Constant f/2.8, relatively quiet focusing for not having HSM, sturdy and solidly built, good overall sharpness,

Sample variation can be a real annoyance, some distortion at the wide end

The lens was sent in for warranty service twice for focusing problems, primarily back focus. The second trip fixed the problems and I'm happy to have a lens I can count on again. I'm not sure if I will purchase third party lenses again as the quality control just doesn't seem up to par. The time and energy spent troubleshooting the problems and sending it in for service just isn't worth the cost savings in the long run.

Customer Service

Sigma warranty service was fast enough, though it did take two time to fix the problem. The second trip included a politely worded note explaining my frustrations, so maybe that helped.

This is an super sharp, low-light lens great for indoor photography. i photograph sculpture and fine art pieces in museums and I found this to be an excellent choice. also great for weddings, etc, where flash is not allowed but max aperture is needed. i find the usual amount of softness right at 2.8 but stopped down a little, the lens is at max sharpness. beautifully built.

pricey. AF hunts a little in low light.

a sharp wide angle lens with 2.8 capability

sharp
well made
quick focus

slightly soft at f2.8

Have used this lens for a few weeks now and am very impressed. It is tack sharp at all but the widest aperture (still good at f2.8) and focuses quickly and accurately. Very well made and an absolute bargain. 95% performance of pro glass at less than one third of the price!! If you have a full frame dslr then maybe something better would be apropriate but for those of us using aps sized sensors , it ticks all the boxes...get one!

Similar Products Used:

sigma 18-70
nikon 18-70

- F2.8, but if you aren't lucky enough to get a good one, it will be soft at 2.8
- good focal range
- relatively small and easy for- macro, even if it isn't true macro (1:1). It's just 1:3 magnification.
- polarizing filter can be used since focusing doesn't rotate the front element
- the build is pretty good, it feels solid; the zoom ring feel comfortable in using too; the finish gives it a classier look
- even with all the problems I mentioned, at smaller apertures it produced good images; for as long as the subject was in DOF it worked pretty well

- Sigma has bad QC, especially with this model it seems (heard other users complaining about it)
- bad front-focus
- top-right corner very soft
- AF behaves erratically especially in low light, but it might be because the above problems
- AF isn't HSM, thus it's a bit noisier and slower
- Focus ring moves while using AF
- Focus ring has a very small rotation angle, making it impossible to use Manuel focus
- if you want manual focus, you need to switch to it

I bought this lens because I've seen many good reviews and very good pictures taken with it. I also saw some bad reviews, but I thought I can't be that unlucky to get a bad copy.
Well, I was that unlucky. It had bad front-focus, it was extremely soft on the top-right corner too and even from day one I noticed some dust particles inside it.
Fortunately the shop that sold it to me (online shop) is replacing it with a Canon 17-40 L F4 and I am paying the difference. I'm not willing to go over several lenses just to find a good copy, so I'm betting on Canon L glass this time.

All in all, this isn't a lens you want to order online. Be sure you test it before paying for it, or check the return policy of the shop.

Customer Service

Extremely bad service in Romania: there is a dealer but they won't help you unless you bought the lens from them; International Warranty has no meaning here it seems.

Similar Products Used:

Canon 18-55mm F3.5-5.6 (Canon 400D kit lens)

Good auto focus and manual focus relationships to the Evolt camera. 2.8 provides a speedy lens that is less prone to noise or slow shutter speed issues in low light situations. Built like a rock! Sturdy and dependable. A tribute to Sigma's keeping up with the 4/3 format camera needs.

some potential for vignetting with 18mm setting and lens hood. Careful composition can prevent this.

Excellent - fast, perfect zoom range, and quality of image with this zoom lens speaks volumes. Reasonably priced. 18mm-50mm range is a perfect "Default" lens for quick shooting. A super alternative to more pricey Zuiko lenses.

Customer Service

Not necessary - this quality, may never have to return for repair.

