Optical imaging system

摘要

An optical imaging system with seven uncemented elements, of which numbers 1, 2, 5, 6, 7 have positive refractive powers and numbers 3, 4 have negative refractive powers; the specific choice of refractive indices results in a very good imaging performance (image formation efficiency) and in the possibility of setting the field curvature by setting the refractive index of the material of the first element, in which case, in particular when it is designed as projection objective, the field curvature is set in such a manner that a curvature of the film image, occurring during the projection of a film, in particular a 70 mm cine film is compensated.