10 out of 10 points and recommended-High image sharpness to the corners at most stops; Lack of CA problems in both in and out of focus areas; Low price; Versatility (excellent for macro with added achromats, and also excellent for infrared photography)- The slippery focus ring (solvable)
From http://www.david-ruether-photography.com/MFT-Lenses.htm#N (photo samples are also there) --reviewed March 24th, 2016 (purchased for $229)
I had seen a couple of positive reviews of the Sigma 60mm f2.8 lens (which is offered in both Sony NEX and Panasonic/Olympus MFT mounts, with electrical contacts for AF, AE, and EXIF) and also the sample photos that were included, but they did not prepare me for what this relatively inexpensive lens can do! I have many Panasonic (and also some Olympus, Voightlander, Tamron, Nikon, and Rokinon) lenses that work well on my Panasonic MFT bodies, but this lens beats almost all of them for optical quality. It is sharp to the corners wide-open at f2.8 (and it's also good even when well stopped down); it does not flare; there are (so far) few observable ghosts from strong light sources being either within or outside of the frame edge; there are essentially no CA problems, even under very difficult conditions, which normally result in noticeable CA problems with most other lenses (and which do show prominently with the two shorter FL Sigma f2.8 lenses in the same line-up, the 19mm and 30mm lenses); there is very low linear distortion; this lens remains sharp over a wide range of focus distances (which is not true for all lenses); this first sample I tried appears to be well-aligned optically and mechanically, something that is all too rare (lens samples often do vary, sometimes considerably, regardless of brand or cost); AND, this is also one of the sharpest lenses I have yet found for shooting infrared photos (about half of my lenses are not very good for infrared photography). I - am - impressed! Its minor irritations: a slippery-smooth focus ring makes the lens somewhat awkward to focus manually and also to hang onto securely; there is no internal stabilizer; it doesn't mount onto the camera as smoothly as other lenses and adapters that I have; it doesn't focus very closely (but I have some good achromatic close-up lenses that fit on its front to cure that shortcoming); the included shade is at best just OK (so I use a different shade); the internal focusing section rattles fairly loudly unless the power is on (but this is normal for this lens); and the plastic front doesn't even pretend to speak "quality-construction") - but all of this becomes meaningless when one sees what its image-quality is like, even from wide open, even to the corners (on MFT). I use a wide rubber band on the focus ring to "cure" the most important deficiency/quirk in the design, and this works well enough. I LIKE THIS LENS!
10 out of 10 points and recommendedSharp to the corners over a wide range of stops; Low CA; Excellent for infrared photography; Compact and light-weightNone (other than for not having in-lens stabilization - but I don't find this a problem for my use)
From http://www.david-ruether-photography.com/MFT-Lenses.htm#25mm (photo samples are also there) -reviewed March 24th, 2016 (purchased for $99)
This compact, fast, and light "normal" lens for the MFT format performs very well over a wide range of stops (from wide open at f1.7 to a bit beyond f11). For many purposes (including for shooting infrared photos, for which it is excellent), this lens is a very good choice since it is sharp to the corners even wide open, and (on Panasonic bodies, which automatically correct in-focus CA with JPGs) it exhibits few CA problems even when used under the most difficult conditions. This lens is another "keeper"!