None. I'm vexed that I'm not allowed to award this worthless piece of junk "Zero Stars"

Can't focus.

This lens simply couldn't focus correctly. Front-focus, back-focus, misfocus. Anything but the actual focus target might be sharp. What else is there to say? Without accurate, consistent, correct focus any blabbering about build quality, or optics, or anything else is just so much hot air. Oh, and Sigma wouldn't/couldn't fix it, either. "It must be your camera," was their tiresome refrain. Forget that I tested it on five (5) bodies. Forget that I've got two dozen other lenses that work just fine. "It must be your camera." Nah. It's not my camera. It's this worthless chunk of glass & plastic.

Customer Service

Disaster. Sold product and resolved never to do business with Sigma again.

*Like a Canon 17-40L/4 or Nikon 17-55/2.8 for about 1/3rd the price *As sharp as a prime stopped down *Very usable range, 27~75mm on Nikon DX. *Center is very sharp *Light and Compact *Affordable *Zoom is smooth and fairly well damped *Zoom grip is well ribbed for easy grip

*Focus Ring Moves *Heavy Vignetting at F2.8 @ 18mm *Filter size kind of in the middle *APS use only *Soft corners until past F4 *Would like a little bit longer on the long end.. 18~60mm would be perfect, that would get you the 90mm "portrait" perspective on the long end, 75mm is a little bit wide. *CA prevalent at F2.8 *The EX surface coating gets dirty easily

There are Cannonites who will poopoo all over this review, as well as Nikonians. But what remains to be a fact, is that this is one of the sharpest lenses available for the APS size sensor REGARDLESS OF BRAND OR PRICE. Up against 50mm primes, this lens holds its own without a problem. Up against Uber-zooms from OEM's, it holds its own and even surpasses some. I'll make this review short and sweet. The focusing isn't that fast, the construction isn't vault like, and it's noisy when it focuses. All the money was spent ON THE LENS, where it should be. I have pitted this lens against other zooms, and it performs better than the Canon 17-40mmL, and is on par with the Nikon 17-55mmF2.8. That's all that needs to be said. It's smaller, lighter, and faster than the Canon 17-40mm at almost half the price, and it's smaller, lighter, and images are just as sharp as the Nikon 17-55mmF2.8 at 1/3rd the price. I find vignetting and CA to be too much at F2.8, and so I shoot at > F4 most of the time. So I treat this lens like an F4 lens, with a usable F2.8 if things get bad. Highly recommended, if you are considering the kit lenses, try this instead, the F2.8 gives a brighter viewfinder, and it beats the pants off both the Canon and Nikon kit lens. If you are going to take this lens to the Amazon or the Safari, then I recommend other lenses, but if you aren't a pro and won't lug it into jungles and mudsling it, then this is the perfect lens. I've shot a few weddings, and all of them with just one lens: This one. The images are sharp, the focus is dead on, and the customers are overly happy with the results. Coupled with good technique, this lens will do you proud. This lens beats the Canon 17-40L and the 24-70L. Don't take my word for it, read it for yourself. http://www.photozone.de/8Reviews/lenses/canon_1740_4/index.htm http://www.photozone.de/8Reviews/lenses/sigma_1850_28/index.htm http://www.photozone.de/8Reviews/lenses/canon_2470_28/index.htm http://www.jasonlivingston.com/sigma-review/ Another comparison of the Canon 17-40L vs the Sigma 18-50. They also throw a 50mm F1.4 prime in there, so you can see how the Sigma stacks up against the prime. http://www.ephotozine.com/equipment/tests/testdetail.cfm?test_id=342 From this article, quote: "Sharpest lens tested to date" 'nuff said!!

Customer Service

Haven't needed it.

Similar Products Used:

Nikkor 17-55mmF2.8 Nikkor 50mmF1.8 18-70mm f/3.5-4.5G Canon 17-40mmF4L Canon 50mmF1.8 Zuiko 50mm F1.8

Best performance and size of any zoom that I am aware of. It has the convenience of a small, light zoom, yet has F2.8 and good image quality for a zoom.

It's a zoom so its image quality will not be as good as a prime, but it's good by zoom standards. Auto-Focus speed and manual focus would be excellent with an HSM focus, but its good as is.

