Performance

On an Olympus, the Sigma seems to behave just like any Micro Four Thirds lens would. Autofocus acquisition is rather snappy, especially when the lens doesn't need to move far to acquire focus. It is almost identical in speed to the Panasonic, once again giving a slight edge to the more expensive glass, which makes this next finding quite a surprise. Mount the Sigma on a Panasonic, in this case the GX8, switch it to AF-C, and the Sigma behaves much like a native Panasonic lens. It starts doing the rapid trademark wobble of Panasonic cameras, and is surprisingly quick for a camera relying on only CDAF. So, in terms of AF performance, the Sigma is at no great disadvantage over the Pana-Leica.

Manual focus for both lenses is focus-by-wire, but the Sigma foregoes the linear response of the Panasonic for a movement that speeds up depending on how rapidly the focus ring is turned, making like difficult for video shooters. Thankfully, there is no stepping or jerkiness to the focus elements movement, regardless of how quick it is trying to respond.

The question now is, does the extra 10mm of magnification make the lens a long normal or a short portrait lens? In use as a portrait lens, it does very well. Backgrounds experience a significant amount of blur wide-open, especially when a subjects face fills a large part of the frame. Depth of field is shallow enough that even when they don't take up as much of the frame there's a clear separation between the subject and background. It won't replace a longer dedicated portrait lens like the Olympus 45mm F1.8 or the expensive 42.5mm F1.2 Noctilux from Panasonic, but for those who can't afford the latter it has a useful look and characteristic, with the wider field of view providing the ability to add a sense of place to portraits.

As a normal lens, the framing is a bit tight. For some it might not be wide enough, but learning to work within its boundaries can produce some nice results, and some may feel completely satisfied never removing this lens from their favorite 4/3 camera, although the Panasonic with its 50mm field of view is more versatile in this respect than the Sigma.

Conclusion

While the Sigma 30mm F1.4 DC DN | C was a breath of fresh air in the rather sparse E-mount environment, it faces much tougher competition from the Panasonic Leica DG Summilux 25mm F1.4 ASPH. The Sigma ends up coming close or matching the Panasonic in several parameters, even though it is slightly behind in center sharpness. For a lens that costs less than its competitor, it is a solid performance. Its slightly uncommon focal length might not be for everyone, although its bright aperture makes it very usable for portraits. Unlike the APS-C version which undoubtedly sits atop the E-mount range as one of the sharpest lenses avaiable, the Micro Four Thirds version falls behind lenses available in that mount's more diverse lens selection. That said, offering a large portion of the performance of a more expensive lens for less price earns the Sigma a respectable Silver Award.

Sigma 30mm F1.4 DC DN | C for Micro Four Thirds
Category: Normal Lens
Optical Quality
Build Quality
Autofocus
Ergonomics and Handling
Value
PoorExcellent
Conclusion
The Sigma 30 F1.4 DC DN | C is a great autofocus F1.4 option for Micro Four Thirds. While it doesn't take the top spot for sharpness, it offers good, consistent performance across the frame for much less price than the competition.
Good for
Portraits, subjects needing shallow depth of field
Not so good for
The field of view is a bit too narrow to be a do-it-all prime
84%
Overall score