I won't make this review lengthy, because it's all been said before, but I will qualify myself by saying that I depend on photography for approximately half of my income, and I recently purchased this lens after many hours of online research. I own a Canon 7D, and I was looking for a lens that would fall into the wide/portrait range with the 7D's 1.6x crop factor. This lens was bought as a replacement for my old Tamron 28-75, which was a respectable lens. The Canon 17-40 has thus far been a very solidly built, light, fast-functioning lens. It autofocuses VERY quietly with its ultrasonic motor, and the autofocus is very accurate. On the 7D, I have found it to be a capable portrait lens at 40mm, as well as a great lens for interiors. I bought it as a complement to the Canon 70-200L, for a lightweight kit, and while I am missing the 41-69 focal range, I haven't really needed it. The lens produces VERY SHARP photos, and is much more reliable in quality than the Tamron. I would definitely recommend it to 7D users wanting a versatile walkaround lens, or to full frame users looking for an ultrawide with great sharpness.

I use this lens primarily for video on a Canon 7d Mark II. This lens provides silent, fast and accurate autofocus for video.

I bought this used through Amazon. It sees duty on a 5D Mk III and 7D Canon. I like it!

I love this extender, my 200 becomes a 400....and on my canon 7d, it becomes a 560! Quality is excellent, however you need a lot of light, best for shooting outdoors.

Works flawlessly with the Canon 7D. Wireless function is fantastic; no need to buy a wireless transmitter if you own a 7D. Overall very satisfied with this purchase.

So good I bought 3 of them for my cameras. One I have adapted to fit Canon 7D attached to Sigma 50-500mm lens and it all fits great.

I used this flashgun with a Yongnuo radio transmitter for TTL portrait photography using my Canon 7D Mark 2. My set-up previously used the 7D Mark 2’s built in flash gun as an optical trigger for a Canon 580 EXII in a soft box and a 430 EX II shooting into an umbrella. The optical trigger system was fairly unreliable indoors, as it relies on line-of-sight and was hopeless outdoors.It was such a relief to use these flash guns via radio triggers instead. It took about 30 minutes to set them up, allocating a unique flash ID to my system (my birth date!) and linking each to the on-camera flash trigger. The instructions were quite well written. I was then able to shoot away to my heart’s content, knowing that I could put the flash guns anywhere I want to.In terms of build quality, these are a good imitation of the Canon 600 RT flashgun. My 580 EX II flashgun has far higher build quality, which is easily apparent when tilting the flashgun head or locking onto the hotshot bracket. However, in practice, they yield very similar results at 1/7 of the price. This makes it a reasonably priced purchase for amateur photographers seeking to set up a simple, portable home studio.

Needed this as I lost the body cap for my Canon 7D. It came pretty quickly and most importantly, FITS perfectly. Thanks Amazon!