Originally posted by HoutHans That's a great lens, and indeed the fringing can be quite annoying on the Pentx Macro. Nice and well-lit images with an amazing amount of detail.
This lens apparently made its appearance in lots of different mounts and brands. I have what I think may be the same lens as a Tamron SP AF 90mm f 2.5 macro 1:2 (AF Minolta/Sony A mount), 8-blade shutter. I also have something similar as a MF Tokina AT-X 90mm f 2.5 macro 1:2 (Pentax K mount), 8-.blade shutter, nicknamed the Bokina because of its smooth bokeh. I do not have any precise knowledge of the common background of these lenses, but think I have read somewhere of some kind of common parentage. Tracing this sort of thing is problematical because of cross-licensing, third-party production agreements, company closures, design upgrades, and the like.