need help from experienced 24-70mm users

Was earlier this year-February I think. And no "Calibration Deterioration".

dipps wrote in post #8810941
btw, how long ago was that? have you seen any "calibration deterioration" since then?

By any chance was the OP in AI Servo focus mode?

My 24-70 will misfocus from time to time when I'm in this focus mode but shooting static subjects. For some reason, it wants to hunt and will miss from time to time.

Tracks moving subjects fine just burps occassionaly on static subjects.

Any time you buy a new lens and it has a warranty, you should feel free to use that warranty very liberally because it's the only thing justifying the "new" premium. I had a soft copy of the lens that went back to canon 3 or 4 times (I lost count) before it was finally sharp.

The photos are out of focus (looks like focused on the foreground) except for the one with the woman and two children. That one is typically what the 24-70 should deliver. Your lens is fine.

FlyingPhotog wrote in post #8811099
By any chance was the OP in AI Servo focus mode?

nope, quite certain i was in one-shot mode. i had a number of checks i performed while waiting for the rest of the folks to show up, and that was one of them.

"Multi-point" AF mode still only uses ONE autofocus point. You're just telling the camera - "I don't care where you focus"

ONLY reason to use "multi-point" is in AI Servo as the camera will start with the center point, and then "track" the subject using the other points if it drifts from the center.

ANY other situation, YOU need to explicity select the ONE autofocus point.

My 24-70L is tack sharp. It sometimes "misses" focus only because you have to realize that the actual area covered by each sensor is quite a bit bigger than the little red "dot" in the viewfinder.

The 7D (supposedly) fixes this "issue" with its spot focusing mode.

on the bright side, i was smart enough to shoot in large jpeg + RAW format, so i have copies of all these images in CR2 file format. i've never really gotten in to raw image editing before, but i figured for such an event, now was the time to jump in, just to make sure i had my bases covered should the photos not turn out all that well. i just finished downloading and installing DPP (not sure what everyone else around here uses, but DPP was in my current price range after spending big coin on this lens ), and found the "show AF point" option under the view menu. click on that, and for this image.....

http://img169.imagesha​ck.us/img169/4364/img5​269i.jpg

two points (of the 9) are lit up red.... the one on the far right, and the one in the lower left corner (by the three little girls with the lighter colored coats). not sure if this makes any sense or not, as zooming in on the image, even those portions of the image aren't really in focus.... still very soft.

egordon99 wrote in post #8812472
"Multi-point" AF mode still only uses ONE autofocus point. You're just telling the camera - "I don't care where you focus"

ONLY reason to use "multi-point" is in AI Servo as the camera will start with the center point, and then "track" the subject using the other points if it drifts from the center.

ANY other situation, YOU need to explicity select the ONE autofocus point.

thanks. that is helpful. i'll add that to my photog learning scribble notes. i studied up as much as possible prior to this event (which focal length to use, distance from subject, sweet spot/aperture of the lens i chose, etc), but i obviously thought that multipoint AF was the best option, basically due to the fact that there are faces "all over the map" in the image, and i wanted them all to be in focus, not just the one that i used center point focus to focus in on. misunderstanding on my part, i guess.

The 24-70mm is obviously not a prime. But you should expect quality approaching that of one... If there's any doubt, send it to Canon for a calibration check (and adjustment). You'll be out a lens for a week and it might run you $95 or so out of warranty - but at least you'll know what the deal is.

I just LOVE my 24-70mm. It might not be my favorite lens, but it sure is my most-used!

looking at the line-up in your sig line, that's saying something.

dipps wrote in post #8812549
i obviously thought that multipoint AF was the best option, basically due to the fact that there are faces "all over the map" in the image, and i wanted them all to be in focus, not just the one that i used center point focus to focus in on. misunderstanding on my part, i guess.

The way to get them "all to be in focus" is to select the appropriate aperture for your desired depth-of-field.

egordon99 wrote in post #8812737
The way to get them "all to be in focus" is to select the appropriate aperture for your desired depth-of-field.

for that particular lens, was f/5.6 too shallow?? i chose f/5.6 as it's supposed to be the sweetest range as far as sharpness is concerned on the 24-70mm (as with most lenses actually), and i figured for only 2 rows of people, f/5.6 should have been just fine. even so, at least SOME of the faces should have been in focus and sharp (were it a DOF issue). my thoughts anyway.

5.6 should've been enough at the distance that you were standing at, people correct me if im wrong

Like everyone else is saying, that looks looks like a focusing issue. Try manually focusing on something to see if you can get sharper results. Not sure how well the live view works on the 450D, but that is also a good method for manual focus testing when fully zoomed in. The lens could just be front/back focusing.