Greatly variable magnification zoom lens system of large aperture ratio

摘要

Attention has been directed to the fact that in zoom objective lens systems, the compensator for compensating the focal point shift caused by the zoom movement of the variator has generally two solution curves. A novel zooming mechanism such that the compensator is transferred from one to the other solution curve in the middle position of the zooming is employed in a zoom lens system to which this invention relates. As a result, this permits the variator and compensator to partake equally the function on magnification variation to enable minimizing the image shift sensitivity of each movable lens group and making the diameter of the front lens element small, and moreover compensating the variation of aberrations to very good degree.