In this blog post I will share a couple of unprocessed full resolution shots taken with the Voigtländer Apo Lanthar 90mm f/3.5 SL for M42 mount. Although not a comprehensive lens review, it should give some idea of the performance of this lens, and the amount of vignetting (or lack thereof) to expect on the 44 × 33 mm medium format sensor.
The lens was produced by Cosina from 2002 to 2007 and is available in Canon FD, Nikon Ai-S, Minolta MD, Olympus OM, Pentax PK-A/R, Contax/Zeiss CY, and M42 mounts. It features a double Gauss design with a single element of anomalous partial dispersion.
In general, the lens has great sharpness in the middle, which drops off slightly towards the periphery. However, stopped down, it is acceptably sharp across the frame. The extreme corners are not very sharp on GFX, to be expected. There is some pincushion distortion. Longitudinal chromatic aberrations are generally decently corrected but still visible in some shots.
Flare resistance is quite poor, and loss of contrast or large lens flares are possible.
Thanks to its compact size, it is very pleasant to bring around and its close focus ability makes it excellent for food photography. Bear in mind, however, that it gets some vignetting at minimum focusing distance.