- Sharp, razor sharp
- Fast lens
- Good Price

- Slow on Auto focus
- AF motor Noise
- only zooms to 50mm

I promised myself I wouldn't buy anything big at the Camera show, man did I break that one. I was wandering around the show and happened to stop by the Sigma demonstration booth, a couple friends had purchased Sigma products before and both seemed happy about it. Using my Nikon D70s I started trying out lens, and a sales rep came over to me and suggested I try this latest offering that they had. I slapped on the lens and took it over to where a model was standing to give it a shot. Man I couldn't be happier. I walked right over to the Henry's table and bought one.

I have since used it in the two primary fields I shoot in, events, and architecture. It performed admirably in both. If you're looking for a replacement for a kit lens, this is it. It gives you a fast lens (f/2.8) at a price under $1,000. It's a fast sharp lens, plus has good Macro capabilities as well.

Anyone with a dSLR, still using just a kit lens, should get this one to replace it, hands down. (Comes in multiple mounts Canon, Pentax, Sony, Nikon). The money you save can be put towards a 50mm f/1.8.

Customer Service

None required

Similar Products Used:

Nikon Nikkor AF-S DX 18-70mm (Kit)

Sharpness!!! WOW. I can't overstate this enough. This lens is really sharp.
Contrast - nice and punchy.
Ability to open up to f2.8.
Fast focusing.

Focusing noise is slightly louder than the Nikon 18-70.
Distortion at 18mm.

I have the Nikon D70 camera and most frequently use the Nikon 18-70mm lens. While I've been pretty happy with this lens, I've often wondered if there wasn't something a little shaper and a little faster out there in a price range that I could afford. After reading several highly positive reviews of the Sigma 18-50 I decided that this was the lens for me.
To tell you how impressed I am with this lens, after shooting a "test roll" and carefully viewing the pictures in Aperture, I'm putting my 18-70 on Ebay and getting rid of it.
This lens delivers everything it promises. It's incredibly sharp, focuses just as fast as the 18-70, and I'm also amazed at how small the minimum focusing distance is.
Yeah, if you shoot at a brick wall at the 18mm end the distortion is significant, but nothing that can't be fixed with the latest software.

Similar Products Used:

Nikon 18-70mm AFS

-constant f/2.8 aperture is really nice
-sharp
-quick AF
-at 50mm, distortion is very mild

-mild barrel distortion at 18mm
-some vignetting
-fairly quiet, but not HSM

I purchased the Sigma 18-50mm f/2.8 EX DC to go with my Nikon D50. Essentially, the constant f/2.8 aperture is what did it for me. Even Nikon's and Canon's midrange zooms usually have f/3.5-4.5. I wanted f.2.8 for the extra low-light shooting ability and the added depth of field flexibility, and I wanted it without paying $1200 and carrying a lens that weighs in at 3 or 4 lbs. This lens fits the bill pretty well. Overall, performance is good. The AF is not a silent, HSM motor, but for normal focusing the noise is not distracting. It's quick enough unless focusing from macro distances to long distance. When doing that, it takes the lens a bit to go from one end of focus to the other. Overall, though, the AF is fast and doesn't hunt too often. A weekend before buying this lens, I played with my friend's Canon L lenses. (He's a pro wedding shooter.) When I got this lens, I was pretty thrilled to find AF speed close to his lenses. Also, I didn't feel like my lens hunted more than his did in low light. So, yeah, that was encouraging. In terms of sharpness, I'm happy with the lens. Even at wide open f2.8, I find the lens is quite sharp. In the bottom-right corner of my lens, it gets a bit blurry, but in real life shooting, I never notice. It's maybe 1% of the total picture area. As for distortion, there is a bit if you're shooting straight lines along the bottom of the photo, but I use PTLens to solve this quite well. Vignetting is also present when at 18mm at f/2.8, but overall, I haven't found it to be noticeable in normal shooting conditions either. Again, PTLens can help with this when it is a problem. As for chromatic aberations, I was very pleased that this was not an issue at all. I've shot fairly demanding shots in this regard and never seen any fringing. So, in this regard, I'm 100% satisfied.
In re-reading my review, I think I come off a bit too negative. I like this lens. In fact, I really like this lens. It's sharp, has reasonably good AF, isn't too noisy, and has a wonderful constant aperture that can't be found on 1st party lenses for less than $1000. I paid about 1/3 of the price of the Nikon 17-55mm, and I also have a smaller, more convenient lens. Do I wish there was absolutely no vignetting or distortion at 18mm? Sure, but these issues are not really noticeable in 90% of my shooting. So, overall, and especially for the money, I really like this lens.

