VARIABLE FOCAL DISTANCE OBJECTIVE WITH THREE GROUPS OF LENSES Russian patent published in 2000 - IPC

FIELD: photography. SUBSTANCE: proposed objective has three groups of positive lenses. Lenses of first group are cemented together and include positive lens and negative meniscus facing object with concavity. Second groups of lenses is made of two plano-convex lenses and biconvex lens placed between them. Third group of lenses has first and second lenses manufactured in the form of positive and negative meniscuses facing image with concavity, third lens in the form of negative meniscus facing object with concavity and fourth and fifth lenses made in the form of positive meniscuses facing correspondingly object and image with concavity. EFFECT: design of objective with expanded application field thanks to forward removal of exit pupil and increased informativity of it due to enlargement of angular field of objective. 3 dwg, 4 tbl