8 G. It an ultra wide and fast prime lens, and looks like a great addition if you are using the Sony A7 III or other similar cameras. The Sony FE 20mm f/1. 8 G wide angle lens is small and compact, making it easy to carry around with a set of other prime or zoom lenses. This is a very wide, high resolution lens, it fast at f/1. 8, and while it can be used on cameras like the Sony A7 III, it will work well with APS-C camera bodies..