title: Focusing Criterion for Ground-Glass-Focused Lenses, Derived from MTF Measurements.
abstract: Lenses used in the graphic arts and in professional photography generally are focused on a ground-glass screen. In order to obtain a mathematically defined focusing criterion, a sector star target was visually focused on a ground glass through several of these lenses and the MTF curves measured at various receiving planes. It was found that in the frequency range between 15 cycles/mm and 30 cycles/mm the visual receiving plane gives higher MTF values than in any other plane. The corresponding contrast values were found to lie between 0.3 and 0.5.
authors.forename: P
authors.initials: P
authors.lastname: Kuttner