my 17-55mm IS vs 50mm 1.4, results and Question, is my 17-55 soft???

I have the time to take a difference between my 17-55mm is usm and my 50mm 1.4

the results are very strange, my 50mm beats my 17-55 in 2.8 or 4.0 aperture, so do you think my 17-55 is a bad copy and needs calibration or just the lens is soft that way??? i test it over and over with my 17-55 but still give that soft image,..

the test image and point where i crop 100%:

Results (left is 50mm, and to the right is 17-55mm): (my 17-55mm focal length is 52mm Exif still there)
@f/2.8

@f/4.0

I would assume that the 50 1.4 stopped down to f2.8 would be sharper than the 17-55 wide open.

However, to me, the 17-55 looks a little soft to me.
Used a tripod correct? (1/6 shutter speed is a giveaway I guess)

I know the 17-55 is tripod sensing, but did you try with IS off?
Did you use timer/remote with MLU for these shots?

or maybe that's the power of the prime lens,..

nicksan wrote in post #4949647
I would assume that the 50 1.4 stopped down to f2.8 would be sharper than the 17-55 wide open.

However, to me, the 17-55 looks a little soft to me.
Used a tripod correct? (1/6 shutter speed is a giveaway I guess)

I know the 17-55 is tripod sensing, but did you try with IS off?
Did you use timer/remote with MLU for these shots?

IS is OFF and tried with IS on but no luck..., and i use RC-1 carefully not to get shake, and still get the soft image,..

I tested my 17-55 against my 50 1.4 as well and my 17-55 was better at all similar aperatures. I used a tripod and MLU and used a focus test chart from a magazine. I was surprised at the results. Looks to me like you have a soft copy.

irishman wrote in post #4949687
I tested my 17-55 against my 50 1.4 as well and my 17-55 was better at all similar aperatures. I used a tripod and MLU and used a focus test chart from a magazine. I was surprised at the results. Looks to me like you have a soft copy.

omg , sad to hear that,.. but still under warranty,

calibrate hm..,... if i have the time to do it, how long will that take time???

paten wrote in post #4949429
the results are very strange, my 50mm beats my 17-55 in 2.8 or 4.0 aperture, so do you think my 17-55 is a bad copy and needs calibration or just the lens is soft that way???

Seriously, this is not a surprising result. At f/2.8, the 50 is stopped down two entire stops. So you've got a stopped down prime vs. a wide-open zoom?? Of course the prime will mop the floor with the zoom. Even with the zoom stopped down one, the prime is getting into its, well, prime image making area. You won't beat it with a zoom until you get to f/8 or so where you might not be able to tell the difference.

That is prime vs. zoom.

Oh and you need to do a focus calibration test on the zoom to make sure it is focusing in the right place. That is impossible to tell without seeing the full 100% image from the zoom, which you have not shown.

Try manually focusing the zoom and see if it improves.

Yeah, your 17-55 does look soft. Definitely try higher shutter speeds and see what you get.

The think that really confuses me is that on the shot of area #3. The 50 seems to get sharper on the right side, which seems to indicate back focus (since the cd case is round)....where was your focus point?

TheHoff wrote in post #4949766
Oh and you need to do a focus calibration test on the zoom to make sure it is focusing in the right place. That is impossible to tell without seeing the full 100% image from the zoom, which you have not shown.

uploading ,..

Davidoff wrote in post #4949803
Try manually focusing the zoom and see if it improves.

trying it..

bacchanal wrote in post #4949828
Yeah, your 17-55 does look soft. Definitely try higher shutter speeds and see what you get.

The think that really confuses me is that on the shot of area #3. The 50 seems to get sharper on the right side, which seems to indicate back focus (since the cd case is round)....where was your focus point?

at #1 at the letter "S"

i'm trying to retake the iamge with manual focus this time, and hope it works

tried it:
same results,..

Here's a shot from my 17-55 and 40D:

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If I want to compare know how sharp my lens is, I will never shoot in low ( poor ) light. I will do everything possibe to eliminate all variables, leaving only the lense sharpness in question.

Sunny day, use sunlight or shade.
Place on tripod
Cable release.
Check for focus error