Zoom lens and camera

A zoom lens comprising:

• a first lens unit having negative optical power, said first lens unit having a negative lens element on a closest side to an object;
• a second lens unit having positive optical power, said second lens unit having two or more positive lens elements and one or more aspheric surfaces;
• a third lens unit having positive optical power;
• and
• a fourth lens unit having positive optical power, said units in the order presented from an object side to an image side,
• wherein at least said second lens unit and said third lens unit are moved toward the object for zooming from a wide angle side to a telephoto side such that a space between said first lens unit and said second lens unit is smaller, a space between said second lens unit and said third lens unit is smaller, and a space between said third lens unit and said fourth lens unit is larger at a telephoto end than at a wide angle end.

A zoom lens comprising:

• a first lens unit having negative optical power, said first lens unit having a negative lens element on a closest side to an object;
• a second lens unit having positive optical power, said second lens unit having two or more positive lens elements;
• a third lens unit having positive optical power, said third lens, unit consisting of one positive lens component;
• and
• a fourth lens unit having positive optical power, said units arranged in the order presented from an object side to an image side,
• wherein at least said second lens unit and said third lens unit are moved toward the object for zooming from a wide angle side to a telephoto side such that a space between said first lens unit and said second lens unit is smaller, a space between said second lens unit arid said third lens unit is smaller, and a space between said third lens unit and said fourth lens unit is larger at a telephoto end than at a wide angle end.

A zoom lens comprising:

• a first lens unit having negative optical power, said first lens unit having two negative lenses adjacent to each other and a positive lens;
• a second lens unit having positive optical power, said second lens unit having one or more aspheric surfaces;
• a third lens unit having positive optical power;
• and
• a fourth lens unit having positive optical power, said units arranged in the order presented from an object side to an image side,
• wherein at least said second lens unit and said third lens unit are moved toward the object for zooming from a wide angle side to a telephoto side such that a space between said first lens unit and said second lens unit is smaller, a space between said second lens unit and said third lens unit is smaller, and a space between said third lens unit and said fourth lens unit is larger at a telephoto end than at a wide angle end.

A zoom lens comprising:

• a first lens unit having negative optical power, said first lens unit having two negative lenses adjacent to each other and a positive lens;
• a second lens unit having positive optical power, said second lens unit having two or more positive lens elements;
• a third lens unit having positive optical power, said third lens unit consisting of one positive lens component;
• and
• a fourth lens unit having positive optical power, said units arranged in the order presented from an object side to an image side,
• wherein at least said second lens unit and said third lens unit are moved toward the object for zooming to a telephoto side from a wide angle side such that a space between said first lens unit and said second lens unit is smaller, a space between said second lens unit and said third lens unit is smaller, and a space between said third lens unit and said fourth lens unit is larger at a telephoto end than at a wide angle end.

A zoom lens comprising:

• a first lens unit having negative optical power;
• a second lens unit having positive optical power, said second lens unit having two or more positive lens elements;
• a third lens unit having positive optical power;
• and
• a fourth lens unit having positive optical power, said units arranged in the order presented from an object side to an image side,
• wherein at least said second lens unit and said third lens unit are moved toward the object for zooming from a wide angle side to a telephoto side such that a space between said first lens unit and said second lens unit is smaller, a space between said second lens unit and said third lens unit is smaller, and a space between said third lens unit and said fourth lens unit is larger at a telephoto end than at a wide angle end, and said zoom lens satisfying the following condition:
• 0.15<√{square root over ((fw×ft))}×<(|1/tkt−1/tkw|)<0.35
• 2.5<ft/fw<4.5
• where fw is a focal length of a total lens system at the wide angle end, ft is a focal length of the total lens system at the telephoto end, tkw is a length from an image plane to an exit pupil at the wide angle end, and tkt is a length from an image plane to an exit pupil at the telephoto end.

A zoom lens comprising:

• a first lens unit having negative optical power, said first lens unit consisting of a negative lens element, a negative lens element, and a positive lens element, said elements arranged in the order presented from an object side to an image side;
• a second lens unit having positive optical power, said second lens unit having two or more positive lens elements and a negative lens element;
• a third lens unit having positive optical power, said third lens unit consisting of one positive lens component;
• and
• a fourth lens unit having positive optical power, said fourth lens unit consisting of one positive lens component, said units arranged in the order presented from the object side to the image side,
• wherein at least said second lens unit and said third lens unit are moved toward the object for zooming from a wide angle side to a telephoto side such that a space between said first lens unit and said second lens unit is smaller, a space between said second lens unit and said third lens unit is smaller, and a space between said third lens unit and said fourth lens unit is larger at a telephoto end than at a wide angle end.

A zoom lens comprising:

• a first lens unit having negative optical power, said first lens unit consisting of having a negative lens element, and a positive lens element, said elements arranged in the order presented from an object side to-an image side;
• a second lens unit having positive optical power, said second lens unit consisting of a first lens subunit having positive optical power and a second lens subunit having positive optical power, with a largest space in said second lens unit therebetween;
• and
• a third lens unit having positive optical power, said units arranged in the order presented from the object side to the image side,
• wherein the lens units are moved for zooming such that a space between said first lens unit and said second lens unit is smaller, and a space between said second lens unit and said third lens unit is larger at a telephoto end than at a wide angle end, said first lens subunit having a first positive lens element, a second positive lens element, and a negative lens element, said elements arranged in the order presented from the object side to the image side, and said zoom lens satisfying the following condition:
• 0.2<d2abW/fw<1.0
• where d2abW is a space between said first lens subunit and said second lens subunit under in-focus on an infinite object at the wide angle end, and fw is a focal length of a total lens system at the wide angle end.

A zoom lens comprising:

• a first lens unit having negative optical power, said first lens unit consisting of a negative lens element with an aspheric surface, and a positive lens element, said elements arranged in the order presented from an object side to an image side;
• and
• a second lens unit having positive optical power, said second lens unit having at least one negative lens element, said units arranged in the order presented from the object side to the image side,
• wherein said second lens unit is moved toward the object for zooming from a wide angle side to a telephoto side such that a space between said first lens unit and said second lens unit is smaller at a telephoto end than at a wide angle end, and said zoom lens satisfying the following condition:
• vd12<22
• where vd12 is an Abbe number of a material of the positive lens element in said first lens unit.

A zoom lens comprising:

• a first lens unit having negative optical power, said first lens unit consisting of a negative lens element and a positive lens element, said elements arranged in the order presented from an object side to an image side;
• a second lens unit having positive optical power, said second lens unit having at least one negative lens element;
• a third lens unit having positive optical power;
• and a fourth lens unit having positive optical power, said units arranged in the order presented from the object side to the image side,
• wherein at least said second lens unit and said third lens unit are moved toward the object for zooming from a wide angle side to a telephoto side such that a space between said first lens unit and said second lens unit is smaller, and a space between said third lens unit and said fourth lens unit is larger at a telephoto end than at a wide angle end, and a space between said second lens unit and said third lens unit changes, and said zoom lens satisfying the following condition:
• Nd11>1.7
• vd11>35
• vd12 <22
• where Nd11 is a refractive index of a material of the negative lens element in said first lens unit, vd11 is an Abbe number thereof, and vd12 is an Abbe number of a material of the positive lens element in said first lens element.