| 摘要 |
PROBLEM TO BE SOLVED: To simultaneously attain to arrange a diaphragm device including an ND filter right behind a third lens group for miniaturization and to prevent a ghost caused by the ND filter and an imaging device and having strong intensity from being practically harmful and also to improve the unbalance of a marginal light quantity in an up-and-down direction at a small diaphragming time. SOLUTION: As for a zoom lens 1 which is orderly composed of a first lens group L1 whose position is fixed and that has positive refracting power, a second lens group L2 whose position is movable and that has negative refracting power, a third lens group L3 whose position is fixed and that has the positive refracting power, a fourth lens group L4 whose position is movable and that has the positive refracting power and the imaging device IMG from an object side and in which a nearly afocal system is composed of the first lens group to the third lens group, the diaphragm device 2 including the ND filter is arranged between the third lens group and the fourth lens group, and the diaphragm device including the ND filter is entirely inclined so that one end is shifted on the object side and the other end is shifted on an image surface side.
|
