Canon EF-S 17-85 f/4-5.6 IS USM 100% crops and samples

PERSONAL OBSERVATIONS:

Canon EF-S 17-85 f/4-5.6 IS USM produces sharp images when viewed whole on high-resolution monitors, HDTVs, or 8X10" (203X254mm) enlargements without much need for post processing. It's nice to have 17-24mm wide-angle coverage when foot zooming is not possible; however, images from this range can get a little soft when viewed at 100% with unacceptable amount of chromatic aberration and barrel distortion. Thanks to Adobe engineers, these shortcomings can easily be corrected during Photoshop RAW processing.

This 5X zoom is ideal for travel and general use, and for stationary subjects the three-stop Image Stabilizer delivers f/1.4-2.0-equivalent blur-free images in low-light situations.

F-stop breakdown: 17-24mm f4, 24-35mm f4.5, 35-47mm f5, 47-85mm f5.6

Wide open, the lens is pretty 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.

Adjusting White Balance is also best done in RAW.

Under difficult lighting situations, more details can be captured shooting RAW.

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.