[Canon] JS (Popular Model with Slow Speeds) | Film Cameras | Nov. 1939
The camera features slow shutter speeds ranging from 1 second to 1/20 second and does not have a rangefinder. It is designed for close-ups, photomicrography, astrophotography, and other special applications that require slow shutter speeds. According to Canon records, only 50 units were produced, and other details, including the original price, remain unknown. Around 1939, Seiki-Kogaku began making its own lenses, creating a prototype Tessar-type 50mm f/4.5 lens (4 elements in 3 groups) and a Sonnar-type 135mm f/4 lens (4 elements in 3 groups) without rangefinder coupling. The name "Serenar" was chosen from in-company suggestions, likely derived from a name of a sea on the moon. It wasn't until 1947 that the company started producing usable lenses for its cameras.
Type
35mm focal-plane shutter camera
Picture Size
24 x 36 mm
Normal Lens
Nikkor 50mm f/4.5
Lens Mount
Threaded (non-universal)
Shutter
Two-axis, horizontal-travel focal-plane shutter with cloth curtains. Single-axis rotating dial for 1, 1/2, 1/4, and 1/8 sec., and single-axis rotating dial for Z, 1/20, 1/40, 1/60, 1/100, 1/200, and 1/500 sec.
Viewfinder
Reversed Galilean viewfinder. Focusing with distance scale.
Film Loading & Advance
After top plate removal, drop-in bottom loading. Advances with camera-top knob.
Frame Counter
Manually set from 0 to 39 at the base of the camera-top rewind knob.
Film Rewind
Camera-top knob
Dimensions & Weight
136.5 x 69 x 30.5 mm, weight unknown
