Review of the Sigma 70mm f/2.8 EX DG Macro

www.sigma-imaging-uk.com We’ve looked at a few macro lenses recently, partly as so many are being released, and partly because there’s a lot of interest from readers. One of the reasons for this is that compact digicams all have macro modes, which has proved popular. When people upgrade to DSLRs, it’s a feature they would like to keep, but unfortunately a dedicated lens is necessary. So we come to Sigma’s latest. This is an EX DG lens, placing it in Sigma’s premium range and offering a ‘full frame’ imaging circle – so it can be used with APS-C sized sensors, full frame sensors and 35mm film cameras. If you’re using an APS-C type sensor, the 1.5x magnification offers a field of view equivalent to 105mm on a film camera. The lens is constructed from 10 elements in 9 groups and uses a Special Low Dispersion (SLD) optic and a pair of high refractive SLD elements to reduce aberrations. There’s a focus limiter switch to speed up AF, which also uses a floating focus system. Sigma EX lenses are always well constructed and this is no exception, with a metal mount, tough outer casing and good finish. At 527g, it’s quite hefty, reflecting the weight of the glass, and of course it has that fast f/2.8 maximum aperture. Bear in mind that shooting macro reduces depth of field quite dramatically, so you need to stop down for maximum sharpness. Image quality from this lens is great. It’s as sharp as a knife, with excellent contrast and resolution. Maximum resolution is around the f/5.6 to f/8 mark, with over 1000lw/ph in both corner and middle of the image. Chromatic aberration is also practically non-existent in the centre, though some minor edge CA is apparent. At £339, this is a considerably cheaper option than optics from some of the other camera marques, and for those macro specialists among you, it certainly represents good value and a sound investment.