You can get excellent sharpness and great soft backgrounds with this lens. It's quite a stunning thing to see photos with this lens shot with a little XSi. Once you have enough skill to get your modes set right you can be shooting portraits, animals, flowers, product shots (I do a lot of that) and a ton of other great stuff with this bit of glass.If your shooting a crop body like I do, you'll need a wide angle lens for those landscape and indoor shots where this thing doesn't get wide enough. I use a Sigma 20mm f/1.8 for those times. It's a great standard lens for crop bodies, the sharpness and depth of field effects you can get from opening up that big 1.8 aperture are stunning.But this Tamron zoom is no slouch either when it comes to bokeh and sharpness. Stop it down to 4 or so and in decent light it will give you excellent sharpness, contrast and color. I find I seldom reach for the 20mm except when I want to get right up next to a flower or insect or maybe a piece of jewelry in a product photo, open the aperture and get really smeared backgrounds.You can do that with the Tamron. But the Sigma seems to produce the better backgrounds in those situations. You just have to get real close and personal with the camera.Last fall we were camping at a local reservoir in central PA during the height of the fall colors when I found a huge spider in a fully formed, quite beautiful web. It had recently rained and the web had a lot of those nice dewy droplets on its filaments. I was able, with this Tamron, to get very close to spidey and web, choke off a lot of depth of field and soften the water and multicolored trees in the background to a beautiful palette of color with only hints of shape. That was one of the best series of shots I've ever taken, and it was with this lens. Stopped down a bit to give more form to the background and spidey was in a whole new light.This lens works for weddings and birthdays, school plays, picnics, tourism, whatever.If you need more zoom than this, maybe you should buy a telescope. I can see needing a wider lens than this, but if you can't zoom close enough, shoot RAW and enlarge. This zoom range is perfect for 90% of my image composition within the range it shoots.It's much easier to compose than with my 20mm Sigma prime. Any prime lens will have you walking around, backing up, moving in, trying to get that frame right. The payoff is unbeatable sharpness and speed per dollar.However, this 2.8 zoom lens is plenty fast, and very sharp as well.I bought this lens a couple years ago for under $400. The Sigma prime cost more than that, and I only use it for about ten percent of my shots.This thing is so far beyond the price in terms of capability, that I will buy another one if this one ever breaks.Recommended. 

Question: How is the build quality like?
Answer: backgrounds