This full-frame lens from Sigma offers 1:1 magnification with a minimum focus distance of 31.3cm. Like its 50mm sibling the fast aperture can be stopped down to f/45, or f/32 on Pentax and Nikon bodies. On most APS sized cameras, the lens has a 1.5x magnification effect offering 157.5mm equivalent in 34mm terms – or an angle of view of around 23°, if you need to know.

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, because it remains insignificant throughout the aperture test both in the centre of the frame and at the corners.

In terms of sharpness the lens is a reasonable performer, and produces decent results, but suffers when placed in comparison to others, with generally consistently lower MTF measurements than comparable lenses.

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Verdict

Another reasonably priced lens offering decent if not mind-blowing images