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.

? 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.

? 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...

A great lens which has taken so many good photos for me, I would certainly recommend this lens

cheaper than official Canon; sturdy; reliable; great zoom range; fairly good focusing; great picture

lens creep; a bit heavy; could possibly be built with better f stop

I spent a lot of time comparing this lens with others as a potential replacement for the Nikon 18-55 kit lens and the Tamron 18-200mm I had been using as a Hiking Lens. I gave the Tamron away and decided on the Sigma following detailed study of DPreview.com great lens sharpness and performance...

The Sigma 18-200mm F3.5-6.3 DC Macro OS HSM ($399) is, considering its zoom range, a fairly compact all-in-one lens that's available for Canon, Nikon, Pentax, Sigma, and Sony APS-C cameras . In full-frame terms, it covers a 27-300mm field of view.

Long 11.1x zoom range; Compact; Maximum 1:3 macro magnification; Optically stabilized; Compact; Available for most APS-C camera systems; Attractive price tag

Sharpness suffers at maximum aperture; Distortion throughout zoom range

This is an upgrade to my previous Sigma 18 - 200 which I accidentally dropped. It is lighter than the last one. Of all lenses of this type I have tried, Sigma always come out top for me in terms of sharpness. It is a great lens for travel and goes well with my Canon EOS 700D.

Durable; Lightweight

This is one of the cheapest lens in this category, and it's available in Canon, Nikon, Pentax, Sigma and Sony mounts. It doesn't offer image stabilisation, and so is best suited to cameras with on-board IS.

Price; great chromatic aberration control

Inconsistent performance; low resolution at 200mm

The Sigma 18-200mm F3.5-6.3 DC Macro OS HSM ($399) is, considering its zoom range, a fairly compact all-in-one lens that's available for Canon, Nikon, Pentax, Sigma, and Sony APS-C cameras. In full-frame terms, it covers a 27-300mm field of view. It can't match the optical quality of a prime lens, or Sigma's much larger and shorter 18-35mm f/1.8 zoom, but images throughout the zoom range are very useable, and sharpen up nicely when the lens is stopped down. The 18-200mm measures just 3.4 by 2.8 inches (HD), which is quite compact when you consider its zoom range. It does extend when zooming, doubling its height at 200mm, and it's not that light at 15.2 ounces. The front element is static during zoom and focus, so using a polarizing filter is feasible; the lens has a 62mm filter thread. A reversible lens hood is included. There are two control switches on the lens barrel—one toggles image stabilization (unless it's paired with a Sony or Pentax camera; they have in-body stabiliz...

The Sigma 18-200mm F3.5-6.3 DC Macro OS HSM lens trades some optical quality for a compact design, low cost, and long zoom range.

Long 11.1x zoom range; Compact; Maximum 1:3 macro magnification; Optically stabilized; Compact; Available for most APS-C camera systems; Attractive price tag

Sharpness suffers at maximum aperture; Distortion throughout zoom range

Can anyone compare Canon EF 28-135 IS USM to Sigma 18-200 DC OS pls. Equivalent IS and sharpness

If you are on a budget and you are looking to add a new lens to your SLR

Although this is a nice lens, I'm disappointed that the one I received is less than stellar as it has quite a bit of dust inside as well as it tends to "vibrate" at times when you press the shutter button half way down. Am hoping that this company does the right thing & correct the issue.