I am thinking for buying the Voigtlander Heliar 75mm f/1.8 Lens and would like to confirm that it is compatible with the Ricoh GXR Mount A12 module. Can you confirm?
As far as I know, anh Leica M mount lens, this included, should work fine.
from the an online camera review
"The ability to resuscitate classic manual focus lenses has been one of the unexpected side-effects of the development of mirrorless camera systems. Ricoh has responded to this trend by introducing the Mount A12 module for its GXR system. This module, featuring a Leica-style M mount, allows the fitting of a wide range of lenses onto a GXR body for the first time.
The GXR system may originally have aimed to offer optimized combinations of lens, sensor and processor, but the customer demand for the ability to mount other lenses was too much for Ricoh to ignore. There is, after all, a certain appeal to shooting a well-built metal lens on a small camera, but very few of us are willing to move back to film in order to experience it, or to spend considerable sums on a digital Leica. Ricoh clearly isn't content to sit on the sidelines as the mirrorless systems begin to respond to this pent-up demand.
The use of the Leica M-mount brings flexibility in two respects. In part because it is no longer under patent, and also thanks to its age, there are a wide range of lenses available for the M-mount. These include Zeiss, Voigtländer, Konica, Minolta and Rollei lenses, as well as native Leica designs. Just as crucially, because the M-mount has one of the shortest distances from the mount to the imaging plane, there's room to fit an adapter allowing the use of a vast range of other lens types."