70-200 f/2.8L blurry at 200mm + low aperture

[izzi]

I have been using this lens with my 6D for years (admittedly not regularly - only when I travel), but have recently noticed that things get blurry (moreso toward the outer edges of the image) at 200mm with lower apertures. I can already see the blur through the viewfinder. At higher apertures, photos actually come out less blurry than what I see through the viewfinder. Here are some test images (200m, one-shot AF on the text - I've also tried MF with same results).

f/2.8:

f/8.0 - not as bad:

I'm assuming there's some sort of lens damage - perhaps moisture? Any tips to try out in the field? I won't have access to camera repair for a few months. Thanks in advance!

[Peter]

What if you use live view as focus method? Take a picture of something without depth. A brick wall for example.

[ebiggs1]

"Here are some test images..."

Neither of the sample shots prove anything. Keep in mind as your FL increases all imperfections increase. It is normal for 70mm to look better than 200mm. Also when you are testing your lens you must keep everything on the same plane and square to the camera/lens combo. The suggestion of a brick wall or other flat surface is good but not by itself. You still must keep the camera/lens perfectly 90 degrees form the subject wall. Otherwise the test is invalid.

Your sample shots suggest you may have been slightly to the left of the subject. And, if that was the case DOF would explain the issue. DOF, at 200mm and f2.8 and at that close of distance to subject, will be very shallow.

[izzi]

Thank you both for your suggestions! Here are two more sample photos - 90 degrees to flat surface, taken with live view. I should also emphasize that this is a recent issue after years of sharper photos under same conditions (200mm in low light) with this lens + body, and that the blur is highly noticeable through the viewfinder.

 f/2.8 and f/8 again:

[rs-eos]

As Peter mentioned earlier, it would be much better to provide images of something with no depth such as a brick wall or any wall with enough detail on it).

In the new images, even at f/8, the item in the background (left) with the recyling logo is in an out-of-focus area.

[ebiggs1]

Not wanting to beat a dead horse but you are not perpendicular to the box. You must be in order to determine anything.

"...taken with live view."

That has nothing to do with how sharp your lens is. Perhaps you have a faulty lens, it happens even to the best. You have two ways to go, send it to Canon and ask for a C&C or you can test it properly to see if it truly needs to go to Canon. You will need a tripod and a perfectly placed camera/lens to subject set up. I would also suggest you do this in good lighting conditions to avoid any focus misses.

[Waddizzle]

“ That has nothing to do with how sharp your lens is. Perhaps you have a faulty lens, it happens even to the best. You have two ways to go, send it to Canon and ask for a C&C or you can test it properly to see if it truly needs to go to Canon. “

Testing your gear is just as much a test of the photographer as it is the gear, if not more so.

[ebiggs1]

"As Peter mentioned earlier, it would be much better to provide images of something with no depth such as a brick wall ..."

That isn't good enough. The camera/lens has to be in perfect alignment to the wall or the test is useless. Also set on a sturdy tripod. The SS (1/160) in the test photo was also a bit slow if it was hand held.

[FMTrindade]

Hello.

Sorry for reopening this but I am under the impression that either we are getting too technical or something is way out of what was indented here...

Izzy: Your lens sucks at 200mm f/2.8 Period!
Unfortunately, there is no need for a 100% perpendicular test to assess that and if everybody else is demanding that, they are just blind. Or unexperienced users.

I have the same issue with my EF 70-200 IS L USM.
It sucks at 2.8 it's fair at f/3.2 better at f/3.5, sharp at f/4.

The thing is so bad that at 200mm f/2.8 I could see a ghost and there was a pixel shifting.

I have opened the lens, went trough all elements, cleaned them up, remounted the lens trying to align everything with the help of precision measure rulers as best as I can, and the result is:
- more sharp;
- no ghost at 2.8
but still soft as hell at 2.8
3.2 is now more than acceptable at 200mm

A7 70, 100, 135 all are ok.
It is just at 200 f/2.8 that this happens and I still can't figure out why!!!
I mean, obviously the circle of confusion is way larger than the camera pixels but heck, if it happens, then I have to move the camera backwards or forward... looks like at f/2.8 the focus plane is NOT on the sensor plane.

[ebiggs1]

Us "inexperienced users" can easily see you are about 8 months late to the party which by this time is most assuredly over.