Very quiet motor and fast focus for a wide zoom

This being said, with most of the new DSLR's such as the Canon 7D and greater, you can fine tune the focus for each lens, using the in camera fine tune adjustment feature.

sharp pictures ,have a silent and fast focus

This lens has Auto Lens Vignetting correction using peripheral Illumination control see Auto Vignetting comments belowButtery smooth zoom and manual focus ringsFits all Canon EOS cameras including full frame film and 5DFirst copy I got was good to go with no quality control issuesSharper on the wide end 17 to 24mm then Canon EF-S 17-55 F/2.8 IS and Canon 24-

If you like and want to produce images in which large foreground objects play against smaller objects in the background while all remain in sharp focus, an ultrawide lens is a necessity

you can actually fine-tune the focus with greater accuracy

one thing i do really like is the ultra fast, ultra quiet auto focus

Easy to use and super easy focus manual or auto

Pro: excellent picture quality, great picture contrast, smooth focusing motors, excellent glass quality

The focus and zoom rings are super smooth and feel great

Pros:- Among the very best build quality.- Excellent, buttery smooth, super fast front-focus system.- Top notch color and contrast

I continue to be impressed with the sharp high contrast photos and the super fast auto focus

Pros:- Among the very best build quality.- Excellent, buttery smooth, super fast front-focus system.- Top notch color and contrast

Built to last forever with smooth zoom and focusing and they came with a lens hood and carrying bag.

The focus and zoom rings couldn't be smoother and AF is fast.

Under darker conditions, the focus seems a little slower than my other faster lens, but even at f4, it takes crisp shots

All of them required slight micro-adjustments inside the camera to get perfect focus.

Rapid focusing (with sufficient light)L-quality buildReasonable weight and size (solid but not unwieldy)Sharp!Tight focal range - can get within 6-9" of a subject with the right light

PROS:1)Excellent build quality2)Ultra fast auto-focus - the USM (ultra sonic motor really works very well)

I took a portrait at full zoom of the same person (40 mm or 65 mm equivalent and 85 mm or 135 equivalent), cut out the critical focus area from both pix and equalized the two crops in terms of pixel numbers

Its fast focusing abilities are amazing

It does suffer from a bit slow focus mechanism, soft corner, and chroma aberrations

Sharp, fast Auto Focus, great build, looks good, feels good and delivers the quality image I expect from an "L" series lens

In my experience, a bump in the ISO speed and steady hands are all you need to take well focused images indoor

great image, great performance, fast focus, perfect shape

Also although it isn't an f 2.8 as like the 16-35 it does have a bit more

It's a very capable landscape lens on my 6D, but it isn't quite as crisp as a 24-105mm L that I used to have, even in the F/7.1 - f/9 "sweet spot