My boy was GIVEN an Olympus OM2n by a widow lady with 50mm f1.8 and 70-150mm Zuiko lenses and he has had no trouble with the exposures; I showed him how to compensate for subjects against a lighter or darker than normal background or white subjects using the 'auto' exposure setting. If you are using the 'manual' setting are you sure you are lining up the needle in the centre of the + and - signs in the viewfinder correctly ?