A12 M-Mount | Lenses | Conclusions | Links

On this page, I collect information about the Ricoh GXR A12 M-mount expansion unit that allows to use manual lenses with the Leica M bayonet on the Ricoh GXR.

 

A12 M-Mount

A lot had been speculated in the photo forums about the Ricoh GXR M-mount expansion unit, a unit without a lens that features a Leica M bayonet and an APS-C size sensor (CMOS, total pixels: approx. 12.9 million, effective pixels approx. 12.3 million - more or less the same as for the two other A12 units). The unit appeared on the roadmap that Ricoh secretly revealed at Photokina 2010, was officially announced by Ricoh in August 2011, and eventually hit the market on September 9, 2011 - although in small quantities only.

M mount expansion unit      M mount expansion unit

Photo: Ricoh A12 M-mount expansion unit

The expansion unit has features that are meant to support manual focusing as well as a wide range of lenses with Leica M bayonet:

*) With other units, the focus assist can also be used with AF, which does not make much sense in my opinion...

In addition, the unit has two shutters, a mechanical and an electronic one:

The electronic shutter is probably meant as a competition to the silent Leica shutters. It has to be selected in the scene modes and is not suitable for moving objects (it can be used for achieving special effects, though...).

Another specialty of the M-mount unit is that is has no or only a very weak AA filter, resulting in much more detail as many posters report in the forums...

This unit allows to capture videos in HD 720p format (no AF).

 

Lenses

The A12 M-mount unit accepts manual lenses with Leica M bayonet. There is no mechanical or electric coupling between lens and the body. Other manual lenses can be used with adapters. For example, Novoflex offers a wide range of such adapters (adapter finder; ditto in German), however, with a steep price tag. The "number one" choice for adapter is probably an adapter for using M39 Leica lenses (for example older Leitz, Voigtländer, or Zorki lenses) with the unit.

(In)compatible Lenses

Ricoh publishes a list of approved lenses at the bottom of their M-mount unit page (Mounting Check Results for Each Lens). In addition, they supply a "check device" with the M-mount unit that you can use to check whether the rear part of a lens protrudes too far so that it might damage the sensor. There is also a list of (in)compatible lenses at Ricohforum that is continually updated and much more useful than Ricoh's list.

    

Photos: The check device that Ricoh supplies with the M-mount expansion unit

Among the manufacturers who offer Leica M lenses are:

 

Conclusions

With its APS-C sensor, the A12 M-mount expansion unit offers an image quality comparable to that of DSLRs - just like the preceding A12-50 and A12-28, with which it (nearly) shares the sensor. Like with its predecessors, image quality is hampered by visible banding in night scenes, which is caused by the CMOS sensor. However, I did not check that in detail yet.

Many forum posters praise the lack of an AA filter, resulting in finer details that its A12 companions can deliver. Of course, this is confounded with the lenses that are being used on the unit. Many M bayonet lenses are old designs or based on old designs, which show quite different image characteristics than new ones.

So, the A12 M-mount expansion unit opened up a whole new field for experimentation. This may be one of the reasons, why the units has so eagerly been adopted - and, of course, also as a "cheap", but high-quality Leica replacement or as an additional body for existing Leica gear.

 

Links

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24.03.2012