Sigma Imaging (UK) Ltd

	Dr. Andrew Stevens - British Journal of Photography - January 2005 'The lenses are stylishly presented in a black satin finish and incorporate a manual / auto focus, along with focus range limiting switches. ...Both lenses have a maximum aperture of f/2.8 and, in the case of Sigma, Canon and Konica Minolta mounts, there is an unusually small minimum aperture of f/45 (f/32 for Nikon and Pentax). Although diffraction reduces resolution at such settings - f/45 becomes an effective f/90 at 1x magnification, approaching pinhole dimensions - this can provide beautiful effects with some shots and Sigma is to be applauded for providing this option. Both lenses produced excellent results, with fine detail and smooth tone gradation over a range of magnifications.'

	Digital Camera - June 2006 ‘The manual focus setting is firm enough for confidence and provides accurate control in close-up and telephoto use.’ ‘The Sigma in particular produced razor-sharp images at close quarters, and held its performance admirably throughout all the imaging tests we subjected it to, with constantly good detail and strong contrast at the telephoto setting.’

	Ephotozine - May 2006 ‘A good lens made better. The improvement in contrast and extra control of flare and ghosting provided by the DG coating are, in themselves, worth the upgrade. Improvements have also been made to the hood along with a reduction, albeit slight, in the AF noise. Optical quality cannot really be faulted and with the edges performing as well as the centre on a cropped camera you can expect good edge performance on a full frame body too.’

	What Digital Camera - August 2006 ‘The lens has a dual focus function: the focus ring snaps backward and forward between manual and autofocus, making critical adjustments easy and quickly. If you use AF, the lens has a limiting switch so focus stays within a narrow range. Where the Sigma 105mm optic performs well is in its control of chromatic aberration, which remained insignificant throughout the aperture test both in the centre of the frame and at the corners.’

	Which Digital Camera - September 2006 ‘The manual focus ring is disengaged by a very positive pull/click backwards, allowing the AF to operate without turning the manual ring.’ ‘A superb lens that’s excellent value for what you get. This lens will deliver to even the most critical users.’

	Photography Monthly - September 2006 ‘Optically there’s nothing to moan about - this is one fine lens.’ ‘It’s a real cracker and its showing even at f/45 is impressive. Top value, too, and with the advantages that it’s available in most fittings.’

	Practical Photography - March 2007 ‘The Sigma 105mm has proved to be a popular lens, its combination of ideal focal length and fair price winning many photographers over. Of course, it’s 105mm effectively becomes a 157.5mm when coupled with most D-SLRs and this can be helpful when photographing insects that are spooked if you get too close.’

	Digital SLR User - July 2007 ‘In terms of images produced there is very little to distinguish the Sigma from the equivalent branded lenses. Lens flare is low and there is good contrast across a range of shooting conditions.’ ‘An interesting feature of the lens (appearing in all mounts apart from Nikon and Pentax) is a minimum aperture of f/45, which of course produces a decent depth of field even when working close-up.’

	Amateur Photographer - 25th August 2007 ‘The Sigma 105mm f/2.8 performed excellently. In the important parameter of drawing accuracy, which is essential for a true close-up lens, it was particularly precise. At 1:1 it just had the edge of the regal Nikkor.’ It is a very modern lens with a crisp definition and contrast on the high side that contemporary trends favour.'