Are there any resolution / quality tests / comparisons available on the Pentax MF lenses?
There aren't many that I'm aware of which is not too surprising since Pentax MF had long been given up as dead. Here's one concerning the 645 35mm FA:
http://www.16-9.net/lens_tests/pentax645_fa35mm.htmlThe 35mm FA is a difficult lens to find as many have been adapted for use on DSLRs.
The same site makes the following statement about using Pentax 645 lenses on a Canon body using a Zörk adapter (of course he was selling the lenses, so a grain of salt is recommended).
“This is simply the best way to obtain maximum shift movements on a Canon digital body. The Zörk Panoramic Shift Adaptor permits movements of up to 22mm, and is the only system designed for DSLRs to accommodate parallax-free stitching. The lenses I'm selling with it have been chery-picked for ultimate performance: the Pentax FA35 is just the greatest medium format retrofocus wide angle ever. The SMC-A 55mm f2.8 is a cracking manual focus Pentax 645 lens that outperforms the Hasselblad 50mm CF. And the butter smooth manual focus 150mm f3.5 is even better at distance than the Hasselblad, Mamiya and Pentax Macro 120mm lenses. In my opinion (and that of Zörk in Germany), the Pentax 645 range is the best array of MF lenses ever, with a beautiful, Zeiss-like drawing style and bottomless resolution. Until a digital Pentax 645 option arrives, this remains the best way to unlock that potential in the digital realm"
The site has an interesting, if unrelated, discussion of adapting a number of lenses to Canon bodies:
http://www.16-9.net/lens_tests/compatible.htmlFWIW, my personal experience with about 20 Pentax MF lenses is that there are no dogs and some are outstanding. The 645 35mm and 120 macro are superb as are the 67 300mm ED, 400mm ED and the 55-100mm zoom. Of the lenses I’ve used, the only one with serious shortcomings is the 67 35mm fisheye.