The size of the Micro Four Thirds system might surprise many DSLR owners, and many Micro Four Thirds camera owners too for that matter, as it has been growing at a pretty steady pace for the last six years. Between the 'big names' Olympus and Panasonic, and third-party contributors like Sigma, Tamron, Samyang, Voigtländer, Tokina and Kowa, there are now about 55 dedicated lenses available for Micro Four Thirds cameras. This exceeds by many times the size of the systems available to other compact system cameras, and in fact beats all in the DSLR market other than the Canon EOS system, for volume, if not for choice.

While Olympus and Panasonic get plenty of coverage for their optics, the independent brands (who may or may not also have a hand in the production of some lenses for the main players) have yet to make much impact - so here, to address the balance somewhat, we will look at the three DN lenses from Sigma. 

The Sigma 19mm F2.8 DN | A is a wideangle prime lens which offers a focal length equivalent to 28mm on Sony E-mount and 38mm on Micro Four Thirds. Optical construction consists of 8 elements, three of which are aspherical, in 6 groups. 
The Sigma 30mm F2.8 DN | A is a wideangle prime lens which offers a focal length equivalent to 45mm on Sony E-mount and 60mm on Micro Four Thirds. Optical construction consists of 7 elements, two of which are aspherical, in 5 groups. 
The Sigma 60mm F2.8 DN | A is a standard prime lens which offers a focal length equivalent to 90mm on Sony E-mount and 120mm on Micro Four Thirds. Optical construction consists of 8 elements, one of which is aspherical (shown in pink) and one of SLD (special low dispersion) glass. 

These lenses were launched at the CP+ show in Yokohama in January 2013, and while two existed already in Sigma's lens range, with the introduction of Sigma's Global Vision program the 19mm f/2.8 and 30mm f/2.8 have been revisited, refreshed and welcomed into the company's Art category. The 60mm f/2.8 is an entirely new design. 

Each of these lenses is also available in a fitting for Sony's E-Mount APS-C cameras, so the covering circle of the lenses is greater than that required for the smaller Micro Four Thirds sensors. This review primarily covers my experience with the M43 mount versions, but in the galleries at the bottom of the following pages you'll find several samples from Sony E-mount lenses, too. 

Build and construction

The exterior design of this trio is much closer to that of Sony's E-Mount lenses than it is to either Panasonic's or Olympus'. A pair of featureless barrels, one in semi-matte and the other in gloss, makes for a very simple style that is far more appealing once the lenses are mounted on a camera than when they are sitting adrift on a shop shelf waiting for a good home to come their way. Available in a rather tin-can silver or a smart black, the lenses are marked with the 'A' for 'Art' logo that denotes their category in the Sigma range.

Lens hoods are black whether you choose the silver body or not, and remarkably the same LH520-03 hood is deemed appropriate for each of the lenses despite the differences in their angle of view. Little things please little minds perhaps, but I was delighted that each also takes the same size lens cap and filter thread – even if it is of a less-than-common size; 46mm. 

When the lenses are loose, or attached to a camera that isn't switched on, they clunk quite alarmingly when tipped upside down, like one of those child's toys that moos and has a cow on the side. I can only assume that is the focusing group sliding back and forth, because as soon as the camera is switched on the group comes under control and, reassuringly, the clunking disappears. 

With no rubber grips or coatings these lenses are constantly cold to the touch, and their smooth finish doesn't leave us too much to hold on to. Fortunately then, their diminutive proportions mean they sit nice and securely in the palm of the hand. The modest maximum aperture of the trio has allowed the design to remain compact - or perhaps a desire to maintain a narrow barrel has dictated that we are deprived of apertures wider than f/2.8. I don't know which was the priority.

While I understand that their unified design makes a powerful indicator that these triplets are part of a set, it's hard to tell them apart. It didn't help that the paint of the 60mm became just scuffed enough that the 6 is hard to read. Despite all that, the lenses feel nicely made are solid enough to survive a good deal of use – and, in black at least, they are deceptively pleasing to the eye.