Pro: Great image quality, especially for available light portraits shot at f2.8 where you want a pleasingly blurred background. The IS is good but see note below.Con: Weight if you plan on carrying it around all day on a pro camera body.This is a great lens and if I didn't also own the 70-200mm f4.0L IS Canon lens I would have rated it 5 stars. IMHO the f4 is a better all around carry lens if you don't absolutely have to have the f2.8 aperture. The IS in the f4 is Canon's latest and is usable up to 4 stops slower shutter speed than you'd normally need at less than half the weight. The 2.8 version uses the very good, but older, 3 stop IS. On the surface you would think that the f2.8 aperture being one stop faster would place them on even ground where IS is concerned but it does not. the newer IS on the f4 version is INCREDIBLE in operation! To be fair to the 2.8 lens, given the same lighting conditions, it gives you one full shutter speed faster that may make a difference if stopping motion is needed in the shot. My best advice is to not end up with both lenses becuase it is so hard to decide which one to take along!

I purchased this to replace my 16-35mm L lens that cost about twice as much. I am very pleased with the clarity this lens provides... especially for the price!

Works awesome on my 16-35mm II. I realy love the colors on my photos when I'm using it

I've used this with my 35mm f/1.4 E-Mount . By far, this polarizer has not came off my lens when i took it out for travelling to Hawaii. It gave my shots more contrast, darkens the highlights to the point where I can use the image and of course, see through reflections. As a polarizer, it does what most polarizers do, I definitely would recommend this filter!Highlights:- Tiffen helps with maintaining the sharpness- Blocks reflections- Ups the contrasts in your shots and reduces highlights

I have the 16-35mm F4, and indeed the extra 2mm help a bit....but as far as IQ I can't say there is much of a difference.If you have already a canon 16-35mm f4, then there is no need to get this one ( I got it because the 16-35 is now under my wife's fingernails)The 15-35 f2.8 it's different story, if indeed you need 2.8, but same applies to the 2.8 EF variant - 1mm difference.In sum, a great lens, way more compact than my 11-24mm, similar performer as the superb EF16-35mm f4, but as a first UWA or replacement from a 17-40 for instanceRecommended

Isn't the Carl Zeiss optics lens as advertised but it;s a much clearer picture now so... I got that going for me, which is nice.

I have had this fabulous lens for 2 months now. This is my second lens in Canon's line up of L lenses. I have a 70-200 f4 non-IS also. This is my first wide angle zoom L lens and i have come to know what i have been missing. Till now the widest lens i had was a 50mm f2.5 macro and 50 f1.8. Although on a 1.6x sensor like 20D which i own, this lens is not so wide it performs excellently. The focusing is very fast, sharp crisp images and consistent quality as the aperture range remains the same throughout the entire zoom. This may not be suitable for some the semi-pros or pros since its a little slow being f4, i would recommend this to anyone who does serious photography as a hobby. In indoors too it performs flawlessly. Most of the time i dont use a tripod and its difficult to maintain a fast enough shutter speed especially with aperture more than 8. so if you are like me, then you may want to take a look at the 17-85 IS or the 17-55 IS since the IS compensates atleast 2 stops in low light for hand holding. But if its outdoor then u can easily handhold this and shoot some great photos in good lighting conditions. Also i would like to mention that being a L lens this is a little heavy because of its solid construction. Its also big compared to the other startup lenses. It takes 77mm filters and it can be used even on full frame cameras like 5D. hope you enjoy this lens as much as i am doing.

Great bang for your buck forsure, i use this on my sony 16-35mm g master