| 摘要 |
PROBLEM TO BE SOLVED: To provide a fish-eye lens that has a small F-number and compact size, is wide-angle and suitable for video shooting, and offers good AF and optical performance.SOLUTION: A fish-eye lens comprises a first lens group G1 having negative refractive power, a second lens group G2 having positive refractive power, and a third lens group G3 having positive refractive power in order from the object side, where the first lens group G1 comprises a first N1 lens group G1N1 having negative refractive power and a first N2 lens group G1N2 having negative refractive power in order from the object side. The first N1 lens group G1N1 comprises, in order from the object side, a first negative meniscus lens L1N1 having a convex surface on the object side, and a second negative meniscus lens L2N1 having a convex surface on the object side, while the first N2 lens group G1N2 comprises a negative lens L3N2 having a concave surface on the object side. When shifting focus from an object at infinity to an object at a short distance, the first lens group G1 and the third lens group G3 are stationary relative to an image plane, while the second lens group G2 moves toward the image side.SELECTED DRAWING: Figure 1 |