Customer Service

-haven't needed it yet

Similar Products Used:

-wide range of Canon lenses, but not extensively, so not much.

- build quality - constant aperture - price - size

- narrow depth of field (?) - front of lens element does not rotate during focus, but a section in the centre does. Slightly annoying if your hand happens to be in the way

I plunged for this because I wanted constant aperture throughout the zoom range, faster speed, and the extra 10mm over the Canon 17-40L. And of course, the price. I'm very impressed by the lens. Seriously sharp. I've sort of experienced focusing "problem" mentioned by many reviewers - but I'm not sure if it's really the camera instead of the lens. It crops up when one is trying to focus on really thin foreground/background objects, so my guess is perhaps the actual autofocus point selected by the camera was wrong - and that is because the user is not aiming perfectly. In any case, simply using manual focus solves everything. However, one possible "problem" is that depth of field tends to be quite short especially in low light, so if you didn't focus on the right thing, the result could go very wrong - but that's par for the course for any lens. Build quality is great and solid - material feels like magnesium alloy but I'm not really sure. Also, it's not too big (an inch longer at widest than the 18-55mm kit lens on the 350D at full tele) and not too heavy.

Razor sharp! Equals the Canon 17-40f/4L. Great color rendering, fast autofocus, size and weight.. Friendly price.

At 17mm: some corner softness at low apertures and some chromatic abberations.

This week I have learnt that buying lensen (even more than camera bodies) is all about emotion and presumptions. I got myself this nice Canon Eos 20D with the Canon 17-85 f/4 e-fs as kit lens. To cut a long story short, that lens turned out to be a lemon, so back to the store, a bit disappointed. I was strongly thinking of trading it for a Canon 17-40 f/4L. A beautifull performing lens that I had owned before and sold, probably in a state of severe mental illness. But... Canon high-end glass is -apart from expensive- always in short supply in Holland and impatienly as I am I was forced to look for an alternative. I did my research and came up with this Sigma 18-50. Every review I've read was good to great and I have to thank previous reviewer Twoblink for providing links to several test sites. So on my way to the store to trade the Canon for the Sigma. This is where the psychology part started. I must have shot hundereds of pictures under a variety of conditions and apertures and most turned out excellent. So rationally I knew that I had made a good purchase. But emotionally I kept lingering for the 17-40. I have spent hours and hours scrutinizing the Sigma pics, just to find a serious flaw what would justify the purchase of the Canon 17-40 after all. Canon is a major, established brand name; their lenses are expensive so THEY HAVE TO BE THE BEST OF THE BEST. Or aren't they? On a subcontious level we have all learnt the equation: "reputable brand name+high prices=topshelf product". It took me half a week to come off this wrong mindset. The truth is that the Canon 17-40f/4L indeed does make great pictures. But the Sigma 18-50 DC f/2,8 EX also but for a substantial lower price tag. During my scrutinizing hours I have compared tenths of old pictures, taken with my 17-40 and guess what? Even the Canon appeared to have some corner softness at 17 mm and isn't totally free of chromatic abberations also. The funny part is that I had never noticed that before, because when I bought that lens I automatically assumed that it had to be a winner since it was an L-serie from Canon. Now I realize that I have never tested that lens the way as I have tested the Sigma. So... I'm very happy with my Sigma and I can honestly say that picture quality is on par with the canon 17-40. Because of the 2,8 and the 10mm extra at the long end I rate the Sigma even higher. I haven't encountered any problems so far. Autofocus is fast and spot-on, color rendering neutral and contrast is good. Sharpness is just excellent. Highly recommended! Feel free to check out my portfolio at http://www.usefilm.com/MyPortfolio.asp?id=33691 The pics taken with the 20D are taken with the Sigma.

Customer Service

Not needed.

Similar Products Used:

Canon 17-40f/4L, Canon70-200f/4L, Canon 90-300 usm, Canon 18-55 ef-s, Canon 17-85 ef-s and a lot of Nikon lenses when I shot film.