By technical editor Matt Allard:
At CP+ in Japan Sony were showing their new FE 28mm F2 lens. This full frame capable E mount wide angle lens is compact, light weight and features a 49mm front diameter. Sony has designed a Fish Eye Converter as well as a Ultra Wide Converter to work with only this lens. Neither adapter will work on any other E mount lenses. The Ultra Wide Converter will give you a full frame field of view of 21mm, while the Fish Eye Converter will give you a 16mm full frame field of view.
The 28mm is a small, and the optional adapters weigh almost as much as the lens. The build quality is fair, but not in the same class as the 35mm F1.4 FE ZE. From my quick play with the lens, it optically looked pretty good. It also had pretty close focus ability that I estimated to be around the 30cm mark. Once you put the adapters on expect a drop in optical performance. The Ultra Wide Adapter had quite a lot of barrel distortion and definitely looked a little softer in the corners. The Fish Eye Adaptor does produce minor vignetting in full frame mode.
There is no pricing or availability currently announced by Sony.