Dissatisfied with performance of 24-70L (v.1)

Hi,

I'm trying to diagnose some issues on my 24-70 f/4L (first version). I don't know if my lens is damaged, or I'm just spoiled by the superb performance of my 70-200 f/4L.

I got the lens used from B&H about 18 months ago. I don't remember it acting up until recently. In the past six months or so, the left side of the image (horizontal orientation) just gives unacceptable results.
[edit] It has given the same results in the past, just not on every shot - it's very inconsistent)

It doesn't seem to be EVERY time, but maybe 2/3 of the time.

Doesn't seem to be missed focus? The 70-200 seems to focus way better, but the 24-70 doesn't miss TOO bad. I would expect a 2.8 lens to have better focus performance than an f/4 lens anyway, though maybe this isn't as applicable on the 5D3.

Example 1. I used one of the top focus points, to focus on the face & eyes. Very little focus-n-recompose, maybe a little bit. Full image, resized.

IMAGE LINK: http://www.flickr.com …nathancarter/12​389085894/

IMAGE LINK: http://www.flickr.com …nathancarter/12​388834713/

IMAGE LINK: http://www.flickr.com …nathancarter/12​388689315/

IMAGE LINK: http://www.flickr.com …/nathancarter/9​887586495/

The EXIF on the top photo shows SS at 1/160, f/5.0 and ISO 100 with a 5D3 body. Reasonable settings for that shot, and I would have expected the image to be sharper than what you posted.

With a used lens, you never know what you're going to get, and I assume the images were sharper when you first got the lens 18 months ago? In any case, I would suggest sending it to Canon for a clean and calibrate service. I did that with my 24-70 f/2.8 V.1 and it now produces stunning images with my 5D3.

Thanks for the comments. Those camera settings killed all ambient; the light was two Elinchrom strobes, so it's definitely not a motion-blur issue.

The images out of the 70-200 look great, from corner to corner. Even shots from later in the night, where I had to crank up the ISO to 12800 and use ambient, looked better than the posed/strobed shots.

I went back and carefully inspected some images from 14 months ago, and SOME of them exhibit the same characteristics. It's not consistent, though. Some of them are pretty sharp all over, some of them are reasonably sharp on one side and "mushy" on the left edge (or bottom edge, in portrait).

Maybe one of the elements is loose or something, I dunno. I'll see if I can send it back for an inspection & calibration. Got a wedding next weekend, it's gonna have to wait until after that. :/

Any alternatives to Canon? I've used them once in the past for a different and was not 100% satisfied.

Nathan,, I'm definitely seeing a problem with the left hand side of the image. I'm thinking some kind of misalignment of element(s).

Could be a repair job for Canon.

Nathan,
You have kinky friends.

have you tried micro-adjust? it might fix it. If not then for sure send it in for repair.

i saw an article on Lensrentals.com about issue on aging 24-70/2.8L. Some of their 24-70's has broken collar which caused the screw to loose inside the barrel and bring an incorrect focus. You might read the full article here.

Not all aging 24-70/2.8 has this issue but you still have to be aware.

nathancarter wrote in post #16673891
Maybe one of the elements is loose or something, I dunno. I'll see if I can send it back for an inspection & calibration. Got a wedding next weekend, it's gonna have to wait until after that. :/

Any alternatives to Canon? I've used them once in the past for a different and was not 100% satisfied.

I've only used Canon's services and had good experiences. However, if you are not satisfied with their service, if you let them know they will try to make it right. Alternatively I'm sure you can find independent lens repair shops on the internet.

That looks messed up.

My 24-70 is finicky in that I can't expect it to just nail focus on the first half-press then click. I have to half press, half press, half press until it actually stops turning and settles down. It's as if it's not sure where it really ought to be. And this is no matter what camera I use - 1D3, 1DII, etc.

But this isn't a focus issue. Look at the left side of the last image, it's like an element out of alignment.

That first image as a whole doesn't really look f/5 crisp though, and that's what I can end up with if I don't dance. I'm not saying it's fine. I'm just saying.

I can't speak to the edge but it does look a bit like my Sigma 12-24 edges. I've always chalked it up to a poor design on Sigma's part but maybe it's a dud too. I don't use it much.

As others have said, it looks like an alignment issue to me...

definite alignment issue, im not sure about the focus, but i think the first one, her nipple popped out

Thanks all, for the confirmation that I'm not just imagining things.

Danisnug, thanks for the link.

cdifoto wrote in post #16677429
That first image as a whole doesn't really look f/5 crisp though, and that's what I can end up with if I don't dance. I'm not saying it's fine. I'm just saying.

Yeah, I agree. Though I rarely pixel-peep, I would expect much better than this out of any L lens. The weird stuff on the left edge just exacerbates the issue - if it was the same across the whole image, I could deal with it.

skilsaw wrote in post #16674858
Nathan,
You have kinky friends.

Quite.

burb1972 wrote in post #16678227
definite alignment issue, im not sure about the focus, but i think the first one, her nipple popped out

Pasties under the corset, so nothing is unintentionally revealed.
But, yeah, the corset could have been laced on a little higher, especially for that pose.