Sigma’s EX DN lenses were available from March 2012, in the original rubberised design that reflected the lens range at the time. The new Art series lenses are a similar specification, but carry the new engineering and design language of Sigma, with testing on the Foveon-based system and further improvements in build and optical quality as a result.

With the performance of the full-frame 35mm Art so groundbreaking, it would be unfair to assume that these low-cost, small image circle lenses are going to perform at that level, but the Global Vision ethos for Sigma is showing a renewed vigour for exceptional quality within the budget. We’ve high hopes for the DN series, particularly on the flattering OM-D which will be using a smaller area of the image circle.
 


First impressions, particularly when alongside Olympus’ own brand lenses, are of a truly high-quality product. Sigma package the Art lenses attractively, with a lens hood and strong, protective keeper case included as standard, well designed and branded rear caps and the new substantial pinch-release design lens caps. A metal mount contributes to a feeling of solidity and the smooth focusing ring forms most of the lens depth. Some users may prefer the rubber grip style, but as the majority of mirrorless users rely on autofocus, the reduced risk of accidental focus adjustment is an overall gain on the design. In fact the metal collar features a fine texture engraved surface that makes it surprisingly grippy when held intentionally.
Unlike many Olympus lenses, the Sigma lenses include a hood as standard.
 

 
Lightweight optics ensure a fast AF system. On the Olympus, the 30mm F2.8 DN was able to track strongly wind-blown flowers, maintaining focus across dramatic shifts in position. The minimum focus of the 30mm (60mm equivalent on Micro Four-Thirds, 45mm on the APS-C NEX system) is an impressive 30cm; the reproduction ratio of 1:8.1 is far from any macro aspirations, yet you can get close enough for the 30mm to be a nice general purpose lens.

On the OM-D both the 30mm and 19mm handle beautifully. Well weighted, they complement the compact body and look attractive, almost more high-tech than the retro Olympus design. Silver variants are offered for silver bodies; the only distracting element of the design is on the left side of the lens, where a large amount of text including the serial number seems oddly prominent. In an era of designs produced in factories in Vietnam and Malaysia to cut costs, the words Made In Japan are reassuring. Sigma’s development and testing remains firmly in house, even for products with a low retail price.
 

 
Despite the lenses lacking optical stabilisation, they rattle when not connected to the body and powered up. The fast and silent lock is achieved in part by having a floating focusing group that reacts almost as quickly as the stablisation elements in larger lenses. Focus is so quiet, you have to hold the lens to your ear to hear it in action, and even then, it’s a soft click, rather than the whirring of in-lens or in-body motors larger SLRs often produce.

In use it’s hard to fault the DN lenses. Already notable performers in their original form, any engineering modifications have served merely to refine an already winning design. The 19mm (38mm equivalent) on our test OM-D showed no falloff, exceptional sharpness fully open and great contrast.
These examples are straight from the 30mm right after unpacking – we’ll have more soon. F2.8 on the OM-D allows for good depth of field control, with smooth bokeh and no evidence of aberration, distortion is also minimal.
 

 

 

 
And a few quick 19mm examples.

 

 

 
With both lenses performing so well, the recently announced 60mm (120mm equivalent for the Micro Four-Thirds owner) offers a great deal of promise, particularly with Sigma’s new design and testing methodology.