Taking lens device

A digital camera comprising:

• an optical lens device, and
• a memory;
• wherein said optical lens device comprises a zoom lens system, having an optical system which comprises a plurality of lens units and which achieves zooming by varying unit-to-unit distances;
• and an image sensor for converting an optical image formed by the zoom lens system into an electrical signal;
• wherein the zoom lens system comprises at least, from an object side thereof to an image side thereof, a first lens unit having a positive optical power, a second lens unit having a negative optical power, a third lens unit having a positive optical power, and a fourth lens unit having a negative optical power, and the following conditional formula is fulfilled:
• 1.1<f1/fT<2.5
• where
• f1 represents a focal length of the first lens unit;
• and
• fT represents a focal length of an entirety of said optical system at a telephoto end;
• and
• wherein said memory is adapted for storing image data from said image sensor, and said memory is not removable from said digital camera.

An optical device comprising:

• a zoom lens system which comprises a plurality of lens units and which achieves zooming by varying unit-to-unit distances;
• and
• an image sensor for converting an optical image formed by the zoom lens system into an electrical signal,
• wherein the zoom lens system comprises at least, from an object side thereof to an image side thereof, a first lens unit having a positive optical power, a second lens unit having a negative optical power, a third lens unit having a positive optical power, and a fourth lens unit having a negative optical power, the first lens unit being moved as zooming is performed, and
• wherein the following conditional formula is fulfilled:
• 0.3<D34W/D34T<2.5
• where
• D34W represents an aerial distance between the third lens unit and the fourth lens unit at a wide-angle end;
• and
• D34T represents an aerial distance between the third lens unit and the fourth lens unit at a telephoto end.

A digital camera comprising:

• an optical lens device, and
• a memory;
• wherein said optical lens device comprises a zoom lens system which comprises a plurality of lens units and which achieves zooming by varying unit-to-unit distances;
• and an image sensor for converting an optical image formed by the zoom lens system into an electrical signal;
• wherein the zoom lens system comprises at least, from an object side thereof to an image side thereof, a first lens unit having a positive optical power, a second lens unit having a negative optical power, a third lens unit having a positive optical power, and a fourth lens unit having a negative optical power, the first lens unit being moved as zooming is performed, and wherein the following conditional formula is fulfilled:
• 0.3<D34W/D34T<2.5
• where
• D34W represents an aerial distance between the third lens unit and the fourth lens unit at a wide-angle end;
• and
• D34T represents an aerial distance between the third lens unit and the fourth lens unit at a telephoto end;
• and
• wherein said memory is adapted for storing image data from said image sensor, and said memory is not removable from said digital camera.