The GFX 50 doesn't have IBIS, but from experience, IBIS on the GFX100 is pretty much a miracle. When you get in to sensors 50mp and above, getting sharp images handheld, or even on a tripod, can be tricky. I've gotten decently consistent sharp images, handheld with the GFX100 down to 1/.5xSS, which really shouldn't be possible with a sensor of this pixel pitch. If canon is to arrive with an 83mp sensor next go-round, it will need a system even more accurate than the one on the GFX100. That combined with their new beachin' R glass will make a very competitive system, as long as the AF is accurate (BTW..good ibis helps with on sensor AF, so there's that). Oh, and the GFX100 IBIS on a tripod seems to be just fine, despite what you might have heard. I think this notion really applies more to video than stills.On the other hand, there's a review or two for the new Fuji GFX 50 or 100 showing that its IBIS seem much more effective hand held.