17-55mm f/2.8 IS soft at wide open

[piyomaru]

Just got a quick question for the expects in this forum. I just purchased the

17-55mm f/2.8 IS but is a bit disappointed at the sharpness of the lens at

wide open. For example, the following shot is taken at f/2.8 @ 17mm with

center point focusing focus locked to the eyes. The picture looks fuzzy to

me. Is there problem with my camera or my lens? Please help!<div></div>

[bob_osullivan]

What was your shutter speed? I'm assuming this was shot handheld. Also, what ISO. Actually this shot looks fine to me. He looks sharp enough. If you are refering to the teddy bear in the background, that's just due to the shallower depth of field at F2.8. Maybe you are just not used to that. Also, at wide open Aperture, zoomed to the wide end, any lens will have it's poorest porformance. Do a search on how to test out a lens properly before drawing any conclusions. I think your's is probably just fine.

[jimstrutz]

EXIF data says Canon Rebel XTi f/2.8 and 1/60 @ 100 ISO in program mode. With IS on it should be sharp.

 

The small version shown looks sharp enough at the eyes, but it's hard to tell without seeing a 100% crop. You can turn up the camera's internal sharpening if you want, or use USM in post processing. But the real question is, how does it print?

[mendel_leisk]

Any lens will be softer wide open. Couple this with increasingly shallow depth of focus. So if you're comparing against shots where you've stopped down, you will invariably see softer results in the wide open shots.

[PuppyDigs]

Show us a pixel level crop of the face and we can actually judge the sharpness. Like others

have said, DOF is shallow at F2.8 so anything outside the plane of focus will be soft. If you

need sharpness beyond the plane of focus, you need to stop down.

 

Individual copies vary somewhat. However my 17-55 2.8 is deadly sharp at F2.8. It's a wee

bit sharper in the middle range but still amazingly sharp. The main reason I use F2.8 is for

shallow depth of field. I want the background soft. However you'll get the most of this feature

on the long end of the zoom.

[piyomaru]

For the one asking for the full size crop of the picture, here you go. I would like to say that I also did the focus test with my camera at f/2.8 @ 17mm too and it seems to be back focusing, can this be the problem?<div></div>

[picturesque]

Looks like it missed the focus. Check the rest of the image to see where the focus landed--it could even have landed in front of the subject, and you won't see it. The image is too fuzzy to be the slightly less sharp wide open aperture.

[piyomaru]

Here is the picture of the focus test, f/2.8 @ 17mm, center focus point focus locked to the "focus here" text line.

[piyomaru]

Hi Nadine, the problem is most of the pictures I took at f/2.8 @ 17mm looks like the picture I have attached and that's why I am worried and wish to get expert opinion from the users at this website.

[andys]

To me, it looks like it's not focussing correctly. The focus chart you have posted seesm to be in focus about 6-10mm behind the plane you wanted.

 

I'd get this combination of Lens/Camera looked at.

[piyomaru]

Andy, I have the same focusing problem with my kit lens at f/3.5 @ 18mm, I suspect that it has to do with my camera calibration. I do not want Canon to only tune the 17-55mm IS + camera calibration, I want the camera body to be properly calibrated so that I can get consistent focus even for future lens purchases, how should I go about doing this with Canon?

[mendel_leisk]

Hard to tell with my eyes, but I think the little guy's ears are a bit sharper, and the focus chart test seems similarly shifted.

[peter_rowe]

If you send your camera and lens to Canon for calibration they do not calibrate just one to the other. They calibrate them independently using your camera with a known good 50mm lens, and your lens with a known good camera.

[picturesque]

Mendel might be right--maybe the T-shirt right behind his head is more in focus. In any case, to avoid having the lens and body calibrated to each other, send the body in first. Canon will do as Peter says--calibrate the body to a known good lens. Then send in the lens and they will do the opposite--calibrate it to a known good body.

[beauh44]

I agree: The sharpest part seems about a 1/2 inch behind the eyes. I'm sure it won't be convenient but I bet after a focus "tune-up" that'll be a pretty sharp lens, even wide-open.

[piyomaru]

Well, thank you all for all your help. I'll be sending in my camera and lens for calibration since they both are less than 2 months old. The funny part is that the reason I purchased the 17-55mm is because I was not able to obtain reasonable sharpness from the kit lens. If the problem really lies in the calibration of the camera body, I guess I should be able to get usable pictures from the kit lens too.

[mearle_gates]

I hope you aren't judging the sharpness based on a handheld photo.