(a) Field of the Invention
The present invention relates to a photographic lens system having an angle of image approximately 43.degree. , and aperture ratio of 1 : 1.2 and a back focal distance nearly as long as 70% o f the total focal distance of the entire lens system.
(B) Description of the prior art
In order to obtain a variant Gauss type photographic lens system having a large aperture ratio and a long back focal distance, it is generally required to appropriately modify the symmetry of the front and rear lens groups with regard to a stop while making use of the merits resulting from the symmetry.
USPTO Backgrounds
USPTO Backgrounds