Flat Fielding Without Filling the Frame

This feature would allow the user to map and correct the falloff of light without the requirement to fill the entire capture area with reference material such as gray board. For example allowing an even field to be generated by moving a board that doesn't fill the frame to different positions in the frame, or even by using a light meter to manually measure the light at a series of points in the frame. This would assist with even fielding in scenes where it is impractical or impossible to fill the entire capture area with reference material.