EF 24-70/2.8L misfocuses @ 24-35 mm

[ahavriluk]

I have got EF 24-70/2.8L lens quite ago tested it for back/front focus and it seemed to be OK at that time. The camera has no back/front focus problem. It was recalibrated by Canon before.
The problem started showing up in real life shooting situations. The lens was missfocusing mostly at 24-35 mm at 2.8 at distances 10-15 feet and more. If it was set above 35mm up to 70 mm the focus was right on spot. It is not a back/front focusing issue, since if I refocus and shoot a few times in a raw the lens might get the right focus. The very high contrast subjects make it focus better then real life subjects like people. So, the test shots didn't show the problem.

Seems to be that it happens quite often with this lens.
Is it the limitation of autofocus accuracy for such conditions?
Did anybody get it fixed by Canon by sending it for recalibration?
Can anybody comment on that issue?

It drives me nuts since I am getting important shots for clients misfocused and I can't see the issue until it is enlarged on computer monitor. The camera is Digital Rebel/300D. I have tested it with 5D and it seems to have the same issue there as well.

Alex.

 

[dragos]

bring your cam body and the lens to canon again..

 

[canonws]

Dun seem to have that problem. The len is working fine with me...

 

[sk.images]

Mine is razor sharp at all focal lengths - no problems here.

 

[shinken]

Did you zoom in, focus, then zoom out to recompose? That could cause the inaccuracy for some lenses, including this one.

 

[ahavriluk]

Did you zoom in, focus, then zoom out to recompose? That could cause the inaccuracy for some lenses, including this one.

I tried that method too. I don't use it because of that reason.

 

[gryphon]

I had e SAME problem.... at wide range, sometimes will misfocus. I did extensive tests before that, did focusing test & newspaper test for sharpness at f2.8, f4, f5.6 all tests are good.
But when using to shoot, I got quite a few pictures at wide range focusing is out. All my longer range are excellent.

Passed both my camera & lens to canon. They had to change the motor, cost me nearly $200 :bheart:
Now its working properly.

 

[madmacs]

only at f/2.8? if you are sure its not due to shallow dof, then do another tripod mounted lens test. if still back focuses then send it in to canon. i had to send mine in to canon twice before i got it sharp at f/2.8.

 

[gryphon]

only at f/2.8? if you are sure its not due to shallow dof, then do another tripod mounted lens test. if still back focuses then send it in to canon. i had to send mine in to canon twice before i got it sharp at f/2.8.

mine was at all apertures (most of my shots at f4 - f6.3). Confirm not due to shallow dof
ahavriluk mention that for him its at f2.8

 

[EUGSEOW]

My 16-35mm f/2.8L has similiar problem.

I think there is nothing wrong with our lens, depending on what you are focusing on, most likely, your object is too small (at wide focal length) for the AF sensors to 'measure' already. These AF limitations are mentioned in all EOS body instruction manual.

Both my 1D and 5D behaved the same too.

 

[ahavriluk]

My 16-35mm f/2.8L has similiar problem.

I think there is nothing wrong with our lens, depending on what you are focusing on, most likely, your object is too small (at wide focal length) for the AF sensors to 'measure' already. These AF limitations are mentioned in all EOS body instruction manual.

Both my 1D and 5D behaved the same too.

It might. But look at this picture. All background is in focus but not subject.

The subject is large enough for AF to catch it. It is not acceptable for me. I can't screw up shots like that.

 

[madmacs]

i think you should send it in to canon. my 24-70 gave me the same issues you have before i sent it in.

 

[ahavriluk]

i think you should send it in to canon. my 24-70 gave me the same issues you have before i sent it in.

I think I have to. It is very inconsistant and I am afraid they might not find any issues with the lens.

 

[madmacs]

I think I have to. It is very inconsistant and I am afraid they might not find any issues with the lens.

that is possible. so make sure you send in your dslr with the lens so that they can confirm. i also sent in my 70-200 f/4 for calibration. they told him it was spot on. so i brought in my 10d for them to test and they confirmed that my 10d + 70-200 f/4 combo was backfocusing. so in my case, the real problem is most likely the 10d.

 

[EUGSEOW]

I think so too. Did you check where are the focusing points?
Which dSLR is this?

It might. But look at this picture. All background is in focus but not subject.

The subject is large enough for AF to catch it. It is not acceptable for me. I can't screw up shots like that.

 

[madmacs]

I think so too. Did you check where are the focusing points?
Which dSLR is this?

Digital Rebel/300D. he mentioned in the 1st post.

 

[EUGSEOW]

Oh yeah, pardon me, I missed. ;p

Digital Rebel/300D. he mentioned in the 1st post.

 

[ahavriluk]

I have decided to wait for my 30D and then see how it performs with a new camera.

 

[Moonstone]

Just send in your lens to Canon for checking; I did encounter this type of problem with one of my 3rd party lens, it's very irritating because you never knows when it miss-focus again - almost drive me crazy.