Sigma 10-20mm f/4-5.6 EX DC HSM

To clarify, I am not an expert, more of an advanced amateur, but there was no option for this, and I'm definitely above Intermediate. Also, I live in the UK so price given is in Pound Sterling.

I bought this on eBay from a reputable seller, even after hearing about Sigma's quality control issues. I had considered getting the Canon EF-S 10-22mm, but it was too expensive for my taste, and the Sigma provided everything the same (well, except for 2mm at the long end, but it overlaps nicely with my kit lens). Anyway, being part of Sigma's EX line, I decided to take the plunge and purchased it.

I received it about 3 days later, and, to be frank, I was astounded by it. The build quality is just fantastic. While it is made out of plastic, it is high quality and definitely doesn't feel cheap. It is also reasonably heavy for it's size. I prefer heavy lenses, as they feel more solid in my hand, and I seem to be able to hold them steadier for longer periods (I expect my arms try to compensate too much with the lighter lenses, by thinking the lens weighs more than it does, causing major shake).

I didn't get much of a chance to use it on the first day, so I just took some quick snaps to analyse on my screen. While I wasn't amazed at optical quality (to be fair, it was at 10mm at f/4) it was definitely sharp. The first time I really got to use this lens properly was on a trip to Cornwall. It definitely proved it's worth there, and f/8 seemed to be it's strong point. However, it does take a while to get used to composing images with such a wide field of view, and the fact that the viewfinder I was using was only 95% coverage meant I would continuously get things in the frame that shouldn't have been there (for instance, an image I took of Spinnaker Tower from the base while I was lying down had to be redone about 8 times because I kept getting the top of the Lifeguard safety buoy that was hanging straight above me). That was most likely due to my inexperience at the time.

Autofocus is fast and accurate, just like it should be. Though, not as fast at the Canon 10-22mm I tried on my camera, it got the job done quickly and smoothly.

Build quality. With my copy, this was definitely the strong point of this lens. I just cannot fault it. It's heavy enough to feel solid in the hand, and light enough to not be a chore to carry around. It feels like it could take a lot of beating, and also gives it an expensive feel.
Image Quality. Well, to an extent anyway. It's not the sharpest lens I have ever used, but I definitely wouldn't say it's bad or even average. Very good centre sharpness, which deteriorates at the corners (though quite heavily at larger apertures).
Price. One of the main reasons I purchased this lens. It is very generously priced, considering it's strengths.
Speed. Since it's a third party lens, I would say it's very good in terms of AF speed. However, in terms of aperture, It's not that good, especially for low light. But, the recently released Sigma 10-20mm f/3.5 lens is a good alternative to this if you want that aperture increase (and want to stick with Sigma. There are larger aperture wide angle lenses available).
'What's in the box'. It comes with a carrying case and lens hood, like many 3rd party lenses do. The lens hood is thick and solid, and case is nicely padded at the top and bottom.

Corner quality wide open. Corner quality at wide apertures is always a problem for lenses (for some it's much less of a problems than for others, but corners are generally weaker than the center), but the distortion on this lens definitely doesn't help much.
Distortion. Not the worst performer in terms of distortion, but it is quite high. In fact, any more and you could probably call it a fish-eye (ok, it's not that bad, but I'm just trying to give an example), so it's probably not the best choice for architectural photography.
Vignetting. At wide apertures, vignetting can be a problem.

Canon EF-S 10-22mm

Didn't have to use Customer service, and probably never will.

Astounding lens in every way, both price and quality. Even if the "big name" lenses bring better quality (how can they?), it's not an excuse for a price that's over double of this lens. And though inexpensive in terms of ultra wide angle lenses, the quality of the images is as good as it gets---to see the lens quality be bad I'd need 10 to 20 more years of experience , and with that I could then also circumvent the possible caveats of this thing..

I didn't dare buying a wide angle lens before I was more or less sure I could get something for the price, but having bought this Sigma lens now I sort of hate myself not buying it earlier already!

