24-70 front focusing, am i doing somnething wrong?

[Ogilvy]

Hello, my new 24-70 appears to be front focusing on my 1d, this is most prevalent when I shoot at an angle, I first noticed it when i was trying to shoot a book spine in a bookcase, I noticed the spine was in focus but slightly soft compared to the spines preceeding it, I was at a 50-60 degree angle when I took it. I know the dof is shallow but is this normal? Since then I've noticed that there is a little front focus but I'm suspecting if it could be sloppy technique, I've put the camera on a tripod and i still notice the effect but other times maybe 70% of the time the focus is perfect. Can anybody please offer some advice, thanks in advance.

[rjgleason]

Hello, my new 24-70 appears to be front focusing on my 1d, this is most prevalent when I shoot at an angle, I first noticed it when i was trying to shoot a book spine in a bookcase, I noticed the spine was in focus but slightly soft compared to the spines preceeding it, I was at a 50-60 degree angle when I took it. I know the dof is shallow but is this normal? Since then I've noticed that there is a little front focus but I'm suspecting if it could be sloppy technique, I've put the camera on a tripod and i still notice the effect but other times maybe 70% of the time the focus is perfect. Can anybody please offer some advice, thanks in advance.
Can you provide some examples?

[dbevis]

As Bob said - post an example image ( and don't forget the exposure data).

At 70mm and f/2.8 and 2-5 feet from camera, the DOF will be only about an inch. This, coupled with the ambiguity of exactly where the focus was calculated from makes me think you could easily see what appears to be front (or back) focusing.


Hello, my new 24-70 appears to be front focusing on my 1d, this is most prevalent when I shoot at an angle, I first noticed it when i was trying to shoot a book spine in a bookcase, I noticed the spine was in focus but slightly soft compared to the spines preceeding it, I was at a 50-60 degree angle when I took it. I know the dof is shallow but is this normal? Since then I've noticed that there is a little front focus but I'm suspecting if it could be sloppy technique, I've put the camera on a tripod and i still notice the effect but other times maybe 70% of the time the focus is perfect. Can anybody please offer some advice, thanks in advance.

[Ogilvy]

Il try posting a sample image later, thanks so far.

[OlgaJ]

Those with the perfect 24-70s do not believe. :-)

Those who have gone thru 2 or 3 different 24-70s believe. :D

Olga

[dbevis]

Some of us swear by them, others swear at them. ;) I was lucky to get a good one the first try, but the lens hood ring fell off a few months ago (but fixed under warranty).



Those with the perfect 24-70s do not believe. :-)

Those who have gone thru 2 or 3 different 24-70s believe. :D

Olga

[Ogilvy]

Actually I just tested the lens on my d30 and the focus was spot-on, I also tested the 28-135 and 50mm and there is slight front focus if you look closely, with the 50 the max I would shoot it was at 2.8 and from a fair distance which gave me a more forgiving dof, the 28-135 I would shoot at 5.6 and above which masked the problem i guess, so my 1d will be going to the service center after my next wedding.

[Ogilvy]

Thanks for everyone's help btw. Much appreciated!

[DavidP]

Those who have gone thru 2 or 3 different 24-70s believe. :D


Unlike PearlRider, I didn't have to experience misfocusing 10D's to believe. Just expriencing a 1D (and some lenses) was enough. LOL.


I'm beginning to think that a smart person would just have his cameras and lenses drop-shipped from B&H to Irvine before having them delivered. :D

[Ogilvy]

I'm beginning to get that feeling too, the latest development is I have a loaner 1d from Canon while they're checking my camera, I'm observing the same behaviour with the 24-70, so at this point I'm thinking it's the lens. THEN, I use the lens on the d30 and every frame is spot-on, aarggh. Now I don't know what to believe. Did other members here have problems with their 1d?