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Author Topic: Did I get a bad copy of the EF-S 17-55 f2.8?  (Read 1252 times)

arjay

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Did I get a bad copy of the EF-S 17-55 f2.8?
« on: September 10, 2013, 06:15:20 PM »
I just received my “new” refurbished  EF-S 17-55 f2.8 from Canon.
Really excited, until I began testing the lens and comparing it to my 18-55  kit lens.

The 17-55 is touted as being a great lens, please tell me if the one I got is merely lousy
or if this is typical.

I've done a bunch of boring tests,  but here are some comparisons of the 17-55 compared to the kit lens at f5.6. 

The 17-55 is sharper in the center.

The 17-55 has less CAs

The kit lens is sharper with less distortion on the edges at all focal lengths.

Is this a bad copy?  If so  I'll see if Canon will exchange it.
What is other people's experience?

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Did I get a bad copy of the EF-S 17-55 f2.8?
« on: September 10, 2013, 06:15:20 PM »

Random Orbits

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Re: Did I get a bad copy of the EF-S 17-55 f2.8?
« Reply #1 on: September 10, 2013, 11:47:45 PM »
The 17-55 has been AFMAed, right?

Pi

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Re: Did I get a bad copy of the EF-S 17-55 f2.8?
« Reply #2 on: September 10, 2013, 11:57:44 PM »
The 18-55 is pretty sharp already but does not have great contrast. The 17-55 is not particularly sharp near the borders at f/5.6 but it is worth the money, IMO.

The 17-55 has less DOF at the same f-stop, in my experience. Make sure you are comparing well focused parts of the image.

ahab1372

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Re: Did I get a bad copy of the EF-S 17-55 f2.8?
« Reply #3 on: September 11, 2013, 01:12:38 AM »
The 17-55 has less DOF at the same f-stop, in my experience. Make sure you are comparing well focused parts of the image.
Not sure if I'm misunderstanding this: are you saying that the 17-55 has less Depth of Field than another lens at the same focal length and same aperture (on the same camera)?
I though that was not possible, unless I'm missing something.

dgatwood

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Re: Did I get a bad copy of the EF-S 17-55 f2.8?
« Reply #4 on: September 11, 2013, 01:13:59 AM »
The 17-55 has less DOF at the same f-stop, in my experience. Make sure you are comparing well focused parts of the image.
Not sure if I'm misunderstanding this: are you saying that the 17-55 has less Depth of Field than another lens at the same focal length and same aperture (on the same camera)?
I though that was not possible, unless I'm missing something.

It's possible if one lens is lying about the f-stop.

ahab1372

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Re: Did I get a bad copy of the EF-S 17-55 f2.8?
« Reply #5 on: September 11, 2013, 01:24:57 AM »
To the OP: the crops you posted look a bit dissapointing, but at f/5.6 or higher most lenses become more and more equal in terms of sharpness.

Here are two links from TDP with comparisons, maybe that helps to see if your copy falls into the expected range:
http://www.the-digital-picture.com/Reviews/ISO-12233-Sample-Crops.aspx?Lens=398&Camera=474&Sample=0&FLI=0&API=0&LensComp=763&CameraComp=0&FLIComp=0&APIComp=0

http://www.the-digital-picture.com/Reviews/Canon-EF-S-15-85mm-f-3.5-5.6-IS-USM-Lens-Comparisons.aspx


dswtan

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Re: Did I get a bad copy of the EF-S 17-55 f2.8?
« Reply #6 on: September 11, 2013, 03:02:16 AM »
I have always been disappointed by my 17-55's sharpness, even with AF MA -- plus mine has the dust ingress flaw*. It performs like yours. I assume we have bad copies, because surely all those anecdotal rave reviews can't be wrong... (the more systematic tests could be more reliable).

I'm sure bad copies occasionally happen. I didn't know any better at the time and so I never changed mine. It might be worth a try, if you have that option.

*http://www.pbase.com/lightrules/drp

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Re: Did I get a bad copy of the EF-S 17-55 f2.8?
« Reply #6 on: September 11, 2013, 03:02:16 AM »

eddiemrg

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Re: Did I get a bad copy of the EF-S 17-55 f2.8?
« Reply #7 on: September 11, 2013, 03:48:03 AM »
The 18-55 is pretty sharp already but does not have great contrast. The 17-55 is not particularly sharp near the borders at f/5.6 but it is worth the money, IMO.

The 17-55 has less DOF at the same f-stop, in my experience. Make sure you are comparing well focused parts of the image.

15-85 bad contrast...? Why...?
Canon 7D - 50 f/1.8 - 70-200 L f/4 IS USM - Canon 15-85

Pi

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Re: Did I get a bad copy of the EF-S 17-55 f2.8?
« Reply #8 on: September 11, 2013, 08:14:23 AM »
The 17-55 has less DOF at the same f-stop, in my experience. Make sure you are comparing well focused parts of the image.

Not sure if I'm misunderstanding this: are you saying that the 17-55 has less Depth of Field than another lens at the same focal length and same aperture (on the same camera)?
I though that was not possible, unless I'm missing something.


DOF based on aperture is just an approximation. There is a well known Zeiss document

http://www.zeiss.com/c12567a8003b8b6f/embedtitelintern/cln_35_bokeh_en/$file/cln35_bokeh_en.pdf

about DOF and bokeh, where they explain and actually measure the loss of sharpness away from the focal plane for different lenses, see p. 23 and 35 (upper right) there.

Also, away from the center, things can change even more.

I noticed this effect when I tested both lenses, but I do not keep the photos, and I do not own those lenses or  crop camera anymore.
« Last Edit: September 11, 2013, 08:17:04 AM by Pi »

Pi

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Re: Did I get a bad copy of the EF-S 17-55 f2.8?
« Reply #9 on: September 11, 2013, 08:19:18 AM »
I have always been disappointed by my 17-55's sharpness, even with AF MA -- plus mine has the dust ingress flaw*. It performs like yours. I assume we have bad copies, because surely all those anecdotal rave reviews can't be wrong... (the more systematic tests could be more reliable).

My 17-55 was excellent at close distances, like 2-3m but not spectacular near infinity.

ahab1372

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Re: Did I get a bad copy of the EF-S 17-55 f2.8?
« Reply #10 on: September 11, 2013, 09:10:39 AM »

DOF based on aperture is just an approximation. There is a well known Zeiss document

http://www.zeiss.com/c12567a8003b8b6f/embedtitelintern/cln_35_bokeh_en/$file/cln35_bokeh_en.pdf

about DOF and bokeh, where they explain and actually measure the loss of sharpness away from the focal plane for different lenses, see p. 23 and 35

Looks like an interesting read, thanks for the link

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Re: Did I get a bad copy of the EF-S 17-55 f2.8?
« Reply #10 on: September 11, 2013, 09:10:39 AM »