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View Full Version : Challenge: Need Help with Black Shadow on Images


Sheya Hans
March 12th, 2009, 04:16 PM
This may be a simple amateur question hope someone can help me. For some reason when using my Canon 50D with 17-85 f/4-5.6 IS USM Lens I get a black shadow at the right top and bottom edges of the images. It suddenly started yesterday – earlier shots came out fine – I tried many things to figure it out, various settings, shutter speeds and apertures but nothing seems to help.
I thought maybe there was dust or something with the sensor but I tried other lenses and those images seem to come out OK so it must be something with the lens.
Any help appreciated!

Following are some sample shots I have taken for the purpose of this post.

Problematic images taken with EF-S17-85 f/4-5.6 IS USM

http://farm4.static.flickr.com/3603/3348464734_eb2ed04e70_m.jpg
at 17mm focal length

http://farm4.static.flickr.com/3602/3348472464_f10b05de7e_m.jpg
at 85mm focal length

Following taken with EF70-300 f/4-5.6 IS USM Seem OK

http://farm4.static.flickr.com/3553/3348472324_2bffe43a52_m.jpg
at 70mm focal length

http://farm4.static.flickr.com/3429/3348472378_e44f18b9a4_m.jpg
at 300mm focal length

Bart_van_der_Wolf
March 12th, 2009, 05:47 PM
For some reason when using my Canon 50D with 17-85 f/4-5.6 IS USM Lens I get a black shadow at the right top and bottom edges of the images. It suddenly started yesterday – earlier shots came out fine – I tried many things to figure it out, various settings, shutter speeds and apertures but nothing seems to help.

Hi Sheya,

It looks like vignetting by either a lens hood that's a bit too long and/or narrow (or a petal shaped one that's not mounted correctly). The vignetting is also a bit decentered, so the lens may have an issue as well (did it fall?).

The vignetting is usually worst when you use a wide aperture (low aperture number), and usually at its least when you reach f/5.6 to f/8. All lenses have some vignetting (actually a combination of vignetting and light fall-off towards the corners).

Cheers,
Bart

Doug Kerr
March 12th, 2009, 06:13 PM
Hi, Sheya,

Hi Sheya,

The vignetting is also a bit decentered, so the lens may have an issue as well (did it fall?).

I too would be suspicious of the possibility that the lens had suffered some sort of impact that could have decentered an element group. In particular the apparent sudden onset of the phenomenon suggests some type of trauma-based problem.

Still, it would be good if you could try the lens on another body (perhaps at a store) to rule out anything in the body (a 20D or 40D would do fine).

Sheya Hans
March 12th, 2009, 06:16 PM
Thanks Bart
I didn’t have any lens hoods mounted at all. I do have a UV filter and I did try with and without the filter and the same thing happened.
This only started a couple of days ago until then it was fine. As far as I know the lens didn’t fall. I always remove the lens and put it back in my carry case after use .
If it is a lens problem does it mean I should send it back to canon? ( I just purchased it 4 weeks ago so I am covered by warranty) I was thinking of doing that by thought maybe there is just a simple solution.

Sheya Hans
March 12th, 2009, 06:20 PM
Hi, Sheya,

Still, it would be good if you could try the lens on another body (perhaps at a store) to rule out anything in the body (a 20D or 40D would do fine).


I will try that though i doubt thats the problem as i did try with other lenses on the body and they came out fine.