The Sony A7S II had a lot to live up to considering low light performance and it has so far been exceptional. But the question about slow motion quality lingered as to a new Spec of 1080p 120fps would perform compared to the previous 720p 120fps and to regular 1080p 60 video. New video tests have surfaced that show how good and or limited the new slow motion spec is on this camera. Many will be satisfied with just the 4k video at astounding levels of ISO which short of the Canon ME20F-SH with 4 million ISO it is the best second option with more resolution at a Max ISO of 409,600.
The Slow motion spec seems to be somewhat limited in quality compared to normal video on the Sony A7S II with a reported 20Mbit/sec for 120fps which is the 100Mbit/sec camera spec stretched 5x to playback at 24p. 20 Mbit is’t that bad considering it is 1080p and the artifacts are well controlled. There are some here and there including some compression macro-blocks if you search for them but for the vast majority of users the camera has a very good slow motion mode built in; albeit at 120fps as it will go no further up the frame rate scale.