The manual focus ring is smooth and effective in use, enabling greater precision than in the Nikon 40mm lens. Barrel distortion can be noticeable, more so than in most competing lenses. Sharpness could also be better at f/3.5, especially considering the comparatively narrow maximum aperture. Arguably the most versatile lens in the group, the Sigma 105mm works brilliantly for both close-ups and portraits, while also having a fast ring-type ultrasonic autofocus system that makes it suitable as a fast, short telephoto lens for action photography.
Upmarket features include a three-position focus limiter switch enabling short, long or full focus travel. There’s also a highly effective dualmode optical stabiliser, with a dedicated switch on the barrel that enables selection of static or panning modes. Focusing is fully internal, so the overall length of the lens remains fixed throughout the focus range.
Build quality feels rugged, although there’s no weather seal on the mounting plate, as fitted to all three Nikon lenses and the Tamron 90mm VC USD. Little extras include a hood adaptor that maintains optimum effectiveness on either FX- or DX-format bodies.
Fast autofocus is matched by smooth and precise manual adjustment. Image quality is simply superb, even when using the widest available aperture. We thought this lens was outstanding value a year ago, and since then Sigma has knocked a third off the price, making it all but irresistible.