• Solid build quality & finish, surprisingly good focus speed and accuracy.
• Overall pretty decent optical performance, except at the very long end (in my sample).
• Pretty unobtrusive internal focus, no rotating front-end. You can use petal shaped lens hoods, polarizers and grad filters without problems.
• Quite heavy, especially compared to the D40’s (very good) 18-55 mm. AF-S plastic kit-lens. But, compact enough to be well balanced and not overly heavy - it is the lightest among its peers; you can use it hand-held and without penalty down to 1/125 or even 1/60 sec..
• Very flare resistant. I have not seen any in my 4.000 takes with this lens, sofar.
• Well placed AF-MF switch, useful creep-lock button for transport.

• Chromatic aberration and purple fringing on highlight edges throughout the focal range, especially wide open. This can, however, be easily corrected in post or even in-camera (select Nikon models).
• Pronounced barrel distortions at the wide end, some pin cushion in the medium to long focal ranges.
• No built-in image stabilization. Users who are prepared to pay for an expected 1-2 stop gain, might want to consider the optically stabilized OS-version. (MSRP: $ 750)
Combined with one of the clean high ISO Nikons, however, one ought to very carefully balance his options. You can get as much as 3 stops (ISO 1.600) from these cameras with minimal sacrifice, while 300 bucks extra is 300 bucks you can spend elsewhere.
• Can *not* be used with the Sigma EX 1.4x and 2x tele-converters. But then, I would not recommend using a lens of this level with a TC, anyway.
• The f/max. of f/6.3 at the long end is pushing towards the very extremes of AF capability; the lens may hunt on occasion, but only at the long end.
• Not exactly cheap for a "consumer" or kit lens.

Conclusion*:
Optical quality: 3,5
Build quality: 4
Design: 5 (no mayor flaws)
Value for money: 3,5

* 1 = poor, 5 = excellent

Recommended (for social events, weddings, light travel, pseudo P&S)

For starters, anybody who expects stellar optical performance from a 11,1 zoom, better stop reading right now. It is not going to happen, not with this one, nor with the Nikkor.
I got this lens in a hurry, because I needed an all-purpose lens to cover a spur-of-the-moment client event. At the time, this was the only 18-200 mm. available in Santiago.
I also took a look at the (now discontinued) 18-125 mm. f/3.5-5.6D Sigma, but decided against it because it lacked the built-in focus motor necessary on the Nikon D40, my target camera.

Tamron offers a similar lens, and so does Nikon: the AF-S DX VR Zoom-NIKKOR 18-200mm f/3.5-5.6G IF-ED comes with optical stabilization (VR in Nikon speak) and a built-in Silent Wave Motor (the S in AF-S), which presently streets for about $ 700 at Amazon.

I expected this Sigma to focus slow compared to my HSM and AF-S lenses, but it’s surprisingly fast on the D40, the only camera I’m using it on.
Build quality is also unexpectedly good, with a metal (instead of plastic) F-Mount, a partially metal body and a nice - EX type - crinkle finish.

The AF/MF switch is placed where I need it to be, and the lens also includes an anti-creep button that locks it in the 18 mm. position for trouble-free transport.
Thanks to internal focus (IF) the front end does not rotate, facilitating the use of a petal-shaped lens hood (included), polarizers and other orientation sensitive filters such as grads; however, it extends considerably - making it look a bit “amateur” at the long focal end.

At 18 mm., this lens suffers from pronounced barrel distortion and vignetting (wide open), but produces very good to excellent center sharpness, combined with good sharpness at the extremes.
At 35 - 85 mm., the center is still very good, but the borders suffer at large (if you can call f/5.6-6.3 "large") apertures.
However, stop down just a little, and border quality reaches again very respectable levels.
From 100 mm. on, the lens is pretty good stopped down to f/8, but interestingly, testers found that resolution (MTF) starts dropping off as soon as f/11.
You’d want to be extremely carefull with your aperture selection to get optimal results.

I have found myself avoiding the 200 mm. end, where my sample is decidedly soft, even stopped down. Lay off a little, though – to 150-180 mm. – and the problem is gone.
Because of it’s rather complicated optical construction, this lens suffers (as expected) from moderate chromatic aberration throughout it’s focal range.
On the other hand, it’s not as bad as other, even more expensive, lenses of comparable focal range.
In short, pretty decent for a budget 11,1 times zoom, which seems to reach its sweet-spot early on: only 1 to 1,5 stops down from its f/max. throughout the entire focal range.

