16-35L II - How bad should be corners be?

I saw something weird in the corner of a 16mm shot with my lens. Detail seemed to be really kind of funny smeared. So I ran a quick check.

I know - Fast and UWA probably should never expect wonderful corners wide open, but look at how these corners look. Kind of strange.

So here we go into the images. To start, Here is the entire image and then a center crop for reference at f/2.8

HOSTED PHOTO
please log in to view hosted photos in full size.

HOSTED PHOTO
please log in to view hosted photos in full size.

Next, Corners at f/2.8 and then for contrast at f/8. Look at how fast the corner falls apart at f/2.8. I wonder if anyone else with this lens can comment on how theirs looks.

Two other notes - all 4 corners are about the same, and the lens gets better at every stop from f/2.8 to f/11.....but the corners are noticeably like this to f/5.6 or so.

HOSTED PHOTO
please log in to view hosted photos in full size.

HOSTED PHOTO
please log in to view hosted photos in full size.

And here is f/11, I guess I'd say the corners are pretty much fixed by this aperture.

HOSTED PHOTO
please log in to view hosted photos in full size.

Looks about right. I own that lens.

This is one of the reasons why I wish that I had a good 20MM prime instead for landscape work.

I just expect this problem with landscapes, then crop.

That said, I will never sell the lens; I do use it and enjoy it.

i've owned the 16-35L II four about four years. i shoot it alot around f3.2 @ f3.5 but my subject is never in the corners . and i really love that lens!

ed rader

ed rader wrote in post #13404965
i've owned the 16-35L II four about four years. i shoot it alot around f3.2 @ f3.5 but my subject is never in the corners . and i really love that lens!

ed rader

Heh....I owned this lens for over a year and I only just noticed the corners doing this.

Of course, usually at f/2.8 there will be nothing in the exteme corners that is in focus anyway. And that's how things were for me for over a year. Then I took one shot with something in a corner and I could see this smearing.

So all I was wondering was if this was normal. I've never had a lens that showed such an abrupt change at the extreme corner before.

The 17-40 suffers from corner softness on a FF body also. Visible on an APS-C sensor but not as noticeable. Kinda the reason that some serious landscape guys use the Canon\Nikon adapter with the highly regarded Nikkor 14-24.

Ah, I forgot about that one -- I looked at that before getting the Canon -- It was on the list along with the primes.

Great lens. Perfectly normal results. Like others have said, if you're shooting at 2.8 for effect or low light, your subject isn't in the corner and you will unlikely care about the extreme corners.

To do any better requires a compromise - manual focus: the already mentioned 14-24 or a Samyang 14mm with software correction and a crop (cheapest option), or manual focus and loss of aperture: 17mm TS-E.

Oh darn. I was really looking into getting this piece.

tomcat7886 wrote in post #13405513
Oh darn. I was really looking into getting this piece.

I certainly wouldn't let this information deter you from your plan.

If you are shooting at 2.8, you are likely focusing on a specific subject and hope to blur everything else. The blurred corners will only help your goals.

If you are shooting above 5.6, you will get nice sharpness across the frame. Like any landscape shot.

Here's a 16mm sample at f8.

How close were you to that wall. The corners will be significantly further from the camera than the center of the wall. Shoot from further away. I am not saying you will get sharp corners but they might be better than those samples.

Looks about right.

The corners on full-frame are pathetic. OK when stopped down to f/8-f/10, but no competitor to the Nikon 14-24 or 16-35 on full-frame, or Sigma 8-16 or Canon 10-22 on crop.

The centre, on the other hand, is incredibly sharp.

bohdank wrote in post #13405667
How close were you to that wall. The corners will be significantly further from the camera than the center of the wall. Shoot from further away. I am not saying you will get sharp corners but they might be better than those samples.

Shouldn't make a distance - the plane of sharp focus should be a plane perpendicular to the axis of the lens, not a sphere a certain radius from the iris.

those are pretty representative of a good copy. I have tried 3. one was bad the other two good ones perform similar to yours.
Only other thing, the lens has a focus field curvature, with corners performing a little better close rather than far.