zuiko85
Veteran
Reverse mount rings were available for the OM mount lenses. Consisted of a 49mm to OM mount that screwed into the filter thread and a piece that went on the lens mount with a dummy pin to make the lens stop down to whatever aperture it was set at. Focus fixed at one point only if mounted directly on the camera. There are a number of cheap adapters on ebay, some costing less than $5 but they have no provision for stopping the lens down. The real limitation of reverse adapters however is that, while mounted directly to the body the reproduction ratio is fixed.