Is my EF-S 17-55mm a lemon?

[oqs]

I bought a EF-S 17-55mm from CP-M a few days ago. While testing it at home, I took some text near to the lens' minimum focusing distance (still able to AF confirm) and found that there is big amount of chromatic aberration (CA) at the edges of the image (yellow fringes on the left side of a letter and blue fringes on the right). In the centre, CA is less obvious but still visible. After correcting the CA in Camera Raw, the image appears to be sharp. Can anyone tell me if this behaviour is normal for this lens?
Please see the cropped images at 100% below. I have attached an image from the EF-S 18-55mm as reference. Compared to my 17-55mm lens, the kit lens seemed to exhibit no CA at all.

17-55mm @ 55mm f2.8

17-55mm @ 55mm f5.6

18-55mm @ 55mm f5.6


Would like to call out to anyone with the same lens to do the simple test too. Shoot some text and then 100% cropped out the text at the edge of the frame. Do post here if okay.

My main questions here will be:
1) Is this amount of CA acceptable for this lens?
2) Is my lens showing some signs of a bad copy?
3) If it's NO for the above, can I go back to CP for a 1-to-1 exchange since it's still within 7 days?

Thank you for your time.

 

[oqs]

No reply guys and girls?? Am I missing out any information here or are the questions I'm asking too ridiculous? Do let me know. Thanks!

 

[An drew]

Looks like a lemon indeed.

 

[playplay]

No reply guys and girls?? Am I missing out any information here or are the questions I'm asking too ridiculous? Do let me know. Thanks!

Mounted on tripod? Any filter attached?
It seems to me that your focusing is underexposed as well. How abt doing another series of shot in a brightercondition.

 

[doom102938]

If you mount the camera on a tripod, remember to off IS

 

[oqs]

Oh yeah, forgot the setup. Camera used was 40D mounted on 190XPROB tripod. B+W UV filter on the 17-55mm and Tokina UV filter on the 18-55mm. Subject was about 40cm away from the mount, pasted flat on a wall. Will try to do another series with +1 to exposure. Thanks for replying.

 

[night86mare]

when life gives you lemons, make lemonade :heart:

there's always a blender around

 

[oqs]

very 'deep' leh. Got simpler version? haha

 

[night86mare]

very 'deep' leh. Got simpler version? haha

er, just trying to cheer you up.

i suggested putting your lens into a blender if it was a lemon. :angel:

please do not do it though, it is just a joke. later you take me seriously then jia lat.

 

[oqs]

haha. thanks. But I will definitely not try that. Blended glass probably don't taste good.

Still looking for sample pictures by anyone owning a sharp/good copy.. and all comments still welcomed.

 

[twitism]

haha. thanks. But I will definitely not try that. Blended glass probably don't taste good.

Still looking for sample pictures by anyone owning a sharp/good copy.. and all comments still welcomed.

ok bro if i have time i'll do it later when i get home

 

[oqs]

Thanks a lot, twitism! Really really appreciate it.. Look forward to seeing your test pics if you do have the time to take today.

 

[playplay]

Yeah, pls remove off filter before you do any comparison. Filter might affect lens quality. Cos u r also comparing 2 different filter with 2 different lens in the above.
Pray hard that there isnt such effect after that..

 

[oqs]

Thanks. Will try again tonight without the filter and properly expose the frame.
Anyway I got a feeling the frame is actually properly exposed but vignetting caused the darkness because this is cropped from the edge of the frame.

 

[oqs]

I have retook these test pictures after removing the filters from both lenses and upping exposure to get a brighter picture. Please see below for the test images at 100% crop.

17-55mm @ 55mm f2.8

17-55mm @ 55mm f5.6

18-55mm @ 55mm f5.6

It seems to me that the CA is affecting the sharpness of the 17-55mm. After correcting the CA in photoshop, the image looks really sharp. Is this amount of CA inherent to this lens? Or am I getting a bad copy?

 

[TYM76]

Have u tried sending in to CSC to do some focus tests? When they check its better

 

[twitism]

hi
sorry i got home really late so i juz took 2 quick shots

hope it'll help

55mm @ f2.8

55mm @ f5.6

 

[oqs]

twitism, thanks for your help. But I'm having problems seeing the images. Is there a problem with the linking?

 

[calebk]

Definitely quite the lemon you have there. However, I'm not sure if this CA can be corrected through any calibration process at CSC, or whether they will entertain an exchange.

You may want to make haste if an exchange is required though. Most shops only entertain that exchange policy for a week.

 

[twitism]

twitism, thanks for your help. But I'm having problems seeing the images. Is there a problem with the linking?

done. was on picasaweb but i changed to flickr. should work liaoz