Photoclubalpha

I read in a old paper magazine "FOTO" here in sweden. They testet sony 100mm macro vs Sigmas 105mm macro.

accordning to their test the minolta/sony one was mediocre and not sharp until stopped down quite alot , but the sigma was sharp at full opening.
They also gives critque to online MTF testing, (SFR testing) which usually meassures the hole system, lens + body + raw converter, but their test meassures the true performance of a lens, regardless of body used.

Are there any substance to these claims ? And is sigmas macro actually better than minoltas? (sonys)

Not sure about the results they've found there. I've the Sigma, and it is not sharp until f4 minimum. F8 is the sweet spot for this lens. The Tamron 90mm macro beats the Sigma hands down wide open.

I've never used the Sony/KM, but hear only good things about it (except for cost!)

I've got the Sony 100 f2.8, and previously owned the Minolta 100 f2.8 (the earlier version, not the one that Sony now manufacture). I found both lenses produce very good image quality wide open, and by the time you reached f4 they out resolved either film or 12mp digital. I can only assume that the test you refer to had a really bad example.

Philip

I also use the 100M28 and have had no complaints with the resolution this lens provides, even wide open. Other than available light, I've used the HV-RLAM with it as well.

I trust FOTO tests as they use the former Hasselblad/Zeiss test facility to examine their lenses. They must have had a poor sample - very rare with this lens - and it's surprising they did not check further examples. The 100mm macro is optimised for best performance at 1:10 repro, not as close as you would think, so tested at 1:1 or 1:2 it is possible the Sigma might be better wide open. Minolta's logic was simple - people will use the lens wide open on portraits or landscapes, so make it dual purpose. Most people stop down to f11 or so for macro shots, at which both will be excellent.

David