Description:

Sigma 18-250mm long-range zoom lens for Canon, Nikon, Pentax, Sigma and Sony
DSLR cameras. Designed for
APS-C and
DX sensor based cameras, the lens compensates for
image shake by combining the camera's built-in anti-shake with its own optical stabilizer. The lens also boasts four
Special Low Dispersion glass elements and three
aspherical elements to reduce
flare and ghosting.
Internal focusing means the front element doesn't rotate so polarizing filters can be used.

Sigma 18-250mm f/3.5-6.3 DC OS HSM Lens Top Angle View
If you need a low light lens, this isn't it. If your primary objective is to take pictures in low light situation such as
weddings and
concerts,
in the 18-200mm range you need 2 lenses, get the 18-50mm f/2.8 Sigma or Tamron
17-50 VC and a 70-200mm f/2.8 lens instead.
HSM means this lens will autofocus on Nikon D40/D40x,
Nikon D60, Nikon D3000,
Nikon D3100 and the
Nikon D5000 DX Cameras

Sigma 18-250mm f/3.5-6.3 DC OS HSM Lens Zoom View
Superzoom
The term hyperzoom or superzoom is used to promote photographic zoom lenses with unconventionally large focal length factors, typically more than 4× and ranging up to 15×, e.g., 35 mm to 350 mm. The largest ratio for digital SLR cameras is held by the Tamron 18–270 mm, giving 15×. Some Digital Camera Review by Gene Wrights have even larger zoom ratios up to 35×. For movie and television use, Panavision holds the record with their 300X HD Lens.

Sigma 18-250mm f/3.5-6.3 DC OS HSM Lens Top View
While superzoom lenses have improved greatly in recent years, they still have a number of drawbacks in comparison with shorter-range zooms and prime lenses. Most notable is the much increased likelihood of significant distortions of the image at both extreme ends of the range. Other potential problems include smaller maximum aperture and poorer autofocus performance
Following is a list of superzoom lenses, used for 135 format in SLRs or for APS format in DSLRs. The minimal factor used here is 5×
or more. A 28–200 mm has a 75° to 12.3° angle of view, a 28–300 mm (or an 18–200 mm for an APS DSLR) has
an 11.1x 75° to 8.2°
Features
The Sigma Corporation announced the launch of new SIGMA 18-250mm F3.5-6.3 DC OS HSM on March 10th, 2009.
The SIGMA 18-250mm F3.5-6.3 DC OS HSM incorporates
Sigma’s original anti-shake compensation function, with a 13.8 times zoom ratio. As opposed to having an anti-shake function in the camera body, this lens’s Hybrid Optical Stabilizer provides not only an anti-shake function for the camera body, but also compensates for image shaking in the view finder as the Optical Stabilizer is built in to the lens.
Incorporating four Special Low Dispersion glass elements and three aspherical lens elements provides excellent image quality throughout the entire zoom range.
This lens has a minimum focusing distance of 45cm (17.7 inches) at all focal lengths and a maximum magnification of 1: 3.4 reproduction ratio, making it ideal for close-up photography. An inner focusing system eliminates front lens rotation, making it suitable for use with
circular polarizing filters and the supplied petal-type hood. Incorporating super multi layer coating reduce the ghost in the backlight photography.
Compare this lens to the Nikon 18-200mm,
Sigma 18-200mm,
Tamron 18-250mm, Tamron 18-270mm and
the Tokina 16.5-135mm Lenses
Item Includes
Petal-type Hood (LH780-04) - Sigma Warranty
Reviews
Sigma 18-250mm is a good lens at a great price, May 9, 2009
By W. Cooper (Santee, CA)
With lack of reviews on this product, it was a difficult decision to purchase this lens instead of the Nikon 18-200mm or Tamron 18-270. Since I was very happy with my Sigma 10-20mm lens, I thought it would be worth the risk--and it was, I am very pleased with all my test shots and look forward to taking it on my next outdoor adventure. This "super zoom" lens has great range, appears to have fairly sharp edges, low barrel distortion, and low bokeh effect. It is a good, solid lens with minimal zoom creep, and consistent feel throughout the zoom range. It focuses fairly quickly with the Hyper Sonic Motor (HSM), and the vibration reduction system (OS) comes in handy on those long range shots. This lens will probably spend 95% of it's time on my Nikon D60 camera. When combined with the Sigma 10-20mm, almost all my lens range needs will be met in a 2 lens kit.
Excellent Lens..., May 11, 2009
By Ghassan Bedaywi "Gus" (Kuwait)
Actually my review is somewhat similar to the previous review by W. Cooper. I, like him, didn't find much resources about this lens, but was confused between the Tamron & the Nikon long range lenses, I was about to go with the Nikon 18-200mm because I felt that the Tamron 18-270mm lens didn't really get good reviews and I didn't like the fact that it was slow in focusing. And boy am I glad that I waited for this one. I think I gambled (being an early adopter) and it worked.
Its really a great all around lens which is exactly what I was looking for (I hate changing lenses). The best thing about it is that its really pretty fast in focusing at 250mm, maybe even faster than my D90 kit lens the Nikon 18-105mm. It really is a HSM equipped lens, I saw a few threads in forums about ppl debating this fact, so rest assured it has a motor. The OS is working as it should at maximum zoom as well so no issues here. I have been using it for a couple of days only to be fair, but I'm very excited about it and about the quality of the images I have took so far. I'm taking it out for a full test in the next few days, if I feel that things weren't perfect I will update this review. I didn't notice a lens creep (yet!), but in any case there is a lock switch on the lens, this switch will only work when the lens is at 18mm. I noticed that when you are trying to shoot close-ups at 250mm, the lens wont focus properly if you are too close to the subject, manual focus will still work though and you can take a clear sharp picture. The make and the body of the lens feels nice and durable as well, it doesn't feel cheap at all.
In the end I have to say that this baby will beat the Tamron 18-270mm lens hands down, and surely the Nikon 18-200 if you want a bigger zoom. And the price is surely worth it and acceptable.
Update: I think I was wrong about close-up focus, it still focus pretty well and fast at close range while at maximum zoom.
Update 2: I have uploaded some pics in Picasa, plz see comments for link. The images don't look good after uploading to the internet.
v
Update 3: I have to confirm again my initial statement that sometimes it fails to auto focus at close range (according to my tests), I would have to use manual focus. Going back to auto focus it would then work, it seems it needs a reset from time to time!
Update 4: It weighs around 650g or 1.43 pounds.
Press Release
Thursday, 15 January 2009
Sigma 18-250mm F3.5-6.3 DC OS HSM
January 14, 2009: The Sigma Corporation is pleased to announce the launch of new SIGMA 18-250mm F3.5-6.3 DC OS HSM on March 10th, 2009.
The SIGMA 18-250mm F3.5-6.3 DC OS HSM incorporates Sigma’s original anti-shake compensation function, with a 13.8 times zoom ratio. As opposed to having an anti-shake function in the camera body, this lens’s Hybrid Optical Stabilizer provides not only an anti-shake function for the camera body, but also compensates for image shaking in the view finder as the Optical Stabilizer is built in to the lens.
Incorporating four Special Low Dispersion glass elements and three aspherical lens elements provides excellent image quality throughout the entire zoom range.
This lens has a minimum focusing distance of 45cm (17.7 inches) at all focal lengths and a maximum magnification of 1: 3.4 reproduction ratio, making it ideal for close-up photography. An inner focusing system eliminates front lens rotation, making it suitable for use with circular polarizing filters and the supplied petal-type hood. Incorporating super multi layer coating reduce the ghost in the backlight photography.