The Zuiko Macro 20 mm f/3.5 lens and the Zuiko Macro 38 mm f/3.5 lens do not have the normal OM lens bayonet mount. Instead, they have a small screw-thread mount (RMS – Royal Microscopical Society – thread, 0.8″ diameter, 36 t.p.i.), the same as microscope objectives. They require the PM-MTob adapter to enable them to be fitted to the Auto Bellows.
|Olympus OM Objective Lens Mount PM-MTob|
The PM-MTob can also be used to adapt any standard microscope objective to the Olympus OM bayonet fitting.
This adapter is not intended to be attached direct to a camera body.
|US catalog no.||104-220|
Only one version is known.
Adapters that allows the Zuiko Macro 20 mm f/3.5 lens and the Zuiko Macro 38 mm f/3.5 lens to be fitted to Canon, Contax, Minolta, Nikon, Olympus OM, Pentax and 42×1 mm cameras are available from the Italian seller Adriano Lolli either as eBay seller lolliadriano or direct from his website. They no longer seem to be available from Beljan Manufacturing in the USA.
Instructions were not provided with the PM-MTob.