Wide angle zoom lens

Abstract

Abstract PURPOSE:To obtain a wide angle zoom lens which has a less filter diameter and aberrations compensated excellently by specifying conditions of a lens system consisting of the 1st group with negative refracting power and the 2nd group with positive refracting power as a variable magnification system and the 3rd group as a relay lens system successively from an object side. CONSTITUTION:With regard to a zoom lens which consists of a variable magnification system of the 1st group with negative refracting power and the 2nd group of positive refracting power and a relay lens system of the 3rd group and allows the 2nd group to move on the optical axis for magnification variation while associating the 1st group with the 2nd group to hold the focal point constant, inequalities (1) and (2) hold, where beta2t is the lateral magnification of the 2nd group and beta3 is the lateral magnification of the 3rd group. Inequality (1) relates to the balance between absorption correction and a filter diameter. Inequality (2) relates to the balance between the filter diameter and brightness. Thus, a wide angle zoom lens which has a less filter diameter and aberrations compensated excellently is obtained.

Inventors

• 👤 Yusuke Nanjo
• 👤 南條　雄介

Bibliographic Details