Konishiroku Hexar 50mm f/3.5

Konishiroku Hexar 50mm f/3.5

Among the standard lenses that Konishiroku, the predecessor of Konica, produced in Leica screw mount during the 1950s, the Hexar 50mm f/3.5 was the most modest and the most widely seen. It used a Tessar-type optical layout of four elements in three groups, the same formula fitted to the Konica I and IIB cameras of the same period [1]. Rather than selling it directly to the public, Konishiroku supplied the lens to other makers, so it became the affordable standard option on a range of Japanese Barnack-style bodies rather than a lens marketed under its own name [1].

The lens has an all-chrome collapsible barrel clearly modelled on the Leitz Elmar 5cm f/3.5, with red arrows on the collapsing tube to indicate the locking direction [1]. The aperture scale runs from f/3.5 to f/22 on the side of the front section, and the diaphragm sits behind the second element [1]. Focusing is by a tab with an infinity lock, the focus scale engraved in feet [1]. The mount is the standard 39mm Leica thread, used on contemporary Leica and Leica-copy rangefinders. Published collector references record a filter thread of 34.5mm and a focus scale reaching about 3.3ft; figures cited for filter size and close-focus distance vary between sources [1].

The Hexar 50mm f/3.5 was adopted as a standard lens for several cameras: the Chiyotax IIIF in 1955, the Honor S1 in 1956, and the Melcon from 1955, where it served as a cheaper alternative to the Nikkor-H 5cm f/2 [1]. It was also offered on some versions of the Leotax and reportedly on the Nicca, and it could be bought separately through Shōwa Kōgaku, maker of the Leotax, for ¥11,000 [1]. Lens serial numbers have seven digits and have been observed across the 1311xxx to 1322xxx range, although it is not certain whether these form a single continuous sequence [1].

Optical qualities

Rendering

Documented rendering information for this lens is limited, and most sources describe it through its design rather than measured performance. As a coated four-element Tessar type of the mid-1950s, it belongs to a family known for good central sharpness at moderate apertures and a compact, simple construction, which is consistent with its role as an economy standard lens [1]. Specific, well-supported claims about its bokeh, flare resistance, distortion or digital behaviour are not available, so they are best left unstated rather than assumed.

History

Development and Launch

In October 1954 Konishiroku showed several lenses under development in Leica screw mount at exhibitions held in three Tokyo department stores [1]. The following year the company released a group of three standard lenses, beginning with the collapsible 50mm f/3.5 Hexar, followed by the faster Hexanon 50mm f/1.9 and the exotic Hexanon 60mm f/1.2 [1]. The Hexar occupied the entry level of this short line, sharing its Tessar-type formula with the lens on Konishiroku's own Konica leaf-shutter cameras [1].

Production Evolution

The lens was still offered at its original price as late as the summer of 1957 [1]. After the market for screw-mount rangefinder cameras and lenses collapsed in the 1960s, surplus stock is said to have been cleared at heavily reduced prices, with the Hexar 50mm f/3.5 reportedly sold for as little as ¥1,500 by a Tokyo shop [1].

Special editions

No major factory special editions of the Hexar 50mm f/3.5 are widely documented. Two related but distinct items are recorded, however. A separate collapsible Hexanon 50mm f/3.5, said to use five elements, is known only as an experimental example and was never put into production [1]. In addition, the maker of the viewfinder-only Chiyoca built a different "Hexar 50mm f/3.5" by mounting Konishiroku enlarging lenses on a self-made focusing helix, a conversion whose rangefinder coupling cam was reportedly not properly adjusted for Leica-standard focal length [1].

Collector Notes

Buyers should distinguish the collapsible Leica-mount taking lens from the modified enlarging-lens "Hexar" found on the Chiyoca, which is a different and unofficial conversion [1]. The genuine taking lens is all chrome with red collapsing arrows, a focus tab and infinity lock, and seven-digit serial numbers in the 1311xxx to 1322xxx range [1]. At least one auctioned example has been noted with a non-original barrel made in Germany, so originality of the barrel and engravings is worth checking [1]. Because several published figures for filter size and minimum focus distance disagree, it is sensible to measure the filter thread directly rather than rely on a single quoted value [1].

Sources

• [1] Camerapedia. Konishiroku lenses in Leica screw mount. https://camerapedia.fandom.com/wiki/Konishiroku_lenses_in_Leica_screw_mount