Sigma 28-70mm f/2.8 EX DG
(From Sigma lens literature) This compact and constant f/2.8 aperture zoom lens and is ideal for digital SLR cameras. Two SLD elements and four aspherical lenses provide correction against distortion as well as all types of aberration, especially spherical aberration. Its advanced optical design ensures high performance throughout the entire zoom range. The use of aspherical lenses in the construction of this lens not only corrects aberrations but also produces a very small and lightweight lens design. Its compact, yet robust construction has an overall length of 87.2mm (3.4 in.), maximum diameter of 74mm (2.9 in.), filter size of diameter 67mm and weight of 510g (18.0 ounces).
This lens offers a large aperture of f/2.8 over its entire range of focal lengths and its large depth of field offers greater freedom of creative expression. This lens is perfectly suited for low light conditions indoors or at dusk. It covers wide angle to medium telephoto and is ideally suited to a wide range of subjects.
Two Special Low Dispersion (SLD) glass elements are provided for effective compensation of color aberration, which is a common problem with super-wide angle lenses. Four pieces of hybrid aspherical lenses offer excellent correction for distortion as well as all types of aberration. Its excellent optical performance makes this lens ideal for Digital SLR Cameras as well as film SLR cameras. It incorporates "Super Multi Layer Coating" to reduce the influence of harmful light caused by reflections from the digital image sensor.
It has a minimum focusing distance of 33cm (13 in.) at all focal lengths and a maximum magnification ratio of 1:4.4, which is very convenient for close-up photography.
This lens is also equipped with a zoom lock that eliminates "Zoom Creep." This remarkably compact, high performance zoom lens is ideally suited for traveling.
Since the front of the lens does not rotate, a Petal-type hood and circular polarizing filters can be easily used.
Sigma 28-70mm f/2.8 EX DG User Reviews
8 out of 10 points and recommended by theflyingmoose (2 reviews)good value, decent optical performance, seems sturdyodd plastic, bit soft at f/2.8
As a replacement for a kit lens (even one that was as reasonable as Pentax's 18-55), this lens seems worthy of my investment. While I'm used to really sharp images through my elderly 50mm prime, changing from regular use of a kit lens (it being convenient and auto-focus) was an eye opening experience.reviewed February 15th, 2009 (purchased for $300)
This said, it is soft at f/2.8, not very badly, but enough that stopping down is usually in order. Of course, stopping down from f/2.8 still gives you more leeway than stopping down from f/4 or f/5.6. I have found though that f/8 is more like it for really sharp images (but this isn't unexpected judging by reviews of many lenses of this ilk). In all, a minor criticism really.
The lens seems well constructed, not a fabulous all metal affair, but nothing to complain about except the very strange texture, which is erm, shark-skin like? Difficult to explain, but its not going to stay pristine from the moment you put the lens on your camera.
While this is no replacement for a really good prime, I don't think anyone would suggest that it should be; but it covers a very useful range, and I have found it to be an excellent portrait lens, as it allows you to cover the important range (with the sensor crop) of about 70-100mm.
While sales literature will describe this as a lightweight and compact lens, that's only compared to a huge-range zoom I think, its much bigger and heavier than a kit lens (think bigger more expensive filters...). That said, the payoff for that weight is detailed above. If you want a really light lens, and you use Pentax, apparently their pancake lenses are excellent (though I've never had the chance to try one).
Overall, for the price, any minor complaints I've written here are pretty much moot - plus, dare I say it, having a wide barrel and a gold band, it makes you look like a big shot photographer :) Not that any of us would be so concerned about our image, only those which we produce!
9 out of 10 points and recommended by thomasjohnlynch (2 reviews)price, quality, speedno canon logo?
Being new to SLR 35 and having just an XTi I am very nervous about wasting cash or not getting any value or return on a "toy part" for this hobby. I took about 2,485 pictures last year and have save and been taking digitial photography since the mid 90s when my son was first born. I have been swapping out the plastic freebie and bought a Sigma 70:300 zoom for outdoor sailing and wildlife and now picked up this lens for close up and indoor and flash. This is a very well constructed, fast and accurate lens! Bought out here on Long Island for under $200 new. I also picked up a Bowers .42X fisheye to get a little bit more data in those close shots with just a hint of distortion, it has a Macro lens for this Sigma which just gives a more Swiss Army knife use to this lens. Picked up a Bowers SFD35C flash ($134.95) and some 2900mAh rechargables) after sticker shock on the Canon stuff. This lens and that flash work GREAT. Not sure how to post samples shots so maybe Ii can put that in my profile.reviewed January 6th, 2009 (purchased for $190)
7 out of 10 points and recommended by RonaldH (1 reviews)Nice constructionSlightly disappointing at f2.8
This lens is nicely finished and works flawlessly on my Nikon D70. Of course I don't have the test equipment to say anything meaningful about image quality compared to other lenses... with one exception. The point of lenses like this is their speed. If you need f2.8 you are going to use it. The difference between f2.8 and f3.5 is easily seen with this lens. f2.8 is much softer. Despite this I think it represents good value for money. Try it out for yourself to see if it fits your needs. I'm currently not tempted by alternatives.reviewed December 5th, 2005 (purchased for $329)