Some may know that I did some tests comparing/contrasting the AX100 4K 100 mbps XAVC-S and the X70 4K 60 mbps XAVC-L. These tests were of virtually the same footage shot at the same time and projected in 4K onto a 15-foot screen in a high-end 4K color grading suite here in Los Angeles. In the opinion of two cameramen and two colorists present (one of them the senior colorist), while both cameras looked excellent, the X70 images looked slightly superior. They definitely graded better.
There have been various discussions about why Sony didn’t put 100 mbps in their professional camera but did so in the consumer version. Briefly, the two codecs are significantly different and the professional codec performs better.
I just received this word from Sony’s X70 product manager regarding possible future 100 mbps in the X70: “We are working on that, but have not clarified whether or not whether it is technically feasible to incorporate 100Mbps. It is different from those of consumer FDR-AX100 and other models.”