Cardinal Planes

The term cardinal planes refers to those special conjugate positions where the object and image surfaces have a specific magnification. The point where the plane intersects the optical axis is the cardinal point corresponding to that cardinal plane. The cardinal planes include the principal planes, where the lateral magnification is +1, the anti-principal planes, where the lateral magnification is -1, the nodal planes, where the angular magnification is +1, the anti-nodal planes, where the angular magnification is -1, and the focal planes, where the magnification is 0 for the image space focal plane and infinite for the object space focal plane.

Except for the focal planes, the cardinal planes are conjugates with each other, that is, the image space principal plane is conjugate with the object space principal plane, etc. If the lens has the same index in both object space and image space, the nodal planes are identical to the principal planes.

OpticStudio lists the distance from the image surface to the various image space planes, and lists the distance from the first surface to the various object space planes.