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.

This UV filter has been a great addition to my Tamron 35mm for my sony. This filter is definitely more of a protector than a modifier at least in my use case, it helps to protect the exposed focusing mechanism of the lens and makes sure that no dust or particulates get into the lens. Overall I would say that this is a great filter to put on any lens as it adds a barrier between the front element and the world, and I didn't notice any negative effects on image quality by having this filter on the lens.

after years of sticking my lens cap in my pocket I finally lost it while hiking in soft sand dunes, I probably didn't hear it fall. This replacement fit perfectly. The problem with the Tamron lens cap is that the stick on lens keepers don't work on these, there is no place to put the sticky dot. The one thing I have never liked about my Tamron lens was there they was no lens keeper string for the lens cap.

I bought this filter for my Tamron 17-28mm e-mount lens and love it. I haven't noticed any major color distortion and the sharpness doesn't seem to be affected at all either. The low profile seems to negate most vignetting you may encounter, but it does show up (unsurprisingly) if you stack this with another filter like a CPL. The gold ring is a nice touch too. I would absolutely buy these again as you get great results for the money.

Fits perfectly to my Tamron Aspherical 28-400mm lens

Purchased mostly as extra protection for my Tamron 150-600mm lens. Fits fine and does what I want it to do. Good value.

I bought this for my new TAMRON lens. Fits perfectly and will provide the protection I need.

I had the Tamron lens for almost two years and it made me so disappointed! 90% the indoor pictures was out of focus and blurry.The Tamron lens only took good picture outdoor. Within these few months I bought three Canon lens and they all meet my expectation. Today I received my first L lens and I was totally happy with the result. I will say 60% the pictures was sharp with detail, 35% was acceptabe and maybe 5% was blurry during my randomly shoot.This lens was focus fast without hunting the object like the Tamron Lens with the loud noise.The Tamron lens made you like a fool when you took picture with the peoples in a low light environment.This Canon lens consider a bargain with a great result. My camera was Canon T3i and I used a 27 inches Samsung monitor to view it.