Optical objectives

Claim 1

AN OPTICAL OBJECTIVE OF THE INVERTED TELEPHOTO TYPE CORRECTED FOR SPHERICAL AND CHROMATIC ABERRATIONS, COMA, ASTIGMATISM, FIELD CURVATURE AND DISTORTION, COMPRISING A DIVERGENT FRONT MEMBER THE NUMERICAL VALUE OF WHOSE EQUIVALENT FOCAL LENGTH LIES BETWEEN 2.5F AND 5F WHERE F IS THE EQUIVALENT FOCAL LENGTH OF THE COMPLETE OBJECTIVE, AND A CONVERGENT REAR MEMBER, WHOSE EQUIVALENT FOCAL LENGTH FR LIES BETWEEN .8F AND 1.4F, SEPARATED FROM THE FRONT MEMBER BY AN AIR SPACE WHOSE AXIAL LENGTH LIES BETWEEN .8F AND 1.4F, THE CONVERGENT REAR MEMBER COMPRISING A SIMPLE CONVERGENT MENISCUS FIRST COMPONENT HAVING ITS SURFACES CONVEX TO THE FRONT, A CONVERGENT DOUBLET SECOND COMPONENT BEHIND THE FIRST COMPONENT, A SIMPLE BICONCAVE DIVERGENT THIRD COMPONENT BEHIND THE SECOND COMPONENT, A CONVERGENT DOUBLET FOURTH COMPONENT BEHIND THE THIRD COMPONENT, AND A DIAPHRAGM LOCATED BETWEEN THE THIRD AND FOURTH COMPONENTS, THE AXIAL AIR SEPARATIONS BETWEEN THE SECOND AND THIRD COMPONENTS AND BETWEEN THE THIRD AND FOURTH COMPONENTS OF THE REAR MEMBER LYING RESPECTIVELY BETWEEN .04FR AND .055FR AND BETWEEN .075FR AND .2FR, WHILST THE RADIUS OF CURVATURE OF THE FRONT SURFACE OF THE DIVERGENT THIRD COMPONENT OF THE REAR MEMBER LIES BETWEEN .75FR AND 1.45FR AND IS LESS THAN ONE-SIXTH OF THAT OF THE REAR SURFACE OF THE DOUBLET SECOND COMPONENT OF THE REAR MEMBER, THE MEAN REFRACTIVE INDEX OF THE MATERIAL OF THE REAR ELEMENT OF THE DOUBLET FOURTH COMPONENT OF THE REAR MEMBER EXCEEDING THAT OF THE FRONT ELEMENT THEREOF BY BETWEEN .025 AND .075.