Patent ID: 6710935
Filing Date: 2004-03-23
Classification: G02B

Abstract:
A zoom optical system comprising, in order from an object side:a first lens unit having positive refractive power; a second lens unit having positive refractive power; and a third lens unit having negative refractive power, wherein a magnification is changed from a wide-angle position to a telephoto position by moving the lens units toward the object side so as to widen an airspace between said first lens unit and said second lens unit and narrow an airspace between said second lens unit and said third lens unit, and wherein said zoom optical system satisfies the following conditions: 0.5T/fT<0.8 0.5G1/fW<1.45 0.8G2/fW<1.2 0.4G3/fW|<0.5 where a reference symbol fW represents a focal length of the zoom optical system at the wide-angle position, a reference symbol fT represents a focal length of the zoom optical system at the telephoto position, a reference symbol LT represents a distance as measured from a most object side surface to an image surface on an optical axis at the telephoto position, a reference symbol fG1 represents a focal length of the first lens unit, a reference symbol fG2 represents a focal length of the second lens unit, and a reference symbol fG3 represents a focal length of the third lens unit.