltm-collapsible/
• [3] Richard Haw's Classic Nikon Repair and Review. Nikkor-H•C 5cm f/2 (Leica Thread Mount). https://richardhaw.com/2024/02/18/nikkor-hc-5cm-f-2-leica-thread-mount/
• [4] Richard Haw's Classic Nikon Repair and Review. Repair: Nikkor-H•C 5cm f/2 (S-Mount). https://richardhaw.com/2017/05/28/repair-nikkor-h-c-5cm-f2-rf/
• [5] Victory Camera. Nikon Nikkor H.C 5cm 50mm f2 LTM Rare Collapsible Screw Mount Lens. https://www.victorycamera.com/products/nikon-nikkor-h-c-5cm-50mm-f2-ltm-rare-collapsible-screw-mount-lens-w-bubble