Originally posted by Kunzite Indeed, this site found a vignetting level similar with that of the Canon 600mm f/4 IS II; and they thought that means it's not a full frame lens. Now they're measuring resolution and other stuff, and I really hope they'll follow Falk's advice; otherwise... well, I don't want to think about that.
Is that all?
Well, yes, other than the fact that it's called out as an APS-C (which I don't really trust either). But yup, 'that's all'.
When that 1.3 or whatever number came out I looked at other lenses, because I thought 1.3 wasn't that bad... and the worst I found was ~0.6 or 0.7. Don't know where you're getting a Canon 600mm showing 1.3 EV of vignetting... but even still, I'm sure the Canon's doing super-awesome at f/5.6.
Having to stop down to f/8 on a $7k lens sounds a bit ridiculous to me, but everything about this lens seems ridiculous to me.