GSK-99

The Type 99 Ultra Small Aerial Camera (GSK-99) entered service with the Imperial Japanese Army in 1940. Unlike the standard Navy Type 99 and Army Type 100 models, the GSK-99 had interchangeable roll holder backs for 120 film. The camera has a wind up mechanism that triggered both film advance and cocked the shutter, allowing for rapid shooting of up to six images. In total, ten 6×6 images can be fit on a 120 roll of film. The GSK-99 film advance does not compensate for picture spacing. The first two frames may overlap if the film is not loaded correctly, and the spacing between the images will in-crease progressively.

The Tōkyō Kogaku-built GSK-99 was equipped with a fixed focus 75mm f=3.5 Simlar lens, while the Konishiroku-built GSK-99 was fitted with a fixed focus 75mm f=3.5 Hexar lens, set in a Compur-type Seikosha shutter.

The protective camera case allowed for the camera and two pre-loaded roll holders, as well as filters and spare rolls of film. The roll holders had a white Bakelite plate affixed to the back that allowed the photographer to add notes (in pencil) to the images taken on he roll. The camera could be operated hand-held or, with the removal of the wooden handles, could be fit-ted to the aircraft frame and then operated with a remote release, thus generating overlapping frames suitable for 3D interpretation

In total, about 3,000 units may have been built by Tōkyō Kogaku and Konishiroku. Annual production figures are unclear, but it seems that Tōkyō Kogaku produced as few as 187 units in 1941^[1]. The two models are apparently distinguishable by the nature and placement of the labels and the paint finish. From the limited number of cameras seen, it would appear that the Tōkyō Kogaku model has a grey to brown crinkle paint finish with metal tags, while the Konishiroku model has a smooth paint finish (grey, dark green) with Bakelite tags