| 摘要 |
PURPOSE:To simplify the structure of a lens barrel and to compensate excellently aberration variation during focusing by arranging a focusing lens group and a fixed lens group at the image plane side of a lens group for power variation, and performing focusing operation through the focusing lens group. CONSTITUTION:The lens group IV and fixed lens V are arranged successively; at the image-plane side of lens groups I, II, and III for power variation and the respective lenses I, II, III, IV, and V are so constituted that even if only the lens groups I, II, and III are moved for power variation when the focusing lens group IV is focused on a short-distance object, the image-plane position of the whole system is held at a constant position. |