I am a professional with 15 years of 35mm film experience. However, I'm new to digital photography. I photograph people (mostly indoor parties) and I do real estate photography, which is architectural photos both indoors and outdoors. Some of the portraits and groups are with subject cooperation. Many are candid. Flash is not allowed at these parties. Tripods are allowed, but discouraged. So I am dealing with (on 35mm film) wide angle 24mm, 28mm, and 35mm lenses on up to 50mm normal lens. I have always preferred prime lenses because they give sharper images than zooms, however the best zooms are getting good now, especially zooms with a small zoom range made for DC. I'm building a set of primes from super wide to normal, taking into account the conversion factor for digital cameras. I've pretty much decided that I prefer Sigma's lense products over Canon's. I want to get Sigma's 14MM, 20mm, 24mm, and 28mm primes and a good zoom. However, I ran across both Sigma's 30mm F1.4 and 18-50 F2.8 lenses and am very impressed and intrigued. I realize that I am new to digital, but my 15 years experience with optics does apply. I often see people trying to compare the sharpness of a zoom to a prime. That isn't fair. Primes are almost always sharper. Besides primes being sharper, they are better for low light photos because they let more light through. This is why I will always need a bag of primes. My next bag of primes will all be Sigma, except in lengths they don't make, which will be Canon. However primes are inconvenient to carry a collection of. It is often inconvient to change primes. Changing prime lenses at a wedding can lead to a heart attack for me, which is why I stopped doing weddings. Sometimes I don't mind carrying a gym bag full of primes, but other times I'd gladly trade some sharpness and image quality for a high-end zoom that would give at least decent image quality and be handy and light. That is the point: You only have the right to expect "decent" image quality from a high-end zoom lens. If you can get better than "decent" image quality from a zoom, then you should be screaming with pleasure because that is as good as it gets for a zoom. The really nice thing about a zoom is convenience. However, zooms tend to be slow (dark), unless you get a high end F2.8, in which case they are very large and heavy. This 18-50 F2.8 Sigma is really amazing because it offers decent or better image quality, is FAST at F2.8, yet is also small and light. Wow! That's the best zoom lens I ever heard of and it doesn't even cost much. I am really impressed by this Sigma 18-50 F2.8 lens. It's amazing. It will be the third zoom I've ever owned. I sold the first two because their image quality was too inferior compared to my primes. This time, I have more reasonable expectations and will also be getting the better Sigma lens. My expectations are now reasonable because I no longer expect the impossible. I know the zoom will not be as sharp or as fast as primes. That's why they still make primes. But I do delight in knowing it will give decent sharpness in situations where there is enough light to stop down to F4 or 5.6. I will also delight in the small size. I think this must be the smallest F2.8 zoom ever made. So don't anyone compare the sharpness of this zoom lens to primes. That ridiculous. Compare it to other zooms. Especially compare it to other F2.8 zooms of similar zoom range so you get an apples to apples comparison. Some vignetting is to be expected on any lens more wide than 24mm, especially if it's a Fast F-stop lens being used wide open. This is even true of primes such as an 18mm or 20mm prime. So I think a little vignetting for this zoom at 18mm is to be expected. An 18mm or 20mm prime would vignet too. Lastly, I hear many people say the fact that this lens only works on digital cameras is a weakness. It is not a weakness. It is simply a fact of life that results in advantages. The fact that it is made for DC is why this lens can be 25% smaller and lighter and still be an F2.8. Lenses made specifically for 1.5 digital are 25% smaller and lighter when made with the same max F-stop as the same focal length (or zoom range) lens made for film. Another awesome lens, especially for low light, is the Sigma 30mm F1.4. It is smaller and lighter than Sigma's 28mm F1.8. Here the DC lens design advantage is used to gain approx 84% more light and reduce size and weight by 14%. Being designed for DC is also an advantage for image quality as everyone else has already mentioned in detail. Being a DC lens is an extreme stength, not a disadvantage. I hear some of the SAME people who praise the small size and weight and love the fast F2.8 say that they wish it had a larger zoom range. Get real people. If you increase the zoom range, the image quality and lens size-weight will all suffer. You can't have your cake and eat it too. You have to make up your mind what attributes are most important and go for those. You can't have everything in one lens. However, this lens comes the closest to giving everything that I've ever seen and it doesn't cost much. This is as good as it gets for a zoom. If you don't like this zoom, then use primes. I intend to use both. People need to have reasonable expectations from equipment. If you want max image quality, use prime lenses. If you want convenience use a zoom. If you want the best compromise of both, then use this 18-50 F2.8 Sigma zoom lens because this is the best there has ever been and it doesn't that cost much. Likewise, people need to have reasonable expectations for extreme wide angle lenses. Wide angle photography has been my specialty for 15 years. If you want to go more wide than 24mm, you will see some vignetting, especially at wider aperatures. This is true even on the best prime lenses in the world. So how can you expect a super wide zoom not to have some vignetting? A super wide zoom will have some vignetting, especially at wide aperatures. This is a fact of life. The real question is not if it's going to be there, but how bad is it and how does it compare to the same focal length prime or zoom? It looks like Sigma did a good job of keeping vignetting to a minimum at 18mm, considering that this is super wide. If you can't deal with a little vignetting, then stay at 24mm or higher, better still stay at 28mm or higher. i.e. - you have to expect some vignetting heat in the super wide angle kitchen. If you can't stand the vignetting, then stay out of the super wide angle kitchen. Same with distortion. You have to expect some in wide angle, especially below 24mm. The real issue is not if it's there, but how bad is it? If it compares favorably to other wide angles of similar focal length, then don't worry about it. Try to work around it when lining up your shots by keeping as perpendicular to straight lines as possible. Then ignore what remains of distortion. i.e. - do what you can in composition and then don't worry about it after that. Always compare zooms to zooms, primes to primes. Don't expect perfect image quality from a zoom and don't expect convenience from a prime. Overall, this Sigma 18-50mm F2.8 is the best zoom for the money and likely the best period. It's image quality is excellent FOR A ZOOM, which would be considered "decent" compared to a bag full of primes. Have reasonable expectations and appreciate this lens for what it is: Compact convenience with decent image quality. That's all you can ask for from a zoom. I don't want to offend anyone here, but I just want to give a reality check on lens expectations. The Sigma 18-50 F2.8 is as good as it gets for a zoom, in my opinion.

