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Reviews Sigma 170-500 mm f5-6.3 APO DG Telephoto Lens  |
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| Sigma 170-500 mm f5-6.3 APO DG Telephoto Lens |
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The first ‘long’ lens I ever had was one of the earlier models of this ultra-telephoto zoom, and I achieved some great results with it. In fact my first-ever published pictures were taken using that lens (and were actually published in this very magazine!). It became my workhorse lens until I graduated to its bigger brother, a 500 mm ‘prime’ lens, so when asked to review this new version I was keen to see what changes Sigma had made. Chris Galvin tells all.
Sigma 170-500 mm f5-6.3 APO DG Telephoto Lens Primarily an independent lens manufacturer, Sigma has just completed the process of revamping its huge range of lenses and optimising them for digital photography. The company now badges such lenses ‘DG’, and has used a new multi-layer lens coating and design that reduces flare and ghosting. According to Sigma: “This lens uses one aspherical lens and three SLD (Special Low Dispersion) glass elements for excellent correction of all types of aberration, making high-quality images a reality throughout the entire zoom range.” But enough of the blurb: does it take sharp pictures? I found that I could indeed achieve sharp images which showed no sign of colour fringing or distortion. The rear focusing mechanism achieves a fast autofocus and, as the objective lens does not rotate, a circular polarising filter can be fitted. The autofocus switch is small and located on the left-hand side of the lens behind the tripod collar – in my opinion dangerously close to the lens release button of my camera. The lens appears to ‘hunt’ less on AF than I remember from previous models, but the motor still emits a high-pitched whine while focusing. Having spent money on revamping this lens, I can’t understand why Sigma has not incorporated its Hypersonic Motor for quieter highspeed AF, as it has with its 50- 500 mm and 70- 200 mm zooms. When the lens is coupled with a 1.4x converter, you lose the AF function and have to switch to manual focus. Also revamped are the focusing and zoom rings on the body of the lens. The smooth rubber of the earlier models has been replaced with chunky, easy-grip raised rubber ribbing, making operation easy with cold hands or while wearing gloves. Canon users should be aware of one particular problem. I found that with this lens I could not mount my 20D camera onto a tripod head if I had the additional battery pack attached. The rotating and removable tripod collar of the lens was too close to the camera mount to allow me to attach it to a Manfrotto 128 RC head. I had to either reverse the head and have the panning handle of the head on my left side, or remove the battery pack. As digital SLRs have become more affordable, more and more birders can be seen in the field with a digital SLR slung over one shoulder. This lens is light enough, at 1,345 g, not to be a burden during a full day of birding. Retailing at around half the price of comparable lenses offered by the camera manufacturers, this lens delivers a high performance introduction to bird and wildlife photography at an affordable price. |
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