cookedart

One thing I'm surprised that more people aren't trying is Sony's own LA-EA4 A Mount to E Mount adapter.. in theory you could attach the Tamron 24-70 in Alpha mount to the A7S. I literally have seen no one try this.. but if the lens works at all I'm willing to bet it will be less buggy and cheaper overall than the Metabones. Of course you'd have to find a suitable stabilized alternative to the 70-200 as well (would have to be a Sigma or Tamron in this case).

Another method to shoot 4K for 2K is to have the camera downcovert the signal over HDMI. It seems the HDMI scaling algorithm is way better than the line skipping algorithm they use on sensor. As such you get a sharper 1080p 10-bit 4:2:2 straight out of camera if you use 4K downcovert over HDMI. Downsides are the 2.3x crop and the 30fps limit, plus you lose the ability to possibly punch-in in post. Upsides are the noticeably increased sharpness and less noticeable noise pattern. And this way you skip having to downconvert it in post, which can help a lot with storage (4K 10-bit 4:2:2 files gobble up a lot of space, especially if you intend to output to 1080 anyways).

I don't have a test I can show but I can weigh in. I ran a test on all modes and didn't notice that much of a difference between the prores and the in camera hours, both at 200mbps All I and 100mbps IPB, as well as at 24 and 60 fps. What I did notice is that you can tell the camera to down covert the 4k signal down to 1080p. This does crop the image slightly just like the 4k setting, but it seems to use an entirely different imaging pipeline. Downscaling in camera is noticeably sharper than the normal 1080p setting. I also do notice some noise in the shadows at iso 200 and 400 using cine d. Still haven't figured out the best settings yet.