Canon full-frame macro

What's the best macro lens available for full-frame Canon digtal SLR in the 40-70mm range that will go down to at least 1:1 repro ratio?

The only 1:1 full frame macro lenses in that range I can think of are: Canon EF 50mm macro + EF lifesize converter (I have this lens combo and hate it), Sigma 50mm f2.8 EX DG, and the Sigma 70m f2.8 EX DG.

I was using the 100mm Canon and the 1.4TC with/without the woodys wet lens yesterday on the MKII and got some nice images.

Stew

why 40-70 for 1:1? i find the working distane much too short - even with the 100 it's not easy to light a 1;1 subject

Kogia, the Sigma 50mm is a wonderfully sharp lens at all repro ratios.... and inexpensive too. But as Stevr says at very close focussing distances, getting your strobes in position to light the narrow gap between your port and get nice lighting is not easy. 1:2 is not so bad with a bit of practice but from there to 1:1 is just about impossible in my experience

Thanks to all who commented. Your advice is very much appreciated.