And I also think your math is wrong.

Based on when I turn on raw video, the max res I can get is 1728x972 (in terms of setting not recording), and that takes up the entire screen, so it wouldn't be based on 1920x1080, this is from a 550D pov.

And additionally on top of that, 1080 would be the wrong height to measure from as you can use the whole 3:2 field.

Which also note, the project-able area of a lens does not change by width as it does my height, it projects a circle, so the same max res you can get of the width will be the same as the height. What makes a picture rectangle is either the sensor size or a gate blocking it, which is still part of the camera, not part of the lens.

Super16 = 7.41 mm by 12.52 mm = diagonal is ~14.54mm

ASP-C = 22.20 mm by 14.80 mm = diagonal is ~26.68mm

Diagonal is the widest projection of the image, this can be projected all around, as the projection is circle.

Basic trig states that the diagonal of a right angle triangle is: A^2 + B^2 = C^2

Super16 is a 1.835 crop of ASPC: (actually 1.834938102x)

The full frame of Raw mode (at least for 550D) is 1728x1152 at 3:2.

And again, the width of the project-able area of the lens will be the same as the height and will be the same as the diagonal.

Basing the crop from the width the raw res would be 940x940.

But when I think of that I think I have done it wrong because the diagonal is larger which means more pixels would surely fit...

Maybe I have stuffed up completely.