Copying lens for microfilm photography

A new lens design for precise copying exemplifies the success of the rms error function as a suitable criterion for the design of high resolution lenses. The design, a 145-mm f/4.0, gives 400-line/mm, high contrast,white-light visual resolution throughout a 30-mm flat image when used at 20:1 conjugates. On high resolution plates, a resolution of 320 lines/mm is obtained. The five-glass design has no vignetting of the marginal beams, presents no manufacturing problems, and gave full resolution when first assembled. The prescriptionwas found by the LASL 1972 Lens Design Program.