Modified Petzval lens with aperture greater than f 1.2 - has positive doublets, positive meniscus lens and divergent lens (NL 25.7.77)

摘要

Modified Petzval lens has two positive doublet, positive meniscus lens and divergent lens. The aperture is greater than f/1.2. The diffraction indices of the positive elements are greater than 1.65 and those of the negative parts of the two doublets are greater than 1.8. The distance between the meniscus lens and the second doublet is equal to 0.60 to 0.75 x f. The sum of the thicknesses of individual lenses and air gaps is smaller than 1.5 x f. The specification comprises max. deviations for each curvature radius (gamma1 to gamma12), each thickness (d1 to d11) and distance, each diffraction index and each square root of a value.