I bought this for my Canon EFS 17-55 mm f/2.8 IS USM. I am still using it on the same lens and is doing a very good job without distorting or altering the images. Great stuff

Mine securely holds my 6d Canon, 24 2.8 lens, 50 1.8 lens, and 70-200 lens with room to spare for extra items like flash, battery or lens filters.It fits comfortably on the back, and I've kept it on all day with no problems.I give it four stars because it does not stand up straight when you put it down on its rubber padding. The bottom of the bag is not steady enough to support the bags weight distribution and isn't flat so the bag will fall over.

Still Canon's best versatile zoom! Despite the less-than-glowing official reviews, this new 24-105 is a worthy purchase. I've owned the Mark I version three times, the 24-70 f/2.8 II, and the 24-70 f/4. My major disappointment with the f/2.8 II was lack of IS. Halloween and Christmas pics were next to impossible to get without toting a tripod around. The f/4 was very nice since it had IS, but I still missed that 105mm!I just recently purchased the Tamron 24-70 G2, which is a fantastic lens (f/2.8 and Vibration Compensation), but guess what...I missed that 105mm! So, decided to buy this lens, and after a little bit of AFMA, the lens is superb! Quick focusing, sharp images (much improved in corners), and lets in more light than the previous version.No, it doesn't have 2.8, but the IS is better than the first version, so that helps tremendously with slow moving subjects. You can shoot everything from wide landscapes to head and should portraits with nice bokeh. Yes, you lose some quality when compared to the 24-70s, but that is pure physics. This is the best compromise between image quality and focal range in my experience.I uploaded some pics I took today. These were not processed in post, just shot in Landscape picture style, and converted to jpeg in Canon's DPP.

Incredible 2.8 lens and I was using my old 60D. Can’t wait to use it on my new Canon 5Ds!

About a year ago I bought the EF 70-300mm f/4-5.6 IS USM lens. At the time, it appealed much more to me than its (more than three times the price) "big brother" - the lens did well for me but left me wanting MORE! I just got this lens, EF 70-200mm f/2.8L IS USM. It is worth every penny - those of you who have used an IS lens before will know what to expect in that regard, however if you have never owned a lens with canon's "L" glass, you are in for a treat! The color and image quality are far above the cheaper canon line. And the fixed f/2.8 is a fantastic advantage to have. I do mostly indoor concert photography and this lens has been a dream come true. (i know that sounds lame... check one out and you will see what I mean.!) If the fixed f stop isn't that big of a deal to you, im sure the f/4 is probably a good lens as well....however I can definitely say that this was a smart buy!

