The Sigma 18-200mm f/3.5-6.3 DC OS (Optical Stabilizer) Lens offers an “all-in-one” super-zoom lens solution, from wide-angle to long telephoto. It provides the equivalent focal range of approx. 29-320mm when used with a Canon digital SLR camera(*). This lens has now been updated with the OS (Optical Stabilizer) system, which minimizes image blur caused by camera shake, and offers the equivalent of shooting at a shutter speed 2-3 stops faster. This allows handheld telephoto zoom shooting even in poorly lit conditions.

The 18-200mm’s optical design incorporates aspherical lenses and SLD (Special Low Dispersion) glass, which provides the utmost correction for all types of aberrations. It also enables this extended super-zoom lens to be housed in a compact and lightweight construction.

DC lenses are exclusively designed for digital SLR cameras. The image circle (rear of lens) is sized to match the smaller dimensions used for the image sensor on digital cameras. As a result these lenses are also more compact and lightweight, and are better matched to digital SLR cameras.

The OS system uses two sensors inside the lens to detect vertical and horizontal movement of the camera. It works by moving an optical image stabilizing lens group, to effectively compensate for camera shake. It automatically detects movement of the camera and compensates for camera shake when shooting moving subject such as motor sports.

• Two Special Low Dispersion (SLD) elements and three hybrid aspherical lenses provide high quality images throughout the entire zoom range.
• Super Multi Layer (SML) coating reduces ghost and flare.
• The lens design incorporates an inner focusing system, which prevents the front of the lens from rotating, thereby making it particularly suitable for use with circular polarizing filters and petal shaped lens hoods.
• A magnification scale is displayed on the lens barrel for each focal length, ensuring ease of use.

Reviews

Sigma 18-200mm f/3.5-6.3 DC OS HSM review by DPReview.com

Conclusion – Pros

• Huge 11x focal length range, ideal general purpose and travel lens
• Relatively low chromatic aberration
• Low distortion (for a superzoom)
• Reasonably effective optical stabilization system, 2.5 – 3 stops benefit

Conclusion – Cons

• Very inconsistent sharpness through the zoom range – extremely soft at 80mm
• Soft corners at all focal lengths
• Occasionally indecisive autofocus
• Slightly less resistant to flare than its more recent competitors

Sigma AF 18-200mm f/3.5-6.3 DC OS (Canon) – Review by photozone.de

The Sigma AF 18-200mm f/3.5-6.3 DC OS is an extremely versatile lens but performance-wise it is a bit of a mixed bag. The resolution characteristic varies significantly throughout its immense zoom range. Interestingly the extreme ends are actually the sweet spots of the lens whereas the 35mm setting is downright miserable at large apertures. The quality recovers at 50mm before dropping somewhat at 100mm again. To be fair the lens is capable to provide a decent quality if you avoid large aperture settings and stick to ~f/9 regardless of the zoom position. On the positive side vignetting and CAs are quite well controlled and distortions may be a problem at 18mm only. The quality of the bokeh (out-of-focus blur) is sometimes less than stellar though. The AF speed and accuracy is pretty fine and the image stabilizer can give you an advantage equivalent to about 3 f-stops in field conditions. The build quality of the Sigma is surprisingly good and above average for a lens in this class.