People who have been destroying this lens (and others like it) in their critiques, seem to forget that for some purposes - like social events, weddings and general light travel - an all-purpose 11x 400-dollar-zoom-lens comes in extremely handy, and therefore, ought to be forgiven for some of its weaker points.
Lest of course, you are prepared to lose *the* shot while changing lenses back and forth (which I am not) or are planning to mount it on a 8.000 dollar D3x, which is plain out stupid.
Lets face it, this Sigma makes for a fairly campact & light package, which, combined with any half decent DSLR blows the pants (plus underwear) off of any 10x zoom P&S camera out there.

Customer Service

None needed.

Similar Products Used:

Nikon CP 5700 - 10x Zoom P&S

Small size - Large Zoom Range
Zoom Lock
Hood included

Slow noisy AF
Serious vignetting
Only acceptable sharpness
Poor exterior finish

I bought this lens originally for my Rebel XT to replace the Canon 28-135 IS That I found did not offer enough wide angle with the 1.6 crop. While I was happy to get some wide angles I have grown to dislike this lens. First this has been the walk around lens for the Rebel XT and then in the last 8 months the wife's XTi. It's biggest issue is it shows serious vignetting. EVERY PICTURE with a light or sky background needs to be edited in Camera RAW to correct this. I would replace it but the large zoom range that it provides means that the wife can carry it in a small lowepro bag and not swap lenses, a task she hates. The finishing material has recently started to rub off. I would not buy this lens again. Canons EF-S 17-85 is a much faster focusing, quieter lens with IS for not too much more(in DSLR terms). It also has less vinetting. Heck, I think the kit lens may be a better option.

Customer Service

Never used

Similar Products Used:

Canon EF-S 18-55
Canon EF 28-135 IS
Canon EF-S 17-85 IS
Canon 100-400 L
Tamron EF 70-300
Canon 50mm 1.8

Produces clear bright images, with faster more accurate focusing than the Tamron. (Price).

This lens has less weaknesses than any other lens in it's price range.

Some barrel distortion, and corner softness. It can have a hard time focusing in low light.

I've used two 18-200mm lenses on my Nikon D50. The first lens I used was the Tamron. It had to much distortion, and softness for my taste.

The Sigma's 18-200mm produces sharp clear center images, with faster more accurate focusing times, (compared to the Tamron), with less center distortion. However the lens does produce some barrel distortion and corner softness.

Remember this is not a high end lens, but for the money I think it is a very good lens for me, and it's intended market.

Similar Products Used:

Tamron 18-200mm Di II LD Aspherical.

Light, easy to walk around with.

autofocus has problems with little light situations

The Lens is okay, but I don't know if it's a coincidence or not. Because I live in a dusty country it's annoying. Once the lens is on my camera, I believe somehow a lot of dust gets on the sensor, much more than other lenses. My Canon10-22ef lens was mounted for sevral weeks and I had no dust problems.


Does any one have the same problem?

Sharp lens
Lighweight balances great with the small XT body
Compact design
Lens hood is included
Nice finish to out side of barrel

No image stabilizer but at this price none have it so zooming in faint light makes tripods mandatory.
Non USM AF so you can't overwrite on the fly w/o switching to MF

This is a great lens for people with small SLR bodies that take thier gear into high and remote locations. I use a Hoya UV filter and the included Hood carried in a Pelican 1300 or LowePro 65 AW topload. It takes sharp pictures and 11X zoom so going from wide angle to telephone is a breeze. This is my primary lens.

Customer Service

No needed

Similar Products Used:

Tamron 18-200
Canon 28-135

Highly acceptable image quality. Wonderfully broad zoom range. Quite a deal for the money.

Slow, slow, slow. It’s a sunny day lens, especially at the long end.