Similar Products Used:

Every prime Minolta MD and Pentax lens ever made from 50mm down to 20mm. Sigma 14mm and various high-end F2.8 Tokina zooms. The Tokina's were good for zooms, but can't compare to this Sigma 18-50 F2.8.

Quick focus, little focus "wander", good build quality, included sunshade and case, relatively light weight and small size

Works only with APS-C image sensors, a little soft at F2.8

Image stabilization is the new hotness in lens design, but being an old-fashioned sort, I went on a search for a lens with a wide maximum aperture instead. Sure, IS and VR give you the ability to hand-hold week long exposures, but what if your subject is moving? Amazing what a difference that extra stop can make when you need to capture action in low light. Plus, the AF system works better, and the viewfinder is brighter. Cost, however, is what drove me to this lens. Due to financial constraints, I could afford no more than $500 for a lens for my 300D, which knocked the Canon L-series glass out of contention. After looking at the Tokina and Sigma 28-70 F2.8 lenses, I discovered this lens was in the pipeline and held out for it. It's not a replacement for the Canon L-Series lenses. That's the bad news. The good news is that this is possibly the PERFECT advanced amatuer lens. Good optical quality, though a little soft at F2.8. Focuses quickly, and "wanders" less than other EF-mount lenses I own (18-55mm EF-S kit lens; low-end Sigma 28-90). The wide aperture allows for auto focusing in what feel like "no light" situations.

Customer Service

Not used

Similar Products Used:

Canon EF-S 18-55mm (non-USM)

Excellent Build and Finish Sharpness Pleasing Bokeh Fast 1:2.8 Aperture Internaly Focused

No DOF Chart Focusing Ring feels a tad too loose, but better than many AF lenses Zoom ring only locks at 18mm

After much debate between this lens and a Pentax FA-J 16-45mm f/4 I finally settled on the Sigma for it's f/2.8 aperture, and I'm pleased with this decision. This is a top quality lens. The construction is solid. It's an EX lens so it doesn't feel like the lower-end Sigma lenses. The only "plastiky" part you'll find on this lens is the lens caps. It has a tab to lock the zoom ring, but it only locks at 18mm. A nice idea, but it should be able to lock at any focal length. It's an internally focused lens, so the lens doesn't change size as it focuses and the front of the lens doesn't rotate so it makes using a polarizer simple. Unfortunately it has 67mm threading, and polarizers of this size is a tad pricey. It's a sharp lens, even at f/2.8. Stop down to f/5.6-f/11 and it gets really nice. Bokeh is also pleasant and smooth. A downside is some slight viginetting at 18mm.

Similar Products Used:

Sigma 28-80mm f/3.5-5.6

sharp at all zoom range, extremely sharp and details at F3.5-F5.6 Light, good for travellers F2.8 enable to shoot at low light Fast Autofocus Can be use as portrait lens @50mm.

some chromatic abberration wide open autofocus make a little noise only for APS-C size DSLR. Not for flim.

Lens is light, zoom ring not as smooth compare to my tokina. Well, i don't really care about appearance anyway. Output quality is top, sharp at all zoom range, specially F3.5 to F5.6. manual focus ring is wide and easy to control. Good as travel lens, i always use to shoot portrait, bokeh is pleasant.

