Zoom lens and image pickup apparatus using the same

摘要

A zoom lens includes a first lens unit having a positive refractive power, a second lens unit having a negative refractive power, third lens unit having a positive refractive power, a fourth lens unit having a negative refractive power, a fifth lens unit having a positive refractive power, and an aperture stop disposed between the second lens unit and the third lens unit. At the time of zooming, the aperture stop moves and the fifth lens unit is fixed. At the time of zooming from a wide angle end to a telephoto end, a distance between the first lens unit and the second lens unit widens, a distance between the second lens unit and the third lens unit narrows, a distance between the third lens unit and the fourth lens unit fluctuates, and a distance between the fourth lens unit and the fifth lens unit fluctuates.

主权项

1. A zoom lens comprising in order from an object side to an image side:
a first lens unit having a positive refractive power; a second lens unit having a negative refractive power; a third lens unit having a positive refractive power; a fourth lens unit having a negative refractive power; and a fifth lens unit having a positive refractive power, wherein the zoom lens has an aperture stop, which is disposed between a surface nearest to an image plane side of the second lens unit and a surface nearest to the image plane side of the third lens unit, and the second lens unit has a negative lens, wherein the negative lens is a single lens, and the negative lens is disposed nearest to the image plane side within the second lens unit, and the third lens unit has a lens having a convex surface directed toward the image plane side, which is disposed nearest to the image plane side within the third lens unit, and total number of lenses in the third lens unit is at most four, and the fifth lens unit has a lens having a convex surface directed toward the image plane side, which is disposed nearest to the image plane side within the fifth lens unit, and at the time of zooming, the aperture stop moves together with the third lens unit, and the fifth lens unit is fixed, and at the time of zooming from a wide angle end to a telephoto end, a distance between the first lens unit and the second lens unit widens, a distance between the second lens unit and the third lens unit narrows, a distance between the third lens unit and the fourth lens unit fluctuates, and a distance between the fourth lens unit and the fifth lens unit fluctuates, and the following conditional expression (4) is satisfied:
0.9