Showing papers on "Apochromat published in 1968"
TL;DR: Methods for the construction and synthesis of large-aperture, weak, cross cylinder lenses and segments thereof are given, and a sensitive test for lateral chromatic aberration is included in an appendix.
Abstract: Two methods are described for testing cameras and camera lenses by utilizing the properties of the crossed cylinder lens, an ophthalmic test device. In the first, the cylinder lens is used in conjunction with a rectangular grid to defocus the star image formed by a collimator. This test permits quantitative determination of axial chromatic aberration, spherical aberration and its variations with wavelength, and coma of the lens. In the second, a segment of the cylinder lens is used as a supplementary lens attachment to the camera, which photographs a polar coordinate chart. Analysis of the photograph permits determination of the sagittal and tangential field curvatures, and also indicates errors in focal adjustment and misalignment of film plane with respect to the lens axis. Since these tests require cylinder lenses of smaller dioptric power and quality superior to that available from the ophthalmic lens industry, methods for the construction and synthesis of large-aperture, weak, cross cylinder lenses and segments thereof are given. Experimental details of the lens testing procedures, together with examples of photographic determination of the various camera and lens defects, are presented. A sensitive test for lateral chromatic aberration is included in an appendix.
29 citations
TL;DR: In this paper, the dependence of the spherical aberration coefficient Cs on object position z0 and magnification M is studied using Glaser's bell-shaped field model, where Cs may be written in the forms IMG1 where ai and bi are functions of the lens excitation k2.
Abstract: The dependence of the spherical aberration coefficient Cs on object position z0 and magnification M is studied using Glaser's bell-shaped field model. It is shown that Cs may be written in the forms IMG1 where ai and bi are functions of the lens excitation k2. ai and bi are tabulated for a range of values of k2.
7 citations
Patent•
27 Mar 1968
TL;DR: In this article, an ADAPTER LENS system is mounted on the front of a PHOTOGRAPHIC OBJECT LENS HAVING a FOCAL LENGTH BETWEEN 135 MM.
Abstract: AS ADAPTER LENS SYSTEM IS MOUNTED ON THE FRONT OF A PHOTOGRAPHIC OBJECT LENS HAVING A FOCAL LENGTH BETWEEN 135 MM. AND 300 MM. AND INCLUDES A FLUORITE LENS OF A FOCAL LENGTH BETWEEN 350 MM. AND 500 MM. AND A NEGATIVE LENS OF GREATER REFRACTIVE INDEX, THE ADAPTER LENS SYSTEM HAVING A FOCAL LENGTH OF INFINITY. THE ADAPTER LENS REDUCES CHROMATIC ABERRATION OF THE LENS SYSTEM IN THE INFRARED RANGE.
4 citations