Similar Products Used:

sigma 18-125mm tamron 17-35mm

Light, sturdy, sharp, fun. A GREAT walk-around lens. Uniquely useful focal range. Fast focus (even in the dark, despite other reviews to the contrary). Feels well-balanced on a 20D body with battery grip, despite being very light.

None that are not really picky.

This lens is something of a surprise: surprisingly light, compact, sturdy, sharp and surprisingly fun! I did not think there would be a bargain bang-for-the-buck lens like the Tamron 28-75/2.8 XR Di made for quite some time--but this Sigma beats the Tamron for price/quality. It has the "pop" of the Canon 17-40/4L while being lighter, adding a usable 2.8, and adding another 10mm at the long end. I have wanted to be able to cover the focal length I most often use with just two quality lenses. With this lens and the Sigma 70-200/2.8 EX HSM I can do just that. With a 24-70 (much less a 28-70) I always felt I needed to add a wide zoom or at least a wide prime. Not now! The 50mm end of the 18-50 and the 70mm end of the 70-200 are both very usable for candids and portraits. And for anything in between I guess doing a little "foot zooming" is worth it for the ease of carrying only two lenses. After buying and selling and enjoying some fine lenses in the Canon L and Tamron camps (zooms and primes) I have finally ended up with a bag that is filled with only two Sigma lenses. And I don't feel a bit deprived.

Customer Service

No experience yet.

Similar Products Used:

Tamron 28-75/2.8 XR Di, Canon 24-70/2.8L, Sigma 70-200/2.8 EX HSM.

1 excellent image quality from f4 and tops at 5.6 up. 2. quite an idea range for DSLRs 3. very light for a 2.8 zoom 4. well built although not as the nikon one 17-55 5. feels very comfortable on the D70 6. quite a fast focusing considering itsnot hsm -thats a pitty though

1. some bareeldist at 18-22 so be carefull with strait lines for achitecturals 3. a little warm but eailly corrected with levels

I've used mainly nikon in the past but when I thought that sigma came out with a " winner " lens I went for it . I think this lens is one of them . The other excellent lenses I used in the past were the 12-24 ,70-200 and 105/2.8 macro . This is an amazingly light very ergonomicly designed , fast focsuing lens , though not as fast as the 12-24 hsm , for example . I tried 2 lenses. The first one was a little soft on the right hand side at 2.8 to 4 but got very sharp at 5.6 . The one I bought is sharp even at 2.8 but gets very sharp at f4, edge to edge and maybe extremely sharp at 5.6 up , the images are so clear and contrastive they have a punchy feel. The images tend to warmer than nikons- thats typical of all sigmas I have used but then, it is easilly solved in levels or curves in PS . At 18mm there is some barrel dist . but with my sample , you see it only on the left side . this disappears at about 22mm up . I actually prefer its image quality to the 50/1.8 but Im keeping the prime for low light conditions,that is from 2.2 to around F4. This lens covers the range I use probably 80 % of the time , I would have liked it to go to 17 although the extra 5mm as offered by nikon 17-55 is not such an issue . At this price I think this is a trully a great lens.

Similar Products Used:

nikiors 50/1.8, 80-200ED

You have a f/2.8 usable lens It is lightweight It does not cost a fortune Well build Fast focus

A little vigheting at 18mm f/2.8(not a really problem) Not compatible with full frame format

I bought this lens because I wanted a resonable priced f/2.8 lens.I am very pleased so far with the lens.I haven't noticed any front or back focusing as some others did.It is a very good alternative if you do not have the $$$$ for a f/2.8 Canon lens.The lens is usable at f/2.8 and excellent at f/4+.I have noticed a bit of vigheting at 18mm at f/2.8 but nothing big.It is well build and it has a fast focus motor.It is a click slower than USM,HSM but is ok for me.

Similar Products Used:

Canon 17-40L(good but more expensive and f/4)

Sharp images, Fast autofocus, Accurate autofocus, Light weight, A good focal range for Digital SLR

No manual focus override, you have to flip the manual focus switch. HSM would be nice.

Overall a very good lens for my EOS 20D. My first impression was that is was too light. It must be a lousy build. But it is solid. The zoom isn't real smooth and the manual focus is a little too easy. But the auto focus is accurate. It comes with a lock for zoom creep. But there isn't any zoom creep. It is SHARP from 18mm to 50mm Very sharp, good contrast and rich color images. Slightly soft at 2.8 but not bad.No HSM but the focus is fast and not very noisy.

Customer Service

N/A

Similar Products Used:

Sigma 70-200mm f/2.8 EX APO HSM SIgma 24-135mm f/2.8-4 Sigma 17-35mm EX DG HSM