I bought this lens because of the positive reviews I read of it here, and I have not been disappointed. I have for my Canon 20-D Canon’s EF 24-70mm f2.8 L and 70-200 f4 L USM lenses. These are indisputably better lenses, but they are also bigger, heavier, and it takes two of them to cover not quite the same zoom range. The image quality from the Sigma is plenty good enough and it is improved with post-processing. The Sigma lens is small, light and unobtrusive, all important qualities for the street photography I like to do; it has an awesomely broad range and it doesn’t draw attention to itself. These are all attributes for which I am willing to compromise.
The lens seems well made. It doesn’t rattle like Canon’s EF-S 17-85mm f4-5.6 IS lens. The auto-focus is swift and, in my experience, sure. Benjikan, who reviewed this lens here (02/16/2006), pinpointed very well its weaknesses along with the remedies for those weaknesses.
One thing, though, this lens is dog-slow. I live in the Pacific Northwest, where late spring tends to be gloomy, overcast and dark for days on end. I had to wait a week after I got the lens for the sun to come out so I could really give it a workout. Under dark skies it was just a rather slow 18-80mm lens. Otherwise I was looking at a 30th of a second at f6.3. Once the sun came out I have filled a 1 gig card with images and have been well pleased with them all. There are limitations with this lens, but within those limitations it performs very well, and it is a great value for the price.

Customer Service

none needed

Similar Products Used:

Canon EF 24-70mm f2.8 L USM
Canon EF 70-200 f4 L USM
Canon EF-S 17-85mm f4-5.6 IS USM

Compact. Cheap. Sharpness.

Soft edge when wide open at 18mm.

Incredibly sharp. Handy as a all-rounder lens. A little bit soft at the edge in 18mm but acceptable. Compared with Tamron 18-200 and went for Sigma after checking pictures.

Customer Service

N/A.

Light yet good optical quality

None so far.

I must say that this is a very good looking and performance lens compared to EF28-105 f3.5-5.6 lens or other EF lenses. I wish I could use it with EOS Elan 7NE so that design of the body and lens mactches well.

As for the optical quality, I am happy that I have traded-in my beloved EF28-135 IS USM lens. This is more versatile (lighter) and more useful (wider and longer zoom) while it performs better in most cases than the IS lens.

I was worried about the performance of wide-to-zoom lens since I have had a bitter experience with Tamron 28-200mm lens. But this is the lens I carry around when I want to bring my EOS 10D with me.

Similar Products Used:

EF28-105mm USM
EF28-135 ISmm USM

Price, Long focal-length range, okay fast focusing, Sharp at some focal lengths, acceptable focus noises

Nothing significant.

I would say this is the perfect walk-around lens, VERY compact with a Stupidly good zoom range. This isnt exactly light but isnt at all heavy so its pretty much perfect. The sharpness at 18-125mm is close to the Sigma Macro 50mm DG but the colour constrast is not as great as an EX. The Lens does get softer when approching 200mm quite drasticly compared to around 70mm where its at its best. at 18mm there is mild barrow distortion but nothing compared to other 18mm's around. Focus is fine, Very fast for its type but still inferior to a USM or HSM. Its CHEAP, very cheap for its quality at around $400. The Min focus at 45cm isnt exactly long but it makes this lens pretty much useless for macro thats why the 50mm Sigma EX is a cheap alternative for anyone that needs a macro. The build is well made, dosnt feel anything as cheap as the 18-55mm thing that comes with the Canon DSLR kits nowadays. The only problem is that zoom is too smooth and that while on your neck the weight of the front causes the lens to fully extend but with the "lock" function on the lens its perfect but does take some time to get used to. A must have for all beginners but please dont even dream of comparing this to any short of professional grade lens :). The aperture is larger then i want....but its way into the acceptable catagory. The lens has low flare generally but becareful what kind of UV filter you choose to use, it has virtually no flare with a multicoated filter but a normal cheap filter will give you flare hell everytime it gets near a lightsource but that has nothing to do with the lens. It has little vignetting when it comes to 18mm but nothing that would visible unless the gradients/curves/contrasts have been enhanced in photoshop during post processing.

Similar Products Used:

Canon 70-200mm f/4L, Canon 18-55mm (wouldnt really call this a lens), Canon 35-80mm II, Nikon 18-70mm (nice kit lens), Nikon 35-105 f3.5-4.5. Canon 70-300mm USM.

great price and value
awesome pics

noisy. not too much but becomes noticable in polite company

awesome lens.. yes htnaks everyone for the great reviews and yes all oof you are rigth.
great noisy lenses for the price that you cant beat,
well thats that and i have no otehr lenses to compare with but all i can say is that there are no complaints and so far pic after pic is turning out beautiful.
great going everyone and thanks for all the advice

Customer Service

great from sigmafor less.com... theyre good guys..... honest and fast

Similar Products Used:

none