17-55, 17-85, 15-85 Dilemma

FWIW, I don't think I've heard of the 17-85 being sharper than the 15-85.

I don't have the 17-85, but reviews have stated that it tends to be weak from 17-20. If you need a lens for that, then you might gain a lot with the 15-85. However, you already have the 17-55, and it might be better to spend the money elsewhere.

17-55 > 15-85 > 17-85.

I have had the 17-85,, tamron 17-50, sigma 17-70 and the canon 15-85. The best range was the 15-85, sharpness I would go with the tamron. The sigma 17-70 was soft. I actually went full circle and have the newer kit lens, 18-55 (is)......I found the canon 15-85 to best the best iq/range, but it's way to expensive and heavy. I am actually thinking about find a other tamron non vc.

cbkoontz wrote in post #16566936
Any thoughts on the sigma 17-70 f/2.8-4 as a faster alternative to the 15-85 while still maintaining most of the range?

Actually, it is a great lens. I had it for a while - it maintains F 2.8 through a big part of the focal range, and adds more range to the 17-55. Excellent sharpness, contrast, etc. Many people here on POTN have only good opinion about this Sigma 17-70.

Echo Johnson wrote in post #16567916
FWIW, I don't think I've heard of the 17-85 being sharper than the 15-85.

Looking at the sample archive threads and my own photos, I think this is probably true, though the difference does seem very small and possibly not worth worrying about. I think I will eventually get a 15-85, mainly because the IQ seems so much more "lively". The extra 2mm at the wide end will come in handy too. I shall go on thinking about it for a bit though. My 17-85 is actually sharper than my 17-55.

Even though I never tried the 17-85, as I own the 15-85, it is worth noting that the former one is offered for sale used at around US $200, while the latter - for around $500-$600.

I've got the 17-85 and the the 15-85.
Distortion at the wide end of the 17-85 is worse and if suffers from quite a bit of CA. Both of which are easily corrected in PS. IF you're a pixel-peeper the 15-85 is sharper. In normal viewing my eyes can't really pick the difference between the two. The 17-85 has had the ribbon cable and the aperture assembly fail on separate occasions. It's been repaired and has been handed down to my teenage daughter. The difference between 15mm and 17mm at the wide end was significant enough that I delayed getting the 10-22 for almost 2 years.

In my opinion only. I have both the 17-85 and 15-85. The latter is a better lens but the difference is not worth the price of the upgrade. Why don't you look at spending a bit more and augmenting your range with a 10-22 instead? It compliments the lenses you already have and the quality of the images is first rate, comparable to your 17-55 that you like so much. I love mine and would never part company with it.

Thanks, darwindan. You are reading my thoughts exactly! Do I go for that small increase in IQ with the 15-85, or the 10-22? I have always fancied the latter and, if there isn't really much difference between the 15-85 and the 17-85 at the longer ranges, perhaps I would gain more by going for that wider angle lens. In fact I'm pretty sure I would.

The Canon 17-85 is prone to autofocus failure. The problem is with a ribbon cable inside the lens. Mine has failed twice. Other users on this forum have reported the same problem. The first time it cost about $150. The second time I bought a 15-85.

I don't know if Canon has redesigned the lens to fix this problem. But if you count the cost of one or two repairs, it might be cheaper to get the 15-85, which in my opinion, is an optically better and far more useful lens. I don't think anyone on this forum has reported a similar problem with the 15-85.