The five-year gap between the launch of the a7S II and the announcement of the a7S III had some people wondering whether Sony had given up on the idea of a video-focused a7 model. The enhanced video capability of the core a7 line made that seem plausible (the a7 III does many of the things the a7S II did).
But the Mark III is here and it represents more than just a Mark II brought up to competitive spec. Instead it’s the most serious video camera the Sony Alpha range has ever seen and makes the older camera look rather basic, by comparison.