The walkaround lens. This very topic leads to a heated discussion among DSLR photographers.First, determine your budget, focal length, and aperture needs.If you frequently find yourself zooming out to get everything in a frame, you will want a wide angle lens such as this. If you frequently find yourself zooming in, this is not the lens for you. On a full frame body such as Canon EOS 5D, this lens becomes ULTRA wide angle. On an APS-C crop body such as Digital Rebel XTi (which I used for this review), it becomes MEDIUM wide angle. But thanks to 1.6x crop factor, this lens expands to more usable 35mm equivalent focal length of 27 to 64mm.Second, audition the lens if you can.By definition, a walkaround lens should be relatively portable. At 1.1 lbs., Canon's EF 17-40mm f/4L USM is neither super light nor neck breakingly heavy. In fact, it weighs almost the same as Digital Rebel XTi -- really nice balance. The lens feels very solid with supreme build quality that only L-series lenses offer. Although this lens is weather proof and therefore sealed against liquid and dust, I strongly recommend getting a 77mm filter to protect the front lens element. With it, this lens is made to last.In terms of looks and feel, it doesn't get much better. Its rubberized full-time inner focus manual ring USM focuses smoothly, quietly, and quickly. Since it's inner focus, the lens will not extend beyond its metal casing whether you zoom in or out. The focus window shows focusing distance from 0.28 meter (0.92 feet) to infinity. The focal length marker indicates 17, 20, 24, 28, 35, and 40mm. The lens exudes quality from tip to tip.You may tolerate heavier lens or may not mind lesser build quality of cheaper lenses. A walkaround lens will be used very often, so make sure you will be comfortable with it.This lens is famous for saturated color and deep contrast. Its images are simply stunning. At 17mm wide angle, barrel distortion is noticeable but relatively mild. From 24mm to 40mm, its images are distortion free and perfectly suited at capturing people.Vignetting (corner darkness) is minimal with mild chroma abberrations (color shadows). At f/4 aperture, details become noticeably softer toward the edges. The center region is very sharp and at f/5.6, edges remain fairy sharp. Thanks to 7 diaphragm blades, this lens can produce very nice bokeh at 40mm (blur effects).One of the most cited weaknesses is the f/4 aperture. In my experience, a bump in the ISO speed and steady hands are all you need to take well focused images indoor. On the other hand, if you are shooting with very little amount of light, you might wish for f/2.8 or image stabilizer. Although the difference between f/4 and f/2.8 is just 1 stop, my other lens, Canon EF 24-70mm f/2.8L USM (too heavy to be my walkaround lens) easily outperforms in such challenging situations. But by and large, I was not handicapped by the f/4 aperture.Some of the main competitions (sorted by price):- Sigma AF 17-70mm f/2.8-4.5 DC macro: Good zoom range with macro, and generally solid performance if you can get a good sample. It does suffer from a bit slow focus mechanism, soft corner, and chroma aberrations. Works only with EF-S mount.- Sigma 18-50mm f/2.8 EX DC: Very good value for f/2.8 aperture, but Tamron's 17-50mm is a bit better lens overall. Works only with EF-S mount.- Canon EF-S 17-85mm f/4-5.6 IS USM: This "traveler's lens" has a wider focal range than most wide angle lenses (widest among Canon) and is equipped with an image stabilizer. While it is a Jack of many trades, it is the master of none. Every lenses on this list will perform better at particular focal length. Then again, none of the lenses on this list has as wide focal range. It is famous for extreme barrel distortion at 17mm and chroma aberrations. Works only with EF-S mount.- Tamron SP AF 17-50mm f/2.8 Di II LD Aspherical (IF): This is the most direct competitor. It takes sharper images with faster aperture while costing less. Both the build and focus mechanism are significantly worse, but should be good enough for many. Works only with EF-S mount.- Canon EF-S 17-55mm f/2.8 IS USM: This is THE reference, if you can afford it. Its images have razor sharp details and great performance all around (minus vignetting, which is typical of EF-S lenses). The build quality is worse than L-series but still pretty good. Works only with EF-S mount. This is the best EF-S lens hands down.- Canon EF 16-35mm f/2.8L USM: One of the most expensive wide angle zoom lenses. It's larger and heavier, but has f/2.8 aperture.This is how Canon EF 17-40mm f/4 USM stacks up.Pros:- Among the very best build quality.- Excellent, buttery smooth, super fast front-focus system.- Top notch color and contrast. Very sharp center resolution.- Almost non-existent vignetting, generally low distortion, and well controlled chroma abberrations.- Ideal weight and size for walkaround purposeCons:- Edge softness at f/4 aperture.- Narrower focal length than most competing lenses.- Slower than some third party lenses.All in all, this is an excellent wide angle walkaround lens. It may not offer the most bang for the buck, but if you value full frame compatibility (EF lens mount) and excellent build quality, this is the default choice. This lens comes with a nice pouch and a lens hood. I find the hood to be somewhat ridiculously shaped and because the lens is resistant to flare, I do not use it often when shooting outdoor.

Worked well with my Canon 70-200 2.8 IS lens on a recent African Safari.

It tried this lens after my 16-35/f2.8 was stolen. It's a great value compared to Canon's other L series lenses. If you don't need the extra speed of the 2.8 lens, I highly recommend it. The only possible con I could come up with is that it is very light compared to the 16-35, which could imply something about its durability, but that's pure conjecture, and I can't subtract a star for that. It could simply be that the 16-35 contains more glass to accomplish the 2.8 aperture.