David Mullen ASC
Moderator
The data rate should be 1/4 less for the finished scaled image, but you have to factor in the processing to scale it from 4K to 2K. But once it is scaled, recording it at 2K to CF cards should be no different than recording 2K windowed material. So I don't think it is a recording issue, high frames for 2K scaled, but a processing issue, since you are essentially really shooting 4K at high-speed, then scaling it down to 2K in real time.