Zoom optical system and camera using the same

A zoom optical system comprising a lens system, said lens system consisting of, in order from an object side:

• a first lens unit having a positive refracting power;
• and
• a second lens unit having a negative refracting power,
• in variable magnification change from a wide-angle end position through a telephoto end position, each of said first lens unit and said second lens unit being moved toward the object side in such a manner that a space between said first lens unit and said second lens unit decreases,
• wherein said first lens unit consists of, in order from the object side, a first lens component having a positive refracting power, a second lens component having a negative refracting power, and a third lens component having a positive refracting power, said third lens component consisting of one cemented-lens component,
• wherein said second lens unit comprises at least one positive lens element and two negative lens elements, one of said negative lens elements being a negative meniscus lens that is disposed on a most image side with a convex surface thereof being directed toward an image side, and
• wherein the following conditions are satisfied:
• LT/fT<0.85
• 1.67<NL23
• where LT is a total length of the entire zoom optical system in the telephoto end position, fT is a focal length of the entire zoom optical system in the telephoto end position, and NL23 is a refractive index of said negative lens element disposed on the most image side in said second lens unit.

A zoom optical system comprising a lens system, said lens system consisting of, in order from an object side:

• a first lens unit having a positive refracting power;
• and
• a second lens unit having a negative refracting power,
• in variable magnification change from a wide-angle end position through a telephoto end position, each of said first lens unit and said second lens unit being moved toward the object side in such a manner that a space between said first lens unit and said second lens unit decreases,
• wherein said first lens unit consists of, in order from the object side, a first lens component having a positive refracting power, a second lens component having a negative refracting power, and a third lens component having a positive refracting power, said third lens component having at least one negative lens element, and
• wherein said second lens unit consists of, in order from the object side, a lens element having a negative refracting power, a lens element having a positive refracting power, and a lens element having a negative refracting power.

A zoom optical system comprising a lens system, said lens system consisting of, in order from an object side:

• a first lens unit having a positive refracting power;
• and
• a second lens unit having a negative refracting power,
• in variable magnification change from a wide-angle end position through a telephoto end position, each of said first lens unit and said second lens unit being moved toward the object side in such a manner that a space between said first lens unit and said second lens unit decreases,
• wherein said first lens unit consists of, in order from the object side, a first lens component having a positive refracting power, a second lens component having a negative refracting power, and a third lens component having a positive refracting power, said third lens component consisting of one cemented-lens component, and
• wherein said second lens unit consists of, in order from the object side, a lens element (L21) having a negative refracting power and a lens element (L22) having a negative refracting power, said lens element (L21) having at least one aspherical surface.

A zoom optical system comprising a lens system, said lens system consisting of, in order from an object side:

• a first lens unit having a positive refracting power;
• and
• a second lens unit having a negative refracting power,
• in variable magnification change from a wide-angle end position through a telephoto end position, each of said first lens unit and said second lens unit being moved toward the object side in such a manner that a space between said first lens unit and said second lens unit decreases,
• wherein said first lens unit consists of, in order from the object side:
• a single-lens component consisting of a lens element (L11) having a positive refracting power;
• a lens component consisting of a lens element (L12) having a negative refracting power and a lens element (L13) having a positive refracting power cemented together;
• and
• a lens component consisting of a lens element (L14) having a negative refracting power and a lens element (L15) having a positive refracting power cemented together, and
• wherein said second lens unit comprises at least two negative lens elements and has at least one aspherical surface.

A zoom optical system comprising a lens system, said lens system consisting of, in order from an object side:

• a first lens unit having a positive refracting power;
• and
• a second lens unit having a negative refracting power,
• in variable magnification change from a wide-angle end position through a telephoto end position, each of said first lens unit and said second lens unit being moved toward the object side in such a manner that a space between said first lens unit and said second lens unit decreases,
• wherein said first lens unit comprises:
• a single-lens component arranged on a most object side and consisting of a positive lens element with an object-side surface thereof being convex toward the object side;
• and
• at least two cemented-lens components each consisting of a positive lens element and a negative lens element cemented together, and
• wherein the following condition is satisfied:
• fT/fW>2.7
• where fT is a focal length of the entire zoom optical system in the telephoto end position and fW is a focal length of the entire zoom optical system in the wide-angle end position.