Very good image quality. Aberration is visible as with any wide lens, but in practical images (i.e. in images not shot at lab with intentions to find aberrations) not easily seen unless looked for. Build is firm, better than most Canon lenses I see. Comes with a hood. Full-time manual focus in addition to AF, which is a big plus.

Nothing at this price; if it cost more than twice it's price, I'd probably say something about aberrations in lab shoots or about my flash not being able to cover the area under 14mm without the extra plate, but then again, those are usually minor problems. And since it's this cheap, I don't cry---aberrations just teach to think better, shoot better.

Nothing as wide as this, as there's not much available.

Excellent. (plus I got this lens mailed to me in one day)

Great lens!

Sharp, excellent build quality, reasonable filter size (77mm).

Can't use flash in camera (Pentax *ist DL).

Using this lens really widens the view for any frustrated APS-C D-SLR user.The width available with this lens is incredible and opens up a whole new world of wide angle photography.
Quality has traditionally been an issue when deciding on OEM lenses or third party but this is one of the better ones that Sigma has produced with good all round performance and relatively low edge distortion for such a wide field of view.
The lens has a good quality, solid feel about it and focuses smoothly on my D200.
A great addition for any APS-C Dslr user.....Must Have!.

Extreme wide angle FOV.
Good if not excellent build quality.
Compact.
Low edge distortion(relative to angle of view).
Low lineal distortion(less than I expected).
Smooth auto focussing.
Cheap price.

Can't really fault this one given it's low cost and good performance.

Nikon 12-24mm Nikkor.
Nikon 18-35mm Nikkor.

None needed-loaner lense.

Dollar for dollar this ultra-wide performs. Weight is not an issue, size is super and it easily replaces one of my Zuiko Lenses in my camera bag. With the 10 - 20mm Zoom I have full coverage with my lens sets to 400mm and all easy to pack up and carry.

$499 is a great price for this lens. Little flare issues, sharp, (obviously not as fast as some, but for the money spent - no issue here). Good thing for this user is that it shares my 77mm filters, used on another lens I carry.

Smooth manual focus, and excellent auto-focus. Zoom is smooth and lens performs well on the Olympus E-3. I have read that some users of ultra-wides experience focus ease - I did not experience anything out of the ordinary in that regard.

Can't say enough good things about B&H. They had it in stock and shipped to me in less than a week from order date.

Used with care and conscious of composition issues with a ultra-wide, the focus and distortion control are incredibly easy to deal with. I was able to get very sharp images in medium to low light hand-held. With a tripod - there is nothing this lens can't do, that the more expensive lenses do.

For a person working on a budget, this lens is the way to go. Thanks to Sigma for working out the bugs on this 4/3rds aspect super wide angle lens.

Putting economics before pride - I am very happy with this lens and recommend it as an alternative to more costly ultra-wides. Money well spent!

HSM Focusing is quiet and blistering fast.
Manual focus is easy to use. User can be confident of a sharp image.
Composition and distortion is easily achieved in camera position to subject. Not a difficult feat.
Personal like: 77mm lens works with my expensive filters. No vignetting noticed in test shots.

None yet. This lens is built to perform, and as a air traveler, my back pack will provide good protection for this lens, kept in my camera bag, inside my roller board backpack. Nothing weak about this economical performer.

I have 2 other SIGMA lenses and they perform well. With all the money I have saved using SIGMA, I can afford to FLY and TRAVEL more often! :-)

Hopefully I will never have to go here. I have used SIGMA products for years, and with good care and not chancing a lens to adverse operating environments - I will hopefully never have to deal with customer service.

Must give B&H one more kudo. These folks are GREAT and the PRINTED CATALOG they sent to my home is a staple "Counter Book" in my kitchen. Everything to make a photographer to drool over. Their approach to business is to keep you as a customer. I am glad that I am and I will go back in the future. Give them a try!