It would be nice to get a 2mb still from a D4 film, but my "clips" consistently seem to be in the 1mb range. But, they are relatively bland indoor shots of people, so there may only be 1mb of information to capture.
I shoot D4 movies at 24fps (rather than 30fps) to save card space and either A or P mode. But, unless the D4 is set to Manual, the camera's program takes control and dials the ISO way down (to ISO ~560 even indoors) from the ISO I am using for indoor stills (8000 or higher). This means that the other settings are sub-optimal.
I have discovered that D4's Face-Priority Auto-focus in movie mode is buggy. I recently did some oral history and was very disappointed with the results. Despite the camera being mounted on a tripod, the subject being stationary, and the photographer not touching the camera or lens after starting the recording, the D4 engages in persistent auto-focus activity that: (a) moves the focal point slightly forward and back, reducing the quality of the video recording: (b) makes noise, reducing the quality of the audio recording; (c) sometimes changes the exposure value, causing the image to lighten and darken, reducing the quality of the video recording. Similar problems are observed with other video settings.