Zoom lens and image pickup apparatus
Provided is a zoom lens including in order from an object side: a positive first lens unit not moving for a change in magnification; a negative second lens unit moving for a change in magnification; and two or three rear lens units having a positive refractive power as a whole, at least one of the rear lens units being configured to move for a change in magnification. The first lens unit includes a negative first lens sub-unit not moving for focusing, a positive second lens sub-unit moving for focusing, a third lens sub-unit not moving for focusing, and a positive fourth lens sub-unit moving for focusing. An amount of movement of the second lens sub-unit during focusing from infinity to a minimum object distance, and an amount of movement of the fourth lens sub-unit during focusing from infinity to the minimum object distance satisfy a specific conditional expression.
1. A zoom lens comprising in order from an object side to an image side:
a first lens unit having a positive refractive power and configured not to move for a change in magnification of the zoom lens;
a second lens unit having a negative refractive power and configured to move for a change in magnification of the zoom lens; and
two or three rear lens units having a positive refractive power as a whole, at least one of the two or three rear lens units being configured to move for a change in magnification of the zoom lens,
wherein an interval between lens units in each pair of adjacent two lens units is changed for a change in magnification of the zoom lens,
wherein the first lens unit includes a first lens sub-unit having a negative refractive power and configured not to move for focusing of the zoom lens, a second lens sub-unit having a positive refractive power and configured to move for focusing of the zoom lens, a third lens sub-unit configured not to move for focusing of the zoom lens, and a fourth lens sub-unit having a positive refractive power, and configured to move for focusing of the zoom lens, and
wherein the following conditional expression is satisfied:
−10.0< M 12/ M 14<−0.1,
where M12 represents an amount of movement of the second lens sub-unit for focusing of the zoom lens from infinity to a minimum object distance, and M14 represents an amount of movement of the fourth lens sub-unit for focusing of the zoom lens from infinity to the minimum object distance.
2. The zoom lens according to claim 1 , wherein the first lens unit includes a fifth lens sub-unit having a positive refractive power and configured to move for focusing of the zoom lens.
3. The zoom lens according to claim 1 , wherein the following conditional expression is satisfied:
−1.5< F 11/ F 12<−0.5,
where F11 represents a focal length of the first lens sub-unit, and F12 represents a focal length of the second lens sub-unit.
4. The zoom lens according to claim 1 , wherein the following conditional expression is satisfied:
1.0< F 14/ F 1<2.0,
where F1 represents a focal length of the first lens unit, and F14 represents a focal length of the fourth lens sub-unit.
5. The zoom lens according to claim 1 ,
wherein the third lens sub-unit includes a positive lens and a negative lens, and
wherein the following conditional expression is satisfied:
50.0<ν dP 13−ν dN 13<78.0,
where νdP13 represents an average abbe number of a positive lens included in the third lens sub-unit, and νdN13 represents an average abbe number of a negative lens included in the third lens sub-unit.
6. The zoom lens according to claim 1 , wherein the following conditional expression is satisfied:
−10.0< F 1/ F 2<−2.0,
where F1 represents a focal length of the first lens sub-unit, and F2 represents a focal length of the second lens sub-unit.
7. The zoom lens according to claim 1 ,
wherein the second lens sub-unit consists of one positive lens, and
wherein the following conditional expression is satisfied:
50.0<ν dP 12<95.1,
where νdP12 represents an abbe number of the one positive lens.
8. The zoom lens according to claim 7 , wherein the one positive lens has an aspherical surface.
9. The zoom lens according to claim 1 ,
wherein the first lens sub-unit includes a positive lens and a negative lens, and
wherein the following conditional expression is satisfied:
−40.0<ν dP 11−ν dN 11<−10.0,
where νdP11 represents an average abbe number of the positive lens included in the first lens sub-unit, and νdN11 represents an average abbe number of the negative lens included in the first lens sub-unit.
10. An image pickup apparatus comprising:
a zoom lens comprising in order from an object side to an image side:
a first lens unit having a positive refractive power and configured not to move for a change in magnification of the zoom lens;
a second lens unit having a negative refractive power and configured to move for a change in magnification of the zoom lens; and
two or three rear lens units having a positive refractive power as a whole, at least one of the two or three rear lens units being configured to move for a change in magnification of the zoom lens,
wherein an interval between lens units in each pair of adjacent two lens units is changed for a change in magnification of the zoom lens,
wherein the first lens unit includes a first lens sub-unit having a negative refractive power and configured not to move for focusing of the zoom lens, a second lens sub-unit having a positive refractive power and configured to move for focusing of the zoom lens, a third lens sub-unit configured not to move for focusing of the zoom lens, and a fourth lens sub-unit having a positive refractive power and configured to move for focusing of the zoom lens, and
wherein the following conditional expression is satisfied:
−10.0< M 12/ M 14<−0.1,
where M12 represents an amount of movement of the second lens sub-unit for focusing of the zoom lens from infinity to a minimum object distance, and M14 represents an amount of movement of the fourth lens sub-unit for focusing of the zoom lens from infinity to the minimum object distance; and
an image pickup element configured to pick up an image formed by the zoom lens.