Patent ID: 7486450
Filing Date: 2009-02-03
Classification: G02B,H04N

Abstract:
1. A lens system comprising, sequentially in that order from a magnifying side, a first lens group which makes up a substantially afocal optical system as a whole and a second lens group having a positive refractive power as a whole, the first lens group being configured to comprise, sequentially in that order from a magnifying side, a first sub-lens group or 1 a lens group having a negative refractive power as a whole and a second sub-lens group or 1 b lens group having a positive refractive power as a whole, the second lens group being configured to comprise, sequentially in that order from a magnifying side, a first sub-lens group or 2 a lens group having a negative refractive power as a whole and a second sub-lens group or 2 b lens group having a positive refractive power as a whole, wherein, the following conditional expression (1) is satisfied with respect to a power set for the first lens group, the following conditional expression (2) is satisfied with respect to an afocal magnification set for the first lens group, the following conditional expression (3) is satisfied with respect to a power set for the 1 a lens group, the following conditional expression (4) is satisfied with respect to a power set for the 2 a lens group, the following conditional expression (5) is satisfied with respect to a power set for the 2 b lens group, and the following conditional expression (6) is satisfied with respect to a thickness dimension at an optical axis of the first lens group; where, f: Composite focal length of the whole lens system; f h h f f f T