| 摘要 |
A zoom lens includes in order from an object side, a first lens unit having a negative refractive power, a second lens unit having a positive refractive power, and a third lens unit having a negative refractive power, and at the time of zooming, movement of the first lens unit includes at least a movement toward an image side, the second lens unit moves integrally with an aperture stop, and the third lens unit moves toward the object side, and the first lens unit includes at least a negative lens and a positive lens, and the negative lens is disposed nearest to an object, and the following conditional expressions are satisfied:;0.75<(β2t/β2w)/(β3t/β3w)<1.38;−0.70<β2w<−0.32;0.96<f2/fw<1.80. |
| 主权项 |
1. A zoom lens comprising in order from an object side:
a first lens unit having a negative refractive power; a second lens unit having a positive refractive power; and a third lens unit having a negative refractive power, wherein the total number of lens units in the zoom lens is three, and at the time of zooming, all distances between the lens units change, and at the time of zooming, movement of the first lens unit includes at least a movement toward an image side, the second lens unit moves integrally with an aperture stop, and the third lens unit moves toward the object side, and the movement of the first lens unit toward the image side is a movement when the zooming started from a wide angle end, and the movement of the third lens unit toward the object side is a movement at the time of zooming from the wide angle end to a telephoto end, and the first lens unit includes at least a negative lens and a positive lens, and the negative lens is disposed nearest to an object, and the following conditional expressions are satisfied:
0.75<(β2t/β2w)/(β3t/β3w)<1.38−0.70<β2w<−0.320.96<f2/fw<1.80.1.00<Daiw/(tan ωt×ft)<2.90 where, β2t denotes a lateral magnification of the second lens unit at the telephoto end, β2w denotes a lateral magnification of the second lens unit at the wide angle end, β3t denotes a lateral magnification of the third lens unit at the telephoto end, and β3w denotes a lateral magnification of the third lens unit at the wide angle end, here, each lateral magnification is a lateral magnification at the time of focusing on an infinite object point, and f2 denotes a focal length of the second lens unit, fw denotes a focal length of the overall zoom lens system at the wide angle end, Daiw denotes a distance between the aperture stop and an image plane at the wide angle end, ωt denotes a half angle of view at the telephoto end, and ft denotes a focal length of the overall zoom lens system at the telephoto end. |
