|Black Chinon CS|
image by Gustavo Torossi (Image rights)
The Chinon CS has an in-built light meter that was designed to be powered by a 1.35 volt PX13 mercury cell providing a constant power source. Due to environmental reasons, mercury batteries are no longer readily available in many countries. Suitable replacements include a 1.5 volt Alkaline battery (together with an adjustment in the camera's film speed setting), a 1.35 volt WeinCell zinc/air battery, or a number of other PX13/PX625 battery substitutes.
image by Bracket ツ (Image rights)