> > Is F50/1.7 front element large enough to be reverse mounted on top of > Tamron SP90/2.8 ? SMC-M 28/2.8 works only when Tamron is set > > to f2.8, beyond that I get vignetting. Which lens is recommended for > reverse mounting ? > > It all depends on thread size. Just use step-up/step-down rings to make > them mate. >
mating is not a problem I have plenty of duct tape. > if you get vignetting, you need to add extension tubes between the camera > body and the prime lens. this will eliminate it. > > > > I see that it helps if I focus the Tamron as close as possible but not by > much. Is it good or bad the fact that Tamron has deeply > > recessed front element ? > > You should always focus as close as possible. yes, that seems to help but not as much as I would like. I think that front element on the 28/2.8 is just to small. I will get F50/1.7 in a few days and will try with that lens. > Again, extension tubes are a > big help. Tamron is already a 1:1 macro lens so it has its own extension tube which is very long. I noticed that there is not so much difference if I focus at infinity or as close as possible, there is a difference but not more that few f-stops before it starts to vignette. So If I add even more extension I don't think it will help much as I could end up with ridiculously long tube. Or adding extension is something different from what the Tamron is already doing, it is possible as rear element on Tamron is fixed and it is right at the end of the lens. > It shouldn't matter that the tamron has a recessed front element. > Strange that it does not make any difference. > Check out John Shaw's "Closeups in Nature" A great book with all kinds of > techniques for macro. That is the only photography book I have. :) I guess I should take a look if there is anything that could help me, I did not think of that. :)
