I have made some tests on rolling shutter. I tried to found the readout speed. The sensor is an expeed 3, faster than predecessors but always slow!
On my tests the readout speed seems to be about 0.0155 seconds shooting at 1280×720 60 fps. Offset in frames at current fps is about 0.93. Very high!
Here a video and a frame corrected.

I shooted some videos with the d3200 18-55 lens. To reduce the rolling shutter i preferred to shot at 1280x720p 60fps instead of 1920×1080 25/30 fps.
Less lines to scan for Expeed3 and better video.

To obtain the correct film back (sensor covered by video) i made different tests because the real value is hidden on the nikon site.
I shooted a static video at 18 mm looking at a checkerboard. I needed a method to obtain the width and height of film back.

I set the width to the maximum of the sensor 23.2 mm and I tried to calculate the focal lenght based on accidental perspective. So i had 18 mm confirming the correct width. The height, as a result, was 13.05 mm.

I was afraid if the sensor covered was really the center area (to reuse the distorsion calculated with stills) so i calculated also the distorsion zoom curve for each focal lenght.

Here the shots extracted from the video. All static so no rolling shutter.

Soon some camera tracking clips