need help from experienced 24-70mm users

ok, i've been waffling back and forth between the 24-70mm, 24-105mm, and 17-55mm for the past month. i shoot a rebel xsi (crop, and yes, i know most would recommend the 17-55mm for my xsi, but after much consideration, i chose the 24-70mm.... it just fits what i do better).

i hadn't planned to buy any of the lenses for a while yet (still biding my time, choosing my next lens carefully), but my wife went and volunteered me to do a group photoshoot for both our families (thanks, wifey). i was the last to know. my lenses are as shown below (the 24-70mm 2.8 isn't yet in the list). my best "20 person group portrait" lens prior to the 24-70mm was the 18-55mm IS (or maybe the 50mm 1.8). i went and tried a few practice shots with my kit 18-55mm, and wasn't real happy with them. with 20 people depending on me to get a good family pic, i wanted to do a good job (and no, i wasn't charging anything to take this pic, or the numerous other "single family" pics i took before and after the group pic). i figured with this family shoot, my own family shoot, and my best bud and his wife wanting me to do a family pic of them, it was the best time to break down and bite the bullet on my next lens. i chose the 24-70mm 2.8, despite knowing it's history of "bad copies"/people going through 3 or 4 copies before getting a good one. i hoped that wouldn't happen to me.

i don't think i was one of the lucky ones.

long story short, most pics came out ok (as far as the family was concerned), but after studying this lens and sample images from sharp copies of it for the past 2 months, i KNOW this lens is capable of more. and i'm not a pro photog, i just do this for fun (for now.... maybe someday when i really learn all that i need to know), so spending $1300+ on new lens is a major purchase!

i bought the lens at mike crivello's nearby (milwaukee, wi) and in speaking with the folks there, i asked what they knew about this lens and "bad copies". they told me they knew nothing of such things..... told me that they didn't think there was such a thing as bad copies for this lens, and that pro wedding photogs bought that lens from them all the time, and none have ever been returned. i said, "that's great, but what if i do get a bad copy, and i want to return it for a good copy?" originally they were talking at me about 15% restocking fee, and i got a little angry at that point. i made it clear i had no intention of spending that kind of coin on a new lens from them if i was going to have to pay them $160 some dollars to return a "bad copy". eventually they said they'd take care of me were i to wind up with one, so i bought the lens.

so long story short, i did the shoot, and even on my 3" LCD i was getting the suspicion that the images weren't really all that "sharp". i even got the "err99" message once while trying to shoot first time i had ever gotten that message. i powered off the camera, powered it back up, and it shot fine from there on out (no more error messages).

but looking thru the pics, i don't see anywhere near the level of sharpness that i should be seeing from this expensive lens. heck, some of the pics (many) look like they were taken with a point and shoot, as far as sharpness goes.

the details:
i was shooting with a good, sturdy tripod, and a remote trigger, so handshake was not the issue.

for the image below, i was shooting with the following settings (which SHOULD have been right in the sweet spot for this lens, according to all i've read):
- f/5.6
- 1/125 sec
- ISO 400
- 40mm (right around the middle of the focal range)
- spot metering
- image was taken from a distance of maybe 15-20 feet away

the image is a 100% crop taken from the full image (6.6mb in size), only showing the heads. pretty sure you can see the softness that i'm talking about by looking at this pic (especially looking at the lady's face/hair). if you're interested in helping me out and want to see the full size pic, shoot me a pm and i can host it on my website to view.

i have 10 days to take the new lens back if indeed it is a "bad copy".

thanks for looking, and thanks in advance if you can help me out, verifying or negating that i do indeed have a soft copy.

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Well, I think that this is an unacceptable level of quality. I own the lens and I have never seen anything like that without being user error.. being said that it is on a tripod with a shutter release, I think you have a bad copy.

I don't think that the store will ever admit to knowing about "bad" copies of the lens, but I'm sure if you use the search function here, you will find that many people have had trouble getting a good copy... I am one of the lucky ones.

You have some primes that should compare with what should be the acceptable quality of the 24-70.

Posting more images would help. The sample you have posted appears to be out of focus. Where was the focus point in that picture? It could be that the lens is front/back focusing.

Agree.. I would use something other than humans

Use a ruler some type of grid with numbers and patterns that would give you something more concrete to base you test on.

Looking at that photo my expectation is that it is out of focus. There is nothing in the image that lets me see the area in front and behind the subject to tell for sure, but that is how it looks.

So:

1. If you can confirm that the two folks there are absolutely at the point of focus then the lens is soft.

2. If you play around some and determine that they are not in focus, but the lens AF systems seems to usually place the subject out of focus then the lens probably needs to be calibrated.

Yeah it does look out of focus, sure it wasn't focused on something in the foreground? Put on centre point AF, focus on a wall at an angle or something and take some shots - if it's sharp then some part of the wall should be in focus and sharp, and if the AF is working as it should then the wall at the centre of the shot should be in focus and sharp.

I use an XSi with a 24-70. It's a great combo. Things to remember though. The middle focus point is the only one worth a darn. If you want a lens like this to shine, know your focus. Even if you have a "Bad Copy", Canon will take care of you with this. I would not be pressured to take it back.

joayne wrote in post #8809092
You have some primes that should compare with what should be the acceptable quality of the 24-70.

THIS is what i'm used to seeing with my primes (attached below). i don't expect the 24-70mm to be completely on par with my 135mm, but it should be closer than the headshot image above, from all that i've read (i've heard sharp copies are nearly on par with a 70-200mm f/4).

i focused in on at LEAST the upper chest, if not the head on the image above (trying to be completely honest, recalling from memory here). i know i originally set the exposure by metering on the face, but adjusted to take into consideration all elements in the picture. i can get tack sharp images with my 135mm w/o even trying, i'd expect at least somewhere in the vicinity with my 24-70mm on a tripod......

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Looking at the full image above can you see where the camera focused or is the entire image soft?

also, is there any merit to what this guy is talking about?

http://www.slrgeek.com …ns-review-comparison.html

sounds like his was going out of calibration every other month or something.....

Jeff81 wrote in post #8810445
Looking at the full image above can you see where the camera focused or is the entire image soft?

here's a slightly downsized version of the full image (half the original size)...... hard to tell because if i focused on the chest, it's a dark sweater.

http://img67.imageshac​k.us/img67/4164/img529​5k.jpg

btw, thx for the help guys. much appreciated. was a serious downer when i looked over the images and was not seeing what i was hoping for from a $1300 lens. need to get this sorted out. i honestly don't THINK it's user error (as mentioned, i've been taking plenty of pics with the 135mm and 85mm without any issues), and i'm not exactly new to this, but stranger things have happened i guess.

If you focused on the two people's trunks, there was little to nothing for the camera to see with any real contrast. The autofocus systems need contrast for them to decide whether or not the image is in focus. The backlit situation makes it even worse.

Try some testing on subjects with normal contrasty lines for focusing and lit normally (NOT backlit) before you make any rash decisions.

here's one of the group shots i took. again, tripod shot, multipoint AF. aperture at f/5.6, 1/125sec, ISO 400, 34mm.

2000x1333 image below
http://img169.imagesha​ck.us/img169/4364/img5​269i.jpg

by this are you saying that the appropriate action (if indeed it is a bad copy issue rather than a user error issue) would be to send the lens back to canon rather than take it back to the dealer who sold me the lens?