Quote Originally Posted by Alan Klein View Post
Greg: If lens movements change falloffs with center filter masks, are there falloffs with regular lenses, let's say 150mm, if you use movements or for that matter when you use center filters on 75mm lenses?
PMFJI. Alan, movements increase the angle between the lens' axis and the edges and corners of the gate. The larger the angle, the worse the falloff. This is true for all lenses.

Center filters don't cause falloff, they approximately correct it by being denser at the center than at the edge.