Sudden vignetting visible - EF 100-400mm f/4.5-5.6L IS USM

[XANDERIX]

hi there, I have bought a - second hand - Canon lens EF 100-400mm f/4.5-5.6L IS USM from Japan from my EOS 70D. I use it for nature and airplane photography. I did not have any challenge with it and it worked well for 3 months or so. Then suddenly I discovered extreme vignetting when editing pictures. I did some comparison with differen focal lengths and aperture, see the image below. I am not using lens caps or anything.

Any suggestions on whether this can still be solved? The lens didn't drop or so, at least not with me, but I still need to discuss with the family...

[rs-eos · Accepted solution]

But isn't that then an issue with the website in how they are processing things? These RAW files you shared have absolutely minimal amount of vignetting in them.  So not sure what the issue is.

[rs-eos]

Things are definitely darker along the right side.  If you don't have any screw-on filters, or other attachements, then the lens may indeed have an issue.  Though purchasing a lens used and not within the US, it may be very difficult to have Canon USA service it.

[kvbarkley]

What are you using to edit?

Do you have lens corrections turned on?

Does your software recognise the correct lens?

Ken Rockwell showed the falloff he measured:

https://kenrockwell.com/canon/lenses/100-400mm.htm

[XANDERIX]

I am using the Canon software and already use the correction for the correct lens. As said, vignetting was hardly visible up to some two weeks ago. Can vignetting appear after the lens suffered a shock?

[kvbarkley]

I would think so. Can you see it through the viewfinder, or only when editing?

[XANDERIX]

no, not through the viewfinder, only when editing the pictures

[MikeSowsun]

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@XANDERIX wrote:

no, not through the viewfinder, only when editing the pictures

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I would say your lens is fine, but your editing software that has a problem. 

[kvbarkley]

Does it show up in JPEGS?

[ebiggs1]

U/l an unedited raw file to a Dropbox or Google Drive and let some if us check out the original file. If it still shows the issue then you probably do have a faulty lens.

Post the link to the file here on the forum.

[XANDERIX]

https://www.dropbox.com/scl/fi/oala1930dl5a92ty6yfrv/IMG_6026.JPG?rlkey=1hz0n15pfmsm2fmdzyvfvqk0s&dl...

look, i just took this picture in heavy dust environment, it is RAW format and no cropping/editing: