What's your take on the performance? The way I would use an 85 on ff, I'd be shooting it close to wide open for natural light solo portraits, and in most other circumstances, I'd be stopping down into sharp territory. So, again, my takeaway is that dof control is the primary gain. Otherwise, m43 is just fine. But do you crave the "punchiness"?I shot my chart today and confirmed what Lenstip.com's test showed. The sony performs pretty poorly away from the center. Doesn't get super sharp in the center until F5.6. It is pretty comparable to the 45 1.8 Oly lens--maybe a hair sharper in the center wide open, but the fall off is toward the edge is quick and about 1/3 of the frame from center it's not great at all. Also, there is a little color fringing, but not very noticeable. In practice, shooting my kid and dog running around the lens looks sharp enough, the FF image is a bit cleaner and the lens is "punchier" so it looks great at normal viewing resolution. I also compared it to the Oly 12-40 @40mm&2.8 and the OLY is superior. Against the 12-100 Oly @44mm&F4 they were similar across the frame. The 75mm1.8 is sharper but has some fringing.
If anyone is interested in any particular comparison let me know.