VR/IS/OS/VC doesn't help at 1:1. Even Nikon says its use at that kind of magnification is moot. I used the Sigma 105 for awhile. Good lens. I like the Sigma 150 much better though for the working distance and, this is a big one, better handling of CA and colors.
Thom Hogan:
"The exact words in the Nikon manual say "As the reproduction ratio increases from 1/30x [sic], the effects of vibration reduction gradually decrease." In other literature, Nikon has flat out said to turn off VR for macro use. What's the real answer? The manual is correct, basically. The closer you focus, the less VR has an impact on the final image. At 1:1 (the closest focus distance), it may not impart any benefit (it didn't seem to in the testing conditions I could create). So do you turn VR off when working in macro? If you're pressed up towards the limits of focus, I'd say yes--you're wasting battery life and potentially making it more difficult to hit a focus point. But if you're focused out beyond two or three feet (~.7m+), it probably makes sense to leave it on, as you'll get some benefit (though not the four stops Nikon claims for the system unless you're focusing far further out into the scene)."
On the 1.6x magnification of the 7D sensor, the Siggy 105 should be good. If the OP likes it well enough, the Canon makes a 180 macro don't they?
