Zoom lens and image pickup apparatus including the same

摘要

A zoom lens includes, in order from an object side: a first positive lens unit not moving for zooming; a second negative lens unit moving during zooming; a third positive lens unit moving during zooming; a fourth positive lens unit moving during zooming; and a fifth positive lens unit not moving for zooming. Each of the lens units includes positive and negative lenses, and satisfies 10<νp−νn<54, −1<β2w<−0.05, −5<β2t<−1, and −1<β34z2<−0.3, where νp is average Abbe constant of the positive lens of the fourth unit, νn an average Abbe constant of the negative lens of the fourth unit, β2w a magnification of the second unit at wide angle end, β2t a magnification of the second unit at telephoto end, and β34z2 a magnification of a combined lens unit including the third and fourth unit at a zoom position where the magnification of the second unit is −1.

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 which does not move for zooming; a second lens unit having a negative refractive power which moves during zooming; a third lens unit having the positive refractive power which moves during zooming; a fourth lens unit having the positive refractive power which moves during zooming; and a fifth lens unit having the positive refractive power which does not move for zooming, wherein each of the first lens unit to the fifth lens unit includes at least one positive lens and at least one negative lens, and wherein the following conditional expressions are satisfied:
−10<νp−νn<54;−1<β2w<−0.05;−5<β2t<−1;and−1<β34z2<−0.3, where νp is an average Abbe constant of the at least one positive lens of the fourth lens unit, νn is an average Abbe constant of the at least one negative lens of the fourth lens unit, β2w is an imaging magnification of the second lens unit at a wide angle end, β2t is an imaging magnification of the second lens unit at a telephoto end, and β34z2 is an imaging magnification of a combined lens unit including the third lens unit and the fourth lens unit at a zoom position z2 where the imaging magnification of the second lens unit is −1.