For macro photography with large magnification ratios, it's frequently better to use the lens in reversed position, with the bayonet facing the subject and the front lens facing the camera body. Often, the achievable image quality is better this way. Especially with wide-angle lenses, high magnification ratios can be achieved in reversed orientation.
To be able to reverse the lens, an adapter is required that has a male bayonet for mounting on camera body or bellows, and either clamps the front end of the lens from outside or is screwed into the filter thread.
When a reverse adapter is used, no automatic aperture setting is possible – if a lens is reversed with help of an adapter, the aperture has to be closed manually prior to exposure. This way, obviously no automatic exposure is possible. The metering has to be done by the stop-down (match-needle) method. For automatic closure of aperture to a preset value in reversed position, a further accessory is available, the Auto Ring with double cable release.
The original Konica Reverse Adapter is not screwed into the lens's filter thread, but clamps the front end of lenses with 55 mm filter thread diameter from outside. The necessary fastening screw is pointing upwards with the bayonet in locked position and protrudes quite a bit. Therefore, the original Konica reverse adapter cannot be used directly on the camera body, because the fastening screw will interfere with the prism housing of the camera body. If a direct use on the camera body is desired, the use of a third-party reverse adapter that screws into the filter thread or has the fastening screw in another position is inevitable. The original Konica reverse adapter can only be used together with extension rings or bellows.