I'm a bit complicated since I bought the EOS 6d and now I have to decide what macro to buy for Oral Clinic photography (I'm a dentist).
Formerly I had a 500d with a macro of 60 mm, and I was handling with very small openings (f stop) since I need great depth of field (f / 22, f / 28, f / 32). It turns out that now I wanted to buy the "Sigma 105mm 2.8 Ex Os Macro" lens mainly for its value compared to "Canon EF 100mm f / 2.8L IS USM Macro", but I realized that the minimum aperture of the Sigma diaphragm is f / 22 (Canon's is f / 32).
I'm afraid that the Sigma will not give me the depth of field I want (the front teeth and the back ones will be focused) .. But the truth is that I do not have macro frame experience with Full Frame and maybe that f / 22 sigma is not very different from the f / 32 of the canon, or perhaps it can be very different ...
I would like to know your opinion, because if there were not so many differences I would prefer to save money and buy the sigma