The barrel has a large zoom ring and a small manual-focusing ring at the front, with a zoom scale marked at 18, 24, 28, 35, 50, 80, 135, and 250mm. The three switches on the barrel include Zoom Lock, AF/MF, and stabilization ON/OFF.

Sigma's new 18-250mm f/3.5-6.3 DC OS HSM is designed as an all-in-one lens for digital photographers with APS-C-sized (DX) sensors who don't want to carry more than one lens. Covering focal lengths ranging from the 35mm equivalent of 27mm to 375mm with most camera brands (28.8mm to 400mm on Canon...

A one-lens solution like this 18-250mm Sigma optic is a very popular option with photographers, because you only need to attach the one lens to your camera and you can enjoy a whole range of shooting options.

There is an underlying desire in every travel or street photographer to be able to carry one lens to cover all contingencies.

The WDC Sigma 18-250mm f/3.5-6.3 DC SLD OS HSM lens review discovers whether this is be the best all-round, third-party DSLR superzoom lens on the market.

Effective optical stabilisation

Focusing ring rotates in AF

Sigma's lens was tested here using a Canon EOS 40D, on which it focused reasonably quickly (but not remarkably so) and very reliably. Sadly, but not unusually for a lens of this type, the focusing ring rotates and there is no option to apply adjustments when the lens is set to AF mode.

Effective optical stabilisation

Focusing ring rotates in AF

The Sigma 18-250mm F3.5-6.3 DC OS HSM, perhaps unsurprisingly, seems very much to be a case of 'take the 18-200mm OS , make it longer', and exhibits much the same characteristics as the older design.

Huge 13.9x focal length range; ideal general purpose and travel lens; Good image quality in the wide to short telephoto range; Fast; quiet autofocus; Low distortion (for a superzoom; Good build quality; smooth zooming action and no zoom creep

Very inconsistent sharpness through the zoom range - extremely soft at 135mm; Soft corners at almost all focal lengths; Image stabilization not as effective as on similar lenses; especially at telephoto end

Huge 13.9x focal length range, ideal general purpose and travel lens; Good image quality in the wide to short telephoto range; Fast, quiet autofocus; Low distortion (for a superzoom); Good build quality, smooth zooming action and no zoom creep;

Very inconsistent sharpness through the zoom range - extremely soft at 135mm; Soft corners at almost all focal lengths; Image stabilization not as effective as on similar lenses, especially at telephoto end;

I bought this lens to travel with so I don't have to carry multiple lenses and am very happy with it. I used the Tamron 19-270 equivalent for a few days and found it to be poor quality, didn't want to spring for the Nikon 18-200, and didn't like the midrange distortion that reviews show in the Sigma...

Versatile

Need Separate Flash

Very convenient lens. Get this one with my 500D is a nice combo. No need to change between the 17-55 IS and 70-200 L as before. I can leave the two lenses at home and travel light with only one lens. IQ is OK.

Very useful zoom range; fast and near silent focus; reasonably sharp from 18-80 mm

Very convenient lens; Get this one with my 500D is a nice combo; No need to change between the 17-55 IS and 70-200 L as before.