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advice please: faulty camera?

M

masteroflondon

macrumors 6502
Original poster
Sep 17, 2007
261
295
London, UK
I just got a new EFS10-22mm f/3.5-4.5USM lens for my birthday. Bowled over by it, such an incredible wide angle!:D

Then I noticed the left side of images tends to be out of focus. So I took some test photos linked below. WARNING: Large images, 38MB each. I hope that's reasonable, I thought all the detail was necessary for anyone to help with this.

My findings are that if I focus on the centre, the right side is less focused and the left side of image has downright poor focus.:(

I also tried same tests with a 50mm EF 1:1.8 MKII and my EFS 60mm macro 1:2.8USM. The longer the focal length, the better and more consistent the overall focus. The 60 is actually OK, I think and the 70mm end of my 70-300 is fine too.

So my initial fear was my nice new lens is faulty. But these tests seem to show the wider the angle, the more some flaw in the camera shows up.:confused:

I only posted the 10mm and 50mm samples, as they are the only ones with pronounced issues. I also posted a Manually focussed version of each, showing when I focus myself, on the same spot the AF was doing, I get better results from edge to edge. Not sure how that works either.

All images are focused on the 12 rating certificate of Friends season 6.

My camera is an EOS 300D, so it's old. I want to get a 7D! Is the camera simply not up to the lens? Faulty?

Thanks for your time and advice.

10mm manual focus
http://dl.dropbox.com/u/247158/10mm%20lens%20tests/10mm%20MF%20test.tiff

10mm auto focus
http://dl.dropbox.com/u/247158/10mm lens tests/10mm AF test.tiff

50mm manual focus
http://dl.dropbox.com/u/247158/10mm lens tests/50mm MF test.tiff

50mm auto focus
http://dl.dropbox.com/u/247158/10mm lens tests/50mm AF test.tiff
 
One more thing, on the 50mm shots, focus (no pun intended) on the 'M1T' number under the 12 rating certificate. I think it's where the focus issue is best observed.

Thanks again!
 
What is your F-stop set to for all your examples?

From my perspective you possibly have 2 issues, that I have experienced myself. (A) You have a focus issue, with the Camera itself, within the focusing algorithm, or (B) you could possibly have a shifted element in the 50/1.8. To be honest, I did not notice anything wrong with your 10mm examples, except for what appears to be a shallow DOF. If you don't have enough DOF, then the edges will have an Out Of Focus (OOF) appearance. Since you have shared them as QT files, Exif Info is not accessible.

Hope this helps.

James
 
As mentioned above, we need to know what f/stop you sot this at. All lenses have a "sweet spot" where they perform best in edge to edge viewing. My new Sigma is very sharp at f/8 - f/16 and gets a bit soft at the edges wide open. Another thing I noticed is that your camera isn't parallel to your test surface. Turn on your grid view and make sure everything is perfect, then shoot this with a remote release to eliminate all camera movement. I assume you are using a tripod.

Dale

Edit: Shot at f/3.5
 
Last edited:
Thanks for the responses. I'm not at home right now, so I'll have to post exit tomorrow. Didn't realise I'd stripped it out, though jackerin seems to have found them?

I tried very hard to make it all parallel, don't think i have grid lines on the camera, I'll check.

James, i understand depth of field would be an issue if the camera/subject were not parallel, are you saying the difference in distance from the lens to what's directly in front versus lens to what's at the edges would also count as DOF? It never occured to me, though i see it is a greater distance. I guess i thought it was just a matter of planes, not measured distance.

Are you guys saying you don't see the focus difference, or that what you see is what you'd expect? Look at the auto focussed examples, the extreme left dvd's are a lot different than the centre Friends set.

I took street photos this morning and it was those that first turned up this issue and prompted me to make the test with, i hope, a suitable subject to make the issue clear. Maybe the subject was poor, being to close up?

Also, the poor focus always seems on the left of the image, never the right.

And if DOF is the cause, why does manual focus fix it?

I'll post the exif and f stop tomorrow,
Thanks again for all your help.
 
masteroflondon said:
Thanks for the responses. I'm not at home right now, so I'll have to post exit tomorrow. Didn't realise I'd stripped it out, though jackerin seems to have found them?

I tried very hard to make it all parallel, don't think i have grid lines on the camera, I'll check.

James, i understand depth of field would be an issue if the camera/subject were not parallel, are you saying the difference in distance from the lens to what's directly in front versus lens to what's at the edges would also count as DOF? It never occured to me, though i see it is a greater distance. I guess i thought it was just a matter of planes, not measured distance.

Are you guys saying you don't see the focus difference, or that what you see is what you'd expect? Look at the auto focussed examples, the extreme left dvd's are a lot different than the centre Friends set.

I took street photos this morning and it was those that first turned up this issue and prompted me to make the test with, i hope, a suitable subject to make the issue clear. Maybe the subject was poor, being to close up?

Also, the poor focus always seems on the left of the image, never the right.

And if DOF is the cause, why does manual focus fix it?

I'll post the exif and f stop tomorrow,
Thanks again for all your help.
Click to expand...

You don't need to bother posting the EXIF data, Get Info displays all of it from a download of the file. I would tend to point the finger of guilt at your camera. The Canon 300D was introduced in 2003 with a 3.5MP sensor. No matter how good a lens you put on it, it could still have issues with autofocus. The motor that drives that function is in the lens, but it takes it's orders from the camera. That could be why manual focus seems to curb the problem.

If you can, take it to a camera shop and bring your own memory card and lenses. Ask to take a few test shots with your stuff on a newer camera body. You might even be able to rent the body for a day or so. The link below is for an operation that does this.

Lens Rentals

The 50D is the least expensive to rent. $63 for 4 days.

Dale
 
For sure it looks like the AF is a little miscalibrated, the MF results are clearly sharper all over than the AF. However, lots of fine detail like these frames does not make for a good AF target, and thus the AF system could just be misfocusing due to the subject material. I'd suggest more testing with different AF targets before concluding on that.

As for the left-right imbalance, the 10-22 definitely seems softer on the left vs. the right. It could be a poorly centered element, however, it also seems to exist on the 50mm shot to an extent, and therefore it's also possible the uneven softness is due to a warped body or lens mount.

It might be worth re-shooting the test, being extra careful to get the bookshelf/wall/target exactly parallel to the sensor plane. That would help eliminate DoF type issues, and allow you to check for uneven sharpness again.

Ruahrc
 
I just wanted to come back and say thanks for the help. It seems there's fairly uniform agreement it should be the 300D, not the lens at fault. I went back and did more tests and very clearly the 50mm is showing exactly the same fault in exactly the same place, just to a lesser extent, than the 10mm. My 60mm looks as though it's probably doing it also, though it's hard to be sure. I dug out my old 18-55 kit lens, and that does it too, more at 18 than at 55. So the shorter the focal length, the worse it is. No one seems quite able to explain it, but I consider the 50mm issue being identical to the 10mm to be conclusive proof, it's the camera.

That's another excuse to get the 7D!

So, many thanks for the help and support.
 
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