The OM2 and 4 both work that way. The only difference is that the 4 increased the longest autoexposure time (2 minutes on the 2's and 4 minutes onthe 4's, as I recall). This allows the OM's to produce beautiful night exposures with just the push of the shutter button. I've taken shots that range from 15 seconds to several minutes, lit by candles, firelight or starlight and every time they have come out perfectly exposed.
Originally Posted by Les Sarile