Sigma 70mm F/2.8 EX DG Macro
There are several macro lenses of around this focal length on the market that are specifically designed for APS-C cameras. But this Sigma is also full-frame compatible. The upshot is that, with the crop factor of most DSLRs on the market, you get an effective focal length of about 105mm, which is more in-keeping with the traditional 100mm focal length used for macro shooting on full-frame cameras.
However, despite its shorter focal length, there’s practically no difference in physical size between this lens and Sigma’s 105mm, also on test. This 70mm lens feels a little more solid, tipping the scales at an extra 67g. Build quality is good overall, with Sigma’s trademark matte black finish and a DF(Dual Focus), system in which the focus ring doesn’t rotate during autofocus, making for easier handling.
Switch to Manual
Autofocus proved a little ponderous and quite noisy in our tests, but suffered none of the stop-start lurching of the Pentax lens. Switching to manual focus can take a little more effort than you would expect, but it is a real joy once you get there since the specifically long travel of the focus ring, combined with the excellent smoothness in operation, makes for some highly precise focus adjustments.
For ex-film photographers that have got used to working with 100mm macro focal lengths, or thereabouts, the Sigma 70mm will give a comforting sense of familiarity, backed up by very good optical quality.
Sigma 105mm F/2.8 EX DG Macro
You can extend your range and your options with this Sigma macro lens. Compare with the Sigma 70mm, this lens extends your effective focal length on an APS-C camera from around 105mm to about 160mm, which is more in line with other lenses in the group. It also has the widest range of mount options, including Canon, Nikon, Pentax, Sony and Sigma, as well as being the only one that is available in Four-Thirds fit.
Indeed, on an Olympus DSLR with the use of the Four-Thirds fit, the lens has a mighty effective focal length of 210mm, enabling you to keep an even more discreet distance from targets during macro shooting. Olympus itself manufactures a 50mm macro lens for Four-Thirds fit, but it only offers a 0.5x (1:2) magnification factor.
Like the Sigma 70mm, this one has a high standard of build quality considering its competitive asking price, and the same DF (Dual Focus) system in which the focus ring does not rotate during autofocus. The autofocus itself proved a little silence and quicker, but there is still generous travel in the focus ring for precise manual adjustments.
Do the Two Step
Both Sigma lenses feature a push-pull arrangement in the focus ring for switching between autofocus and manual focus. However, in the Canon fit option, you also need to operate the AF/M switch on the lens barrel, making it a less than intuitive two-step procedure.
Optical prowess proved particularly impressive for macro shooting in the f/8 to f/16 aperture range, but sharpness fell off alarmingly at large or small apertures.