I don't know how Tamron has done it, but they made a great thing even better. There's a 'new' version of the 18-270mm Super Zoom lens. This lens might hold the record of longest zoom in a single lens, and this all includes Image Stabilization or as Tamron puts it VC - Vibration Compensation. I admit Tamron's VC is very very effective and much quieter than most of my Canon IS lenses.
This is a highly recommended lens by me when i'm looking to travel light on vacations. I get the best wide and super duper zoom features in a single lens (NOTE: not for full frame cameras). Below is a snapshot of my 60D with the original version of the Tamron 18-270mm.
So what's great about the new version? New motors make the lens more silent and faster. Smaller too. Yes, as if they couldn't make a 270mm Lens any smaller, they've managed to cut down the whole package another 24%. Obviously this all translates to being even lighter than the original version too. I know, you're curious about Video quality. I loaned my original version out to a friend and had a hard time getting it back, he loved it so much. Here's a sample video below shot during his trip to China on the 'older' 18-270mm @24fps.
The Video above is a good example of how far this lens zooms out to, so that you can grab a few 'stolen shots' or use it for 'stealthy street photography' without your subjects even knowing. Now you're wondering about Photography. What is the difference in zoom from 18-270mm? Here's two examples I shot in a Museum, one at 18mm on a Canon 7D and the other at 270mm (handheld too - love the VC).
Above: Image shot on Canon 7D at 18mm
Above: Image shot on Canon 7D at 270mm
Overall this lens won't give you the most incredible shallow DOF as a single Prime lens would, but once you have it in your hands, it's hard to let go. The convenience of carrying a single lens with the amount of zoom range and very effective Image Stabilization makes this one of my favorites. And for the first time, this new lens version is now available in a Sony mount (not just Canon / Nikon).
Image stabilization or 'IS' is what Canon calls it, Vibration Compensation or 'VC' is a Tamron term, and Anti Shake 'OS' a.k.a Optical Stabilization is Sigma's phrase. Yeah that last one didn't match up very well, but it's an all important feature for today's run and gun hand held DSLR video renegades. It's also going to provide you with sharper images in low light situations when you can't use flash. When photographing with an Image Stabilized lens, you can also keep some of that ISO noise down. Sure a fast F/2.8 or better will help get that light through, but Image Stabilization is equally as important. Which lens is right for you? In today's economy, that question often comes down to 'What price is right for you'. So what's the options for Wide lenses between 16-55mm with a fast F/2.8? Here's the top three for Canon DSLR's (not full frame).
First is of course Canon's 17-55mm with IS. Some say it's super sharp, and built with such quality it should be labeled with other 'L' class lenses, but Canon doesn't seem to stamp L on any of their EF-S mount. Of course, it's also priced close to other L lenses so it's above what some young shooters want to invest.
Canon EF-S 17-55mm F/2.8 IS Zoom
I'm going to throw off the order of things and skip down straight to most inexpensive. If you're looking for the cheapest price, Tamron has been doing well with today's market and offers a 17-50mm F/2.8 with VC (Vibration Control) that has worked very effectively for me on my 18-270mm. Some may argue it's not better than Canon, but I find that the VC with Tamron is super quiet compared to the IS on some Canon lenses (especially the 24-105mm).
Tamron SP AF 17-50mm f/2.8 XR Di-II VC
Here's the middle ground in the top three list of fast wide lenses offering Image Stabilization. Although i'm talking about Canon options, keep in mind that both the Tamron and Sigma are available in other makes such as Nikon and Sony. The Sigma 17-50mm F/2.8 is still incredibly cheaper than the Canon 17-55mm and just slightly more than the Tamron 17-50mm. This is one of Sigma's recent lenses offering a 17-50mm F/2.8 with OS. Sigma's been getting great reviews as of late, and their designs keep getting better. Normally Sigma's are way over priced compared to the Tamron brand, but in this range of lens it's not a huge difference. Personally I think Sigma has an edge in quality of glass and build so if you could afford to, this Sigma is a great option for a fast wide with optical stabilization.
Sigma 17-50mm F2.8 EX DC OS HSM Zoom Lens