Notation according to DIN 1335 and DIN 4522:
Focal length | f ', F' | |
Front focal length | SF | |
Back focal length | S'F' | |
Principal point / Nodal point separation | HH ' | (+)
Front nodal point is to the left of the rear nodal point (-) Front nodal point is to the right of the rear nodal point |
Pupil magnification | ß'P | Diameter of exit pupil / Diameter of entrance pupil |
Entrance pupil Position | Sep | Distance from Front Glass Vertex to Entrance Pupil |
Exit pupil position | S'ap | Distance from Rear Glass Vertex to Exit Pupil |
Overall optical length | Σd | Distance from front vertex of first lens to rear vertex of last lens |
Image to Object distance | OO' | Total length from image plane to object plane |
Magnification ratio | ß' | u'/u |
Object Height | u | 1/2 actual object height |
Image Height | u' | 1/2 actual image height |
*All distances are measured from left to right.