Zoom lens and image pickup apparatus using the same

A zoom lens comprising, in order from an object side to an image side:

• a front unit having a negative refractive power;
• and
• a rear unit having a positive refractive power, which includes an aperture stop,
• wherein:
• the front unit includes a first lens having a negative refractive power, a second lens having a negative refractive power, and a third lens having a positive refractive power,
• the first lens is disposed nearest to an object, and has a meniscus shape of which a convex surface is directed toward the object side,
• the second lens is disposed on the image side of the first lens, and has a meniscus shape of which a convex surface is directed toward the object side,
• the rear unit includes, in order from the object side to the image side, a first lens unit A and a second lens unit B,
• at a time of zooming from a wide angle end to a telephoto end, a distance between the front unit and the rear unit narrows, and a distance between the first lens unit A and the second lens unit B changes,
• the first lens unit A includes, in order from the object side to the image side, a first sub-lens unit having a positive refractive power, the aperture stop, and a second sub-lens unit,
• the second sub-lens unit includes a focusing lens unit,
• at a time of focusing, only the focusing lens unit moves along an optical axis,
• at the time of zooming, a distance between the first sub-lens unit and the second sub-lens unit changes, and
• the following conditional expression is satisfied:
• 1.25<fRw/FBw<5,
• where,
• fRw denotes a focal length of the rear unit at the wide angle end, and
• FBw denotes a back focus at the wide angle end.

A zoom lens comprising, in order from an object side to an image side:

• a front unit having a negative refractive power;
• and
• a rear unit having a positive refractive power, which includes an aperture stop,
• wherein:
• the front unit includes a first lens having a negative refractive power, a second lens having a negative refractive power, and a third lens having a positive refractive power,
• the first lens is disposed nearest to an object, and has a meniscus shape of which a convex surface is directed toward the object side,
• the second lens is disposed on the image side of the first lens, and has a meniscus shape of which a convex surface is directed toward the object side,
• the rear unit includes, in order from the object side to the image side, a first lens unit A and a second lens unit B,
• at a time of zooming from a wide angle end to a telephoto end, a distance between the front unit and the rear unit narrows, and a distance between the first lens unit A and the second lens unit B changes,
• the first lens unit A includes, in order from the object side to the image side, a first sub-lens unit having a positive refractive power, the aperture stop, and a second sub-lens unit,
• the second sub-lens unit includes a focusing lens unit,
• at a time of focusing, only the focusing lens unit moves along an optical axis,
• at the time of zooming, a distance between the first sub-lens unit and the second sub-lens unit changes, and
• the following conditional expression is satisfied:
• −25<DTLw<7,
• where,
• DTLw denotes a distortion at a maximum angle of view at the wide angle end, and is expressed by DTLw=(IHw1−IHw2)/IHw2×100(%), and here
• IHw1 denotes an actual image height of an image formed on an image plane by the maximum angle of view at the wide angle end from an infinite object point, and
• IHw2 denotes a paraxial image height of an image formed on the image plane by the maximum angle of view at the wide angle end from the infinite object point.