Patent ID: 7336304
Filing Date: 2008-02-26
Classification: G02B

Abstract:
1. A zoom lens of two elements, which comprises a front elements lens having a negative refractivity and a rear elements lens having a positive refractivity in sequence from an object side, in which an object of an arbitrary distance between infinite-point and a predetermined closest distance is formed on an imaging plane, wherein a track of the front elements by zooming is set up so that the front elements are disposed at a position that formula set forth below is satisfied: where a length from a top of the front elements on an optical axis to a front side main point of the front elements: Ha a main point interval of the front elements: HH a length from a rear side main point of the front elements to a front side main point of the rear elements where an air conversion is carried out on an optical member not included in the front elements and the rear elements: L, a main point interval of the rear elements: HH a focal length of the front elements: f a focal length of the rear elements: f a length from the object at the time of near photography to the front side main point of the front elements where the air conversion is carried out on the optical member not included in the front elements: m, and a length from the top of the front elements on the optical axis to the imaging plane where the air conversion is carried out on the optical member not included in the front elements and the rear elements: T