I would make the choice based on input and output options. DV25 & DV50 the frame size is 720x480. For the X:1 formats (1:1, 2:1, etc), the frame sizes are 720x486. DVD frame size is 720x480. I would use DV for firewire, and DVD input/output from the system. If my input or outputs were MOJO then I would capture at X:1 resolution. John