cameras OM-10 The OM-10 hit the markets in June 1979 at the same time as the OM-2N. The camera was a 35mm focal-plane shutter aperture priority AE SLR camera with an electronic shutter. Only aperture-priority AE was available with the camera unless the optional manual exposure adapter was installed. This allowed the setting of shutter speeds between 1s and 1/1000s, (bulb mode was also available). The camera was equipped with a fixed pentaprism viewfinder which contained an LED exposure indicator. The finder coverage was measured to be 93%. Exposure control was aperture priority AE using center-weighted light metering. Film speeds of the camera range from ASA 25 to ASA 1600. Film winding was done by using the film-wind lever located on the top right of the camera. Film rewinding was done manually using the film-rewind crank located at the top left. The camera body measured 136 × 83 × 50 mm and weighed approximately . OM-20 The OM-20 (sold in the United States as the OM-G) was essentially a refinement of the OM-10, replacing that model's rather tricky mode switch with one that was easier to use. The OM-20 also had a built-in shutter-speed dial, a mode display in the view finder and a much stronger winding mechanism which permitted it to be used at 5 frames per second on the OM Motor Drive 2. The shutter magnet and release system had other minor design improvements. OM-30 Essentially an OM-20 with auto-focus capability. With a normal lens there were lights in the view finder to help the user with manual focusing. When used with a motor drive or winder unit and the M-In Focus Trigger cord, the lens could be pre-focused on a specific point. As soon as an object moved into that focus zone the camera would trigger a shot. A special motorised 35-70mm autofocus lens was also available at the time, but is now very rare. OM-40 A further refinement of the OM-20 with features that were more of interest to serious photographers. It had a lighter, slightly more modern and ergonomic body design. It also had an early form of matrix metering, and a mirror lock-up facility. This was activated when the self-timer was switched on, a feature still rarely found in non-high-end cameras. Also known in some markets as the OM-PC, the OM-40 had a program mode that automated the selection of both the aperture and