Originally posted by photoptimist But if you want to replicate what APS-C sees at 1:1, then you'll need to go to 1.5:1 on full frame.
Replication is futile, but in most circumstances, you can make up for the 1.5 factor by moving closer.
It's only the extreme magnification guys for whom, this would be an issue.
And if you're going extreme with bellows, extension tubes etc... you don't even need a macro lens for that.
As long as you respect that the field of view for 70 macro on FF is about the same as a 50 on APS-c.... which is why I went to the 100 macro, to replace the 70 when I went full frame. So I'd be working in a similar environment.
If I had access to the Tamron 90 without the wife taking it all the time, it would still be my only macro. I would have saved money buying his and hers Tamrons, as opposed to trying to find something a little different. The thing with macros is, if you own four, you can only put one of the camera at a time. I honestly don't think I suffer photographically regardless of choice. It's about other factors, weight , size, and which one you own and feel like using that day.
After the wife had her Tamron roll into a lake and I had my FA 50 macro take on water in a mishap in a canoe, WR all the way for me. Plus the DFA 100 is the most portable of the bunch. Looking at images, you're not going to see much difference.
DFA 100 macro
Sigma 70 macro