I hate to be a Debbie Downer, but if the LS300's sensor is the AltaSens AL41410C, the dynamic range is theoretically only about 10 stops, and that's with a rolling shutter. As to whether the the 4K is 4:2:2, I suspect it is. JVC also announced the GW-SP100E remote head camera system, which seems to use the same sensor. Among the specs: "Up to 4K Ultra HD 50/60p recording at 4:2:2 150 Mbps" and "4K single file recording at 150 Mbps." I assume that if the GW-SP100E can record 60p 4:2:2 at 150 Mbps, the LS300, at 24/30p and 150 Mbps, is probably also doing 4:2:2. I suppose the latter spec means that JVC isn't using their goofy process of simultaneously recording to four SD cards, RAID-style, but is recording as a single file.