Zoom lens and imaging apparatus including the same

An imaging apparatus comprising:

• a zoom lens including, in order from an object side to an image side:
• a first lens unit having positive refractive power;
• a second lens unit having negative refractive power;
• a third lens unit having positive refractive power;
• and
• a fourth lens unit having positive refractive power,
• wherein, during zooming from a wide-angleend to a telephoto end, the first lens unit does not move and at least the second lens unit and the fourth lens unit move, and a distance between adjacent lens units varies during zooming,
• wherein the first lens unit includes, in order from the object side to the image side thereof, a negative lens, a positive lens, a positive lens, and a positive lens, and the second lens unit includes three or more lens elements including at least one positive lens,
• wherein one of the positive lenses included in the first lens unit satisfies a following conditional expression:
• 74.0<νd1p<100.0,
• wherein the second lens unit includes a positive lens that satisfies a following conditional expression:
• 10.0<νd2p<21.0,
• where Abbe number of a material of the one positive lens included in the first lens unit is denoted by νd1p and Abbe number of a material of the positive lens provided in the second lens unit is denoted by νd2p, and \
• wherein following conditional expressions are satisfied:
• −7.30<f1/f2<−4.60,
• 1.16<f3/f4<1.55,
• 3.80<f4/fw<6.50,
• 0.95<(TL/Φt)/(ft/fw)<1.20, and
• −12.00<B2t<−5.80,
• where a focal length of the first lens unit is denoted by f1, a focal length of the second lens unit is denoted by f2, a focal length of the third lens unit is denoted by f3, a focal length of the fourth lens unit is denoted by f4, a focal length of an entire system at the wide-angle end is denoted by fw, and a lateral magnification of the second lens unit during focusing on an infinite-distance object at the telephoto end is denoted by β2t, a distance on an optical axis from a lens surface closest to the object side in the first lens unit to an image plane is denoted by TL, an effective image circle radius at the telephoto end is denoted by Φ, and a focal length of the entire system at the telephoto end is denoted by ft;
• and
• an image pickup element configured to receive an image formed by the zoom lens.