In use

At first I thought it strange to have a smooth focusing ring, as traditionally focusing rings are heavily textured to provide a good grip and to improve response to touch. In action though I found that these rings turn very nicely, and while perhaps we may not expect the gloss finish to give as much grip as deep cross-hatched rubber, to bare fingers there is plenty of friction and stickiness to make the ring turn easily. In cold weather those with soft gloves may have a different experience though, especially if trying to focus with one finger, Leica M style – but the barrels are all slim enough that two-fingered pressure can be applied from either side of the lens. 

The movement of the focusing rings has a very pleasant resistance. The sensation here is of control and accuracy.

From a standing start these lenses get into gear and make themselves ready to shoot in much the same time that similar Panasonic and Olympus models do. The speed of AF acquisition seems not to be hindered at all by the reduced illumination of the f/2.8 apertures except in the dimmest of conditions.

I was a little concerned that the front element of the 30mm is particularly small, with a diameter of about 15mm, which made me slightly compulsive about keeping it clean. The other two lenses have front elements more in-line with the size of other fixed focal lengths for the system, though in the event I didn't experience any flare or loss of contrast due to fingerprints or dust, or otherwise, with any of the lenses. 

Performance on Micro Four Thirds bodies

This isn't intended to be a test-and-measure article, but there are a few things that I noticed that are worth pointing out – even without the assistance of test charts. The first is that in terms of center-to-edge sharpness and vignetting each of the lenses performs in a very similar way. Predictably enough, none of the three manages to match corner and center sharpness until apertures are closed by a couple of stops, though each performs well enough wide open for pictorial subjects, if not for technical copying.

I tend to put my focus point and subjects well away from the center of the frame, and enjoy the shallow depth of field that a wide open aperture delivers. Fortunately, I didn't have to regret the combination too often. 

ISO 3200, F2.8, 1/400sec. Sigma 60mm. mounted on a Panasonic Lumix DMC-GH4, converted from Raw 'to taste'. Download Raw file

Each of the lenses uses 7 rounded iris blades which, combined with the optical construction of these models, makes for very attractive out-of-focus highlights when wide apertures are in use. Highlights remain mostly rounded and reasonably smooth and featureless. 

Performance on Sony E-mount bodies

by Samuel Spencer - DPReview Studio Mgr.

While there is an abundance of lenses for the Micro Four Thirds cameras in all price brackets, the Sony E-mount does not have quite the same selection. Sony makes a handful of inexpensive entry-level primes, but the Sigma DN pricing still comes in below those. With the recent drop in the 60mm's price, all three of these lenses can be had for just over the cost of a Sony a6000 body only. 

ISO 100, F11, 1/8sec, taken with a Sony a6000. Download original Raw file

At F11 on a Sony a6000, diffraction has taken the edge off sharpness in this shot, taken with the 19mm F2.8. A relatively large-radius sharpening pass in Adobe Camera Raw has crisped things up nicely without causing any serious image degradation. 

There are one or two catches that should be noted with that purchase. Sony's entry primes are both faster and offer OIS, although of course that comes at an extra cost. The biggest catch when using these Sigma lenses (especially on the a6000) is the limited use of PDAF autofocusing on these lenses. Instead of the brilliant complete coverage that the a6000 is known for, the system becomes limited to the center of the frame. In the case of the 19mm, where sharpness decreases off center, this might not be too huge of a loss.

I found it most frustrating on the 60mm, where focus was the most critical. When the subject is in the PDAF-enabled area, it works very well and still does the intelligent subject tracking, but as soon as it falls out of that area it starts to hunt and can lose the subject.

ISO 100, F8, 1/125sec.

The 30mm F2.8 makes a 45mm (equivalent) prime on Sony's E-mount platform. This is a perfect walkaround focal length, suitable for a wide range of subjects including portraiture and details. 

Honestly, at this price point complaining about these things feels a bit petty. Just $600 can get you three lenses. That's great. You can get one for $200 (I'd personally had the most fun with the 19mm). If you're holding off on purchasing a Sony a6000 because a decent prime puts you out of budget, one of these Sigmas will get you going, and the results are great for the price.