Pekka Buttler, 01/2026
Introduction
Sun Optical was a Japanese third‑party lens maker that produced interchangeable lenses and cine optics from the post‑war era through roughly the late 1970s, often as an OEM behind house brands and smaller import labels.
It later changed its name to Gotō Sun and appears to have disappeared into another company during the 1980s
Sun Optical Co., Ltd.
Sun seems to have had its origins in Kajiro Kōgaku Kenkyūjo (Kajiro Optical Laboratory), which was founded in July 1939 by Kajiro Hitoshi. This company initially sold its lenses under the K.O.L brand (likely short for Kajiro Optical Laboratory) and these lenses can be seen on many Japanese pre-war cameras – both on the first versions of the Mamiya Six as well as on LTM cameras. The company expanded operations in 1941 – likely in part due to military contracts – and changed names to Gojō Kōki Seisakusho. After the Japanese surrender in 1945 operations ceased. Whether due to a decree by occupation forces1 or other reasons is not known to JAPB.
The operations were however picked up soon by Sun Kōki K.K. and early Sun Kōki lenses used brand names that were obviously inherited from the K.O.L era (such as Xebec and Sola). In the 1950s, 60s and early 70s, the company used the English name Sun Optical Co., Ltd. and manufactured interchangeable lenses both for sale under its own ‘Sun’ brand as well as for various rebranders. Whether Sun also manufactured optics on contract to major brands is unknown, but not impossible.
Sometimes between the early 70s and 1981 the company changes its name to Gotō Sun and sometime during the 1980s Sun optical disappears from the lens making market. Several sites speculate that Sun Optical was absorbed into Goyo Optical Inc (which continues to today, albeit in a slightly different field)
Sun lenses?
During its time as an independent lens manufacturer, Sun Optics manufactured a range of interchangeable lenses for 135 format cameras as well as cine lenses. Some of these lenses were sold under the “Sun”, “Sun Opt.” and “Sun Optical” brands, but Sun is also known to have manufactured lenses for several rebranders, most notably Soligor.
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Footnotes
- Some Japanese optics companies that had taken contracts from the Imperial Japanese Navy or Imperial Japanese Army were shut down by the occupation forces pending investigation. Whether similar decisions cause the end of operations for Gojō Kōki Seisakusho is not certain. ↩︎