Uli Plank wrote:As much as I honour your knowledge in all things cinematography, John, in this case I dare to contradict.
Having done a lot of panoramic photography (and using one of those expensive rigs) the nodal point was always somewhere in the lens and we had to test it out for each lens individually.
It should be something like the point where the rays are crossing, isn't it?
But while we were using more expensive ones due to vertical mounting of the camera, a cheap mount for moving the camera back and forth with some sort of scale should suffice to find that point. That is, if you can make sure to have the lens centered over the mounting point laterally.
The quick version is I was wrong, it is NOT the film plane, but it also seems there can be more than one nodal point.
"Two additional cardinal points are the front and rear nodal points (N and N′) that define the location of unit angular magnification for a focal system."
https://spie.org/publications/fg01_p11_ ... ints?SSO=1I think though that in most functions for shooting product and drama, the film plane can be considered "close enough" depending on what you're trying to do of course. I feel like I've used nodal head before and the assumed nodal position was the film plane.
Many times we use "nodal" heads like an Arri geared head or something like a Ronford F7 and these usually function by having the film / sensor plane itself be the nodal point around which the camera moves.
Most grips would set these heads up assuming the film plane was the nodal point.
https://www.cartoni.com/products/fluid- ... lambda-50/http://www.ronfordbaker.co.uk/products/ ... s/atlas-7/If you were trying to shoot stills with panoramic stitching for example, then it might require the true precision of the lens nodal point.
JB