Need help testing Canon 17-55 vs 17-85

[tk303]

Hey guys,





So I just got my copy of the 17-55 after lots of forum reading about it. After viewing the sample shots on this website comparing the two lenses I had expected a massive increase in IQ compared to the 17-85 but after doing a few test shots I can't seem to see much of a difference.


I tested them with my canon T2i on a tripod at same focal lengths and same apertures. I manual focused them using live view to make sure the focus was right.


Here are two shots:


[img]/resized-image.ashx/__size/550x0/__key/CommunityServer-Discussions-Components-Files/8/1200.test-1.JPG[/img]


This one is the 17-85


[img]/resized-image.ashx/__size/550x0/__key/CommunityServer-Discussions-Components-Files/8/0358.test-2.JPG[/img]


This one is the 17-55





Now I wanted the f2.8 for indoor shots but I was also hoping for better IQ.


I'm not sure if I have a bad copy of the 17-55 or a really good copy of the 17-85 (probably not)


Or is it just the way I tested it?





I would just like to be sure it's not a bad copy before my return period expires.





Thanks guys

[neuroanatomist]

Hi, and welcome to the TDP forums!

I tested them with my canon T2i on a tripod at same focal lengths and same apertures.

Sorry, but are you certain? The framing is different (the 17-55mm is shifted to the right, but even compensating for that, the 17-55mm framing is slightly tighter - that may be due to imprecision on the zoom ring markings - check the EXIF data). Also, the OOF area appears blurrier with the 17-55mm, suggesting the aperture is wider (again, check the EXIF - if the same, the 17-55mm is delivering more background blur).


Image quality is difficult to judge in a 550 pixel-wide forum image - a common convention is to post 100% crops from center (assuming that's where you're focusing) and corner (framed identically so we're looking at the same part of the image). Also, to check corner performance, you really want a subject that's flat, so the corners are in the plane of focus (or focus on a corner with 10x live view).


--John

[neuroanatomist]

Ps. I

[tk303]

Thanks for the reply John,


You are 100% correct. I accidently posted the wrong photos of the handheld shots I did outside.[:$]


Ok so I've just done another test:


This test is 100% crop 17mm f4 on a tripod.


[img]/resized-image.ashx/__size/1000x0/__key/CommunityServer-Discussions-Components-Files/8/8611.100_2500_-crop-17mm-f4-17_2D00_55.jpg[/img]


This is the 17-55


[img]/resized-image.ashx/__size/1000x0/__key/CommunityServer-Discussions-Components-Files/8/7713.100_2500_-crop-17mm-f4-17_2D00_85.jpg[/img]


This is the 17-85





I know the crop is slightly different from each other but I didn't think that would matter.


The crop was center and about 20% to the left of the image.


I hope this is a better sample to show thew IQ of the lenses.





Thanks for your quick response.

[neuroanatomist]

To me, the 17-55mm image appears to be sharper and also has better contrast and saturation - pertty much what I would have expected. I'd expect even greater differences in the corners, where the 17-85mm performance is reportedly not so great.

[Jon Ruyle]

I

[tk303]

I guess it is a little sharper.


I was just hoping for more of a difference like this:


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


If you scroll down to the 17mm test at f4 there is a huge difference between the two lenses.





I know it's not really a <span style="background-color: #ffffff;"]L lens and not a prime <span style="background-color: #ffffff;"]so I can't really compare it but when I got my 100mm f2.8 macro L the first photo blew me away compared to anything I had.


<span style="background-color: #ffffff;"]I guess I was just expecting too much from this lens.





<span style="background-color: #ffffff;"]Thanks for all your feedback