This lens was manufactured in 1980's by Tokina for Vivitar. It has its own multi-glass 1:1 adapter (I have the Canon FD mount). It is extremely sharp and has a "cult" following for it's soft creamy bokeh and is known among fans as the "Bokina".
This is very true. But the fact that the Minolta lens was only a little better and the Vivitar lens sold for much less made it a more popular choise and added to it's cult status. I unfortunately do not have a copy anymore because someone took it right out of my bag during a photography lab way back when.Because everyone is raving about this lens, I bought one too half a year ago. I compared it immediately with my Minolta MD Macro 100/4 and found that the Tokina's contrast is markedly lower than the Minolta's. The Tokina's sharpness was indeed excellent, but not better and its bokeh wide-open is indeed very nice; bokeh at smaller apertures around f/8 was equal between the two so as a macro lens there was no point in keeping the Tokina.
Especially the Tokina's lower contrast disappointed me and I resold it within a week.
Time to resurrect this thread, especially with the current discussions on legacy macro lenses.