Sigma 18-250 mm F3.-6.3 DC OS Zoom Lens Review
Today almost all digital SLRs are equipped with a zoom lens. My Nikon D90 came with a 18-105 mm zoom, for example. 
Even though a range of 18-105 mm sounds good, it quickly becomes clear that a greater range is desirable.
One of the most versatile lenses I have come across in terms of range is the Sigma 18-250, which is a digital only 29-400 mm (35mm film) equivalent. Because it can go from wide-angle to telephoto to close-up – all with one lens – it is the perfect addition to the business traveler/photographer’s arsenal.
The lens itself is finished in an attractive, matte-black, with easy-to-read scales. At 18 mm, it is fairly compact (the 4” body is only slightly longer than the company’s 18-200 mm F3.5-6.3 OS lens). It’s also relatively light, only 22 ounces,an important consideration in choosing a lens. The lens includes a Hybrid Optical Stabilizer that provides an anti-shake function that is particulary useful under low-light conditions.
With a minimum focusing distance of 45 cm and a maximum magnification of 1:3.4 reproduction ratio, it is ideal for close-up photography.
The auto-focus function (tested on the Nikon D90) is very fast, even in low light situations, and it is fairly quiet as well.
Image quality is superb. Sharpness and contrast are excellent but there is some deterioration at the longest focal length, although this is quite normal for superzooms such as this.
The Sigma 18-250 mm is available in Canon, Nikon, Pentax, Sigma, and Sony/Minolta mounts and, at $800 retail, costs far less than similar lenses from camera manufacturers.
With its extended range, optical stabilization, great image quality, and light weight, the Sigma 18-250 is the perfect companion for your next trip.
–Jonathan B. Spira is the Editor of Executive Road Warrior and Chief Analyst at Basex, a knowledge economy research firm.
