The body of my OM40 (called the OM-PC in the USA) showing
the pattern printed on the shutter curtains which are read
by rearward facing silicon blue cells to provide the off-
the-film exposure calculation. With the OM-2n being aimed
at professional photographer sales, the OM40 was meant for
the amateur consumer. Each camera is delightful to use and,
using the same lenses, produces indistinguishable results.