PERSONAL OBSERVATIONS:

Canon EF-S 17-85 F4-5.6 IS USM

This lens produces sharp images when viewed whole on high-resolution monitors, HDTVs, or 8X10" (203X254mm) enlargements without much need for post processing. However, images from the 17-24mm (27-38mm equivalent) range can get a little soft when viewed at 100% with unacceptable amount of chromatic aberration and barrel distortion. Although these shortcomings can easily be corrected during RAW processing, I avoid shooting at the widest range to cut down on the time spent on post processing. This lens does perform much better in the 24-85mm (38-136mm equivalent) range.

The 27-136mm equivalent range is ideal for travel and general use.

F-stop breakdown: 17-24mm F4, 24-35mm F4.5, 35-47mm F5, 47-85mm F5.6

The bottom line is: there are better options on the market now!

Wide open, the lens is relatively sharp in the center, a bit soft at the corners with lots of chromatic aberration at the wide end. Using RAW + JPEG setting is highly recommended since removing the WORST CASE of chromatic aberration and corner softness is as simple as typing "-50" in ACR "Fix Red/Cyan Fringe" setting and "50" in "Sharpness" setting. See the 17mm RAW-PROCESSED image below.






17mm (27mm) F6.3 1/80sec PP resized. Less than a minute was spent on reducing chromatic aberration and sharpening.



85mm (136mm) F10 PP resized. This lens is very sharp at the long end.



85mm (136mm) F5.6 1/20sec PP resized. 85mm (136mm) is perfect for portraits.
 
 

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