Olympus OM-4 Ti camera body

The Olympus OM-4 is an interchangeable-lens, 35 mm film, single lens reflex (SLR) camera; manufactured by Olympus Optical Co., Ltd. (today Olympus Corporation) in Japan, and sold as OM-4 from 1983 to 1987 and as OM-4Ti from 1986 to 2002. The OM-4Ti also introduced a new electronic flash-control system. Normally focal-plane shutters are limited in their maximum flash synchronization speed, because of the way they provide fast shutter speeds – timing the second shutter curtain to close more quickly after the first shutter curtain opens. This causes a narrowing of the slit "wiping" the exposure on the film. In effect, a horizontal focal-plane shutter made of cloth is only fully open and usable for flash exposure up to 1/60s. Any faster and a typical one-millisecond flash burst would only partially expose the film - the part open to the slit. The OM-4Ti overcame this problem by having the new Olympus F280 Full Synchro flash pulse its light continuously over 40 milliseconds, long enough to illuminate the slit as it crossed the entire focal plane, even at shutter speeds as fast as 1/2000s. There is, however, a concomitant loss of flash range.