OM-2

This camera went on sale in 1975. It features an automatic exposure (AE) system with an aperture-preferred shutter. The OM-2 also had the world's first TTL direct metering system, which measures light reflected off the surface of the film. This allowed exposure control during shooting, and automatic TTL strobe adjustment using a specially designed strobe. To develop the TTL direct metering technology, Olympus collected 35mm film from throughout the world and measured the reflection ratios for each roll. The results were used to determine the density of printing on the shutter curtain.