Very sharp
Good contrast
Nice colours
Good control of distortion
Moderately wide on 1.6 cropped sensors
Works on full frame
Very wide on full frame.
Well built
Now about half the price of Canons 17-40 in the UK.

Flare prone.
Difficulty using filters.
Weird AF/MF switch mechanism.
A bit noisy.
Relatively slow at max aperture.

I bought this a few years ago for use with my Canon 10D. At the time it was just about as wide as you could go on a cropped sensor camera (24mm). I have overall been very pleased with its performance. It is very sharp corner to corner even on my newer 5d (certainly more so than my 17-40L), has a very pleasing colour rendition and and has ample contrast.
Zoom range and aperture are a little limited but I knew that when I bought it- Not a problem for landscape use. Distortion is well controlled considering its ultrawide field of view on full frame.
Build quality, while not as good as Canons L lenses is still high. It is a bulky lens but doesnt feel that heavy. It lacks a HSM and focusing is a bit noisy though perfectly accurate.
There are a few annoying issues with this lens however. It has an odd and cumbersome mechanism for swithcing from auto to manual focusing involving a switch and a push-pull mechanism on the lens barrel, a 2 step process. There is a fixed petal type lens hood which precludes the use of screw in front filters. On a cropped sensor camera, low profile filters can be attached to the press-on lens cap holder without vignetting but on full frame cameras, filter use is impossible.The front element is very bulbous and potentially easily damaged.
For me its biggest problem is flare. Its not unusable but needs great care if there is a light source within or close to the frame. If care is not taken this flare is often associated with significant loss of contrast.
Overall I'd say its one of the sharpest ultrawide zooms available, produces very pleasing pictures if you are willing to work around its foibles. Its performance on a 5D (at least my copy-sigma have a reputation for variability) is better overall than the 17-40L and much better than the Sigma 12-24 which I also tested. It does however need careful use to avoid flare and filters have to stay in the bag.

Customer Service

N/A.

Similar Products Used:

Canon 17-40L, Sigma 12-24, Canon 24-70L.

Tack sharp - this is all thats important to me
large, but lightweight
easy to use
Bright veiw.

No facity for fitting filters. i have a wide thick rubber ring on the lens cap casing to take a Cokin Pro 100mm filter holder adapter to acheive this, it works fine, but it would be nice not having to. Filter fitting very wide.

I've used this lens for architecture at the wide end, correcting perspective in PS. Pics are tack sharp. Also I used in a group shot portrait, unfortunately heads at back appeared narrow, this lens would work on groups if poeple were in one plane.
The lens comes into it's own in landscape photography where you want tack sharp from foreground to horizon. Best seated on a tripod, slow shutter and as small aperture as possible, say f22.
The only reason I would have to sell this lens would be if I required a more expensive nikon.

Similar Products Used:

Tamron 20mm lens on a Canon AE1

Looks and feels good and solid and is easy to zoom. Nice wide angle.

Images just not sharp and crisp, even at F11. Hard to find proper focus when dealing with infinity shots.

I returned my first Sigma 15mm to 30mm EX DG lens by priority mail on Monday (Virginia to New York) and received my exchange lens from Cameta Auctions (eBay) by UPS on Friday morning! Kudos to good customer service! Now for the disappointing news. I spent over 4 hours messing with this lens over the weekend and am returning it for either a refund or possibly paying more to try the Sigma 10-20 mm (going to look at reviews first). The 15-30 was just not sharp enough for me at wide focal lengths as a landscape type photographer (I hang my cameras from a tethered blimp to do low-level aerials by remote control www.crowsnestphotography.com). I loved the wide angle, but found that even at F 11 was unable to get things crisp in photoshop. I shot high level JPEGs for some, but mostly decided to do RAW to bypass internal camera sharpening going to jpeg. For many of the tests a tripod and tripping the shutter using the self timer w/ 2 second delay was used, but if I can't hand hold the camera and shoot at 250/sec or faster and get a clear shot, try thinking of it swinging off the blimp! The lens was impossible to "point and shoot" focus using the camera's autofocus (Pentax * ist D), or manually focusing with the camera beeps as confirmation of my "I think it is focused" aging eyesight. Since the entire image would be blurry, I finally decided to fix the f stop and started at the 'racked' end of infinity (at 15mm focal length), and shooting the same scene, slowly manually turned the focus ring millimeter by millimeter to "bracket focus" to see if the lens ever got sharp. I could get ALMOST acceptable results at F11 one one of the 5 shots taken at that setting. This would be fine for private snapshots but not for paying work. This time I didn't even try to do closer than infinity type shots. Interesting to note, the serial number was only one larger for this exchanged lens. Could there be a "Monday morning production run" syndrome? Again, the only reason I am with the Pentax digital is I have tons of 645 lenses and am waiting for them to put out there MF digital they have been promising. Also, the 645N and lens is a VERY heavy monster to lift on the blimp so was enjoying the 20% weight saving combination of the * ist D and lens. My original wide angle 18-55 kit lens that came with the camera broke on me and I am still waiting for it's return.

Customer Service

Cameta Auctions (on eBay) has been excellent so far.

Looks and feels good. Easy to zoom/focus. Nice finish and doesn't feel "plastic".

Image quality. Hopefully just a fluke. Will give them one more try.

Having worked at Canon's technical camera USA hotline before, I knew that Sigma can make a decent lens for the price. I am 'stuck' using Pentax (*ist D) equipment due to $20,000 worth of 645 lenses I own so I didn't switch to Canon equipment when going digital. Price is important at this time so elected to try this lens. I was VERY disappointed to say the least. Closeup photos are acceptable, but from my test shots, when approaching the 'infinity' distances (all shots manually focused), the lens at ALL F stops, was blurry. This was noticable at either 15mm or 30mm. It was noticable especially on the right 1/3 of the image. While I think the lens looks and feels professional, the images were terrible. I am in the process of swapping it out as there has to be something wrong with this individual lens. Will see how fast Cameta will respond.

