The Sigma 18-200mm f/3.5-6.3 DC lens is specially optimized for digital SLR cameras, and offers an “all-in-one” super-zoom lens solution. This lens provides the equivalent focal range of approx. 29-320mm when used with a crop body.
It’s design incorporates aspherical lenses and SLD (Special Low Dispersion) glass that provides the utmost correction for all types of aberrations and 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 made 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.
- Super Multi Layer (SML) coating reduces ghost and flare
- Two pieces of Special Low Dispersion (SLD) elements and two hybrid aspherical lenses provide high quality images throughout the entire zoom range
- The lens design incorporates an inner focusing system, which prevents the front of the lens rotating, 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
This lens once again proves that it is extremely difficult to produce the ideal all-in-one lens. Whilst this one is very good at the wide end, it does start to show the limitations of the design type at the long end. But if you consider the advantages of just having the one lens and the reduction in lens changes that could let in dust, there are some saving graces. All in all it is a nice lens if you can put up with the long end fall off.
In summary the main positive points of the Sigma 18-200mm f/3.5-6.3 DC are:
- Performance at wide end
- Focal Range
- Size and weight
- Easy Manual Focus
Negative points are:
- Optical quality falls off towards telephoto end
- Autofocus a little noisy and slow.
- Highly versatile 11.1x zoom range
- Great value
- Relatively small and light – great travel lens
- Polariser-friendly internal focusing
- Tamron version very similar
- Pricier Nikkor version has anti-shake
- Pricier Nikkor version is optically faster
- Pricier Nikkor version has better build quality
The Nikkor 18-200mm is clearly a superior lens in many respects, but only you can decide if its benefits justify paying twice the price of the Sigma or Tamron. While we at Cameralabs believe its worth spending the extra on the Nikkor if you can afford it, anyone on a tighter budget can’t fail but be impressed by the sheer value of the Sigma and Tamron lenses. They both offer a very impressive deal for the money and come recommended.