This post isn't a crack on the camera at all, far from it as I am loving the thing more and more. It's just what to expect on full frame from your lenses. More of a crack on the 17-40L and even 16-35L by the sounds of things. $750 and $1500 lenses respectively.
17mm at F9 full picture.
100% crop somewhere around the center. Plenty sharp without any real sharpening yet. Next will be the upper right corner which tells the tale of full frame.
Pretty damn pathetic. Again, no fault of the camera obviously. But that is from an L series canon that is stopped down to F9. On a crop camera none of that would be in frame, just the full frame getting further out on the lens image. I haven't tested much yet, just noticing this on shots I took. I am doubting things will improve much past F9.
What is sad is it sounds like the $1500 16-35L II performs just as bad in the corners. So much for wide angle zoom options lol. I was considering trading in the 17-40L for that with some extra money, but not after the reading around I've done. Not sure what the plan is now in that department. It won't matter on storms/clouds/sky except for any foreground objects in the lower corners.
Here is another shot with some crops.
Past those red lines it gets pretty useless in a hurry. I'd say it can be sharpened near them a bit, just past the lines into the crappy area. 17mm again at F9. I looked at one shot at 27mm and it didn't look any better out there.
The resolution kind of blows my mind. This one towards the center and look how small of an area that is on the full version. I never live view manual focused anything either. Sharpen that a hair and the detail on a print would be pretty crazy. Consider the above isn't the focus point, as that was more on the close tree. It's just F9 DOF out there, but yeah at 17mm though.
Toast in the corners though. It doesn't have to be a huge chunk of the image though.
Big enough it is annoying however.
So, go full frame, better do some lens research as this is a sharp as hell 17-40L that goes to hell fast in the corners on full frame, even stopped down. It sounds like the $1500 16-35L will perform essentially the same in this department. Guess it is time to look at prime wide angles.
On a crop camera, the image is inside that crap area of the lens. Which gives me some hope it might allow me to sell this one lol. Just wondering more and more how much I'll want to use it on full frame. Sucks. Wonder what ultra wide options there are for full frames that are sharp in the corner. Probably the $2200 14mm lol. Seems like everything else will be 20mm or greater. Can't believe the 16-35L can't do any better in corners either.
Full frame....making your L glass look like a kit lens...well sort of. If only the area were a hair smaller it wouldn't be an issue to me. I tried to size that first one up to 16x24 to see what a print might look like and that upper right corner jumped out at me.
Noise levels aside, I'm realizing how much this argues for a 7D instead of a 5D lol. I have very little doubt I'd have better images with a 10-22 EF-s on a 7D than what I got from this 17-40L on a 5D II. Not yet sure what lens routes will cure this knowledge lol. At least my 100-400L is seeming more full frame friendly than I was thinking at first. Cheap 50mm 1.8 seems decent enough in corners from what I can tell on my limited shots with it on the 5D II.