Similar Products Used:

Sigma 28 to 300.

solidly built, relatively low price tag (but for that quality...), quite low distortions (but worse than 12-24)

severe (corner-)softness even stopped down to f8-11, only usable for smallest prints; problems with qc (bad centered); no HSM/USM

After having used much my Sigma 2,8/18-50EX (an excellent lens so far!) I decided to go a little wider... and bought a 3,5-4,5/15-30 at ebay. The price seemed very ok for a lens like this at only 249 Euro (about 300 US-$), BUT used on my Fuji S2Pro (Nikon mount NAF) the 15-30 exhibited many flaws: terrible corner softness even stopped down, center sharpness not too good either below f5,6; a little too big for being only 3,5-4,5, and a "front-cover-philosophy" you really have to get used to (ring+cap). Besides that the centering was quite bad (right side much worse than left, a very common problem though with "cheap" glass especially from Sigma). Bokeh is not too beautiful either, but that may be not so important for a wide-angle imo. So I will probably sell it again on ebay (how many of these are circling around there?) and look for something more convenient, maybe a Tokina 12-24...

Customer Service

not used yet

Similar Products Used:

Sigma 12-24 CAF (not sharp wide open, but nearly distortion-free; perfect for architecture stopped down to f11-16), Sigma 2,8-4/17-35 EX DG NAF (really bad wide open, better from f8; AF-Problems, went back to dealer), Sigma 2,8/18-50EX NAF (a much better lens, use it most), Tokina 3,5-4,5/19-35 CAF (can't beat it for the price, sharp and well built), Sigma 18-125 MAF (better than the 18-200, but heay vignetting + distortions; sharp!), Tokina 2,6-2,8/28-70 CAF (good only at f8 and smaller apertures, very solidly built), Sigma 2,8-4,5/24-135 CAF/NAF/MAF (quite good, the best allrounder for lower light situations), Tamron 3,5-5,6/24-135 NAF (the best allrounder - if you get a good sample!)

the build, price, quality, and performace is all good..

none that i can find yet..

after have read all of these reviews here, i bought myself this sigma 15-30mm, i took it to my california trip for 5 days. i shot about 200shots with this lens..on my fuji s2 pro. the results were very pleasing..infact, its very nice..the sharpness is on par, colors are nice and bright, contrast is very good too, it seems abit on warmer side, i meant yelo casts..but that is true on almost all lenses or digital cameras..this size of the lens is huge, i leave the lens hood cap on at all time, to block side light, or anti flares..,i did get some flares shots, but that bcuz i shot toward the sun..that would happen on any lens too..other than that it gives me very good results..the sharpness is there, better than all the other wides i've got..the barrel distortion is not that bad at all..the build quality is solid and light weigh..i sold my new nikon g lens 18-55mm and nikon 24-120mm to replace with this, no regrets..in all, for the price its deffinetly a keeper, highly recommended. i personally love it..

Customer Service

none so far..

Similar Products Used:

nikon 18-55mm, canon 18-55mm..

price. Focal length for digital

lack of contrast/sharpness at certain (widest and narrowest focal lengths)

I thought I would give this lens a try after selling the 12-24mm Sigma which I found unacceptable. I definitely feel more confident with the quality that this lens offers (compared to 12-24) BUT I still find it substandard at certain focal lengths. For web use-no problem, but I would think twice before printing an A3 litho playout, NO MATTER WHAT MEGAPIXEL CAMERA YOU USE. I do enjoy it as a travel accessory, and event photography lens, though it is a bit slow.

Similar Products Used:

sigma 12-24 nikon 18-70

Wide focal length for those expansive landscapes or those tight interior shots. Good sturdy build. Sharp once stopped down f5.6 - f16

distortion, prone to flare, gelatin filter, soft edges, physically big

Wide - Wide - Wide. Not having anything wider than 28mm before, the view from 15mm is amazing. This lens is great for those landscapes as well as tight interior shots. Fairly sharp once stopped down 5.6 and above. Edges are a little soft, but acceptable for such a wide angle zoom. Plastic barrel, but not cheap feeling. Feels sturdy, but I wouldn't want to drop it. Nice metal hood that does a fairly good job at fighting off flare.

Customer Service

n/a

Similar Products Used:

Canon 20mm

Great colour (at least on my copy) Good zoom range for nature/city photography. Fair resolution.

Not the fastest lens in the world.

I bought the 15-30 for my Eos 10D and I have not been disapointed. It´s quite sharp and results in beautiful colours. In fact of all my lenses (and I´ve got a lot) it requires the least post-processing in Photoshop. It´s of course not quite as sharp as the best Canon lenses such as my 70-200 2.8 but you´ll get some good pictures with it.

Customer Service

None required

Similar Products Used:

Canon 20-35 2.8L

Very well built, sturdy and solid. Captures excellent images.

There is nothing that I don't like about it.

Sigma has made themselves a lens that fits the niche of wide angle zoom landscape photography at an excellent price. This is a great wide angle zoom lens that captures photos as well as it looks. Rugged build and really 'stands out' from the camera. As stated by someone else, this lens is an attention getter and because of its size, will really get you 'the look' from others. Great color capture and I'm pleased with the whole zoom range from 15mm to 30mm. Looking forward to getting out more with this lens for landscapes. Spring is on its way!

Customer Service

Not needed.

Similar Products Used:

None yet but I am looking at the 120-300mm EX APO HSM 2.8 zoom.