There is a Wikipedia for cameras: Camerapedia. One of the things they list is my first SLR: the Olympus OM-30. The on-off switch is on the right in this image: protruding part on the ring around the film rewind knob. This meant that it was really easy to turn the camera on as you were putting it back into its case, and so completely run down the five very expensive button cells that it needed to operate.

Tags: Photography, Canon, Nikon, DSLR, History, Museum, Interesting Stuff, Olympus