Brendon: I used this lens at an all day wedding in lighting situations from outdoor, full sun, indoor dim, indoor window light to night time near-darkness reception. After reading many reviews online by main concern was the sharpness and vignetting. After looking through the images I'm happy to say that the lens is perfectly sharp, no complaints whatsoever in that department. My normal kit is a 50mm f/1.2L, 35mm f/1.4L and 70-200mm f/2.8L IS, so the sharpness standard was pretty high. The reason I rented this lens was the I've been dying to see image stabilization in a workhorse standard zoom other than the 24-105 and had also read good things about Tamron's system. After using it all day I can say that the stabilization is surprisingly good WHEN it's activated. It locks in much quieter than my 70-200 and the correction is somehow subtle yet effective. However I did have one big problem, and that was that the lens doesn't seem to activate the VC system, even when it's switched on, until it senses some pretty severe shaking. My hands are pretty steady, but I do shoot very rapid fire, and moving around alot while I'm shooting tends to give me some camera shake in the pictures, but the Tamron didn't seem to sense my movements as enough disturbance to turn on the VC most of the time. When I finally figured this out, I started locking in focus then shaking the lens around a bit and seeing the VC lock down, and then it worked great, easily down to 1/50th, but practically, this wasn't really a situation I could live with. Last note, towards the end of the day I was in a very dark reception room and the lens's low light focusing performance was surprisingly bad. On my 5D MK3 with L glass attached I've been spoiled by finding focus quickly in even near darkness, but found that I couldn't nail shots quickly at all with this lens attached and ended up going back to my 35mm after awhile. Definitively fun to play with, and would be a great walk around lens for (daytime) exploring and travel, but as an event photographer, I won't be buying one.