Wide-angle zoom lens system having a high vari-focal ratio

A wide-angle zoom lens system having a high vari-focal ratio comprising, in order from the object side:

• a first lens unit having a negative refractive power,
• a second lens unit having a negative refractive power, and
• a third lens unit having a positive refractive power,
• wherein size of at least one airspace reserved between said first lens unit and said second lens unit is varied to change focal length of said zoom lens system, and
• wherein said zoom lens system satisfies the following condition (1):
• (1) 0.30<H.sub.W12 /(H.sub.W12 +H.sub.W23)<1.0
• wherein the reference symbol H.sub.W12 represents a distance as measured between a rear principal point of said first lens unit and a front principal point of said second lens unit at a wide position of said zoom lens system, and the reference symbol H.sub.W23 designates a distance as measured from a rear principal point of said second lens unit to a front principal point of said third lens unit at a wide position of said zoom lens system,
• wherein said third lens unit comprises at least two subunits, and
• wherein a change of the focal length from the wide position to the tele position of said zoom lens system is performed by moving said first lens unit toward the image side and then toward the object side, and moving said at least two subunits disposed in said third lens unit so as to shorten a focal length of said third lens unit and shift a front principal point of said third lens unit toward the object side.

A wide-angle zoom lens system having a high vari-focal ratio comprising, in order from the object side:

• a first lens unit having a negative refractive power,
• a second lens unit having a negative refractive power, and
• a third lens unit having a positive refractive power,
• wherein size of at least one airspace reserved between said first lens unit and said second lens unit is varied to change focal length of said zoom lens system, and
• wherein said zoom lens system satisfies the following condition (1):
• (1) 0.30<H.sub.W12 /(H.sub.W12 +H.sub.W23)<1.0
• wherein the reference symbol H.sub.W12 represents a distance as measured between a rear principal point of said first lens unit and a front principal point of said second lens unit at a wide position of said zoom lens system, and the reference symbol H.sub.W23 designates a distance as measured from a rear principal point of said second lens unit to a front principal point of said third lens unit at a wide position of said zoom lens system,
• wherein said first lens unit comprises a negative lens component and a positive lens component,
• wherein said second lens unit comprises a first subunit having a positive refractive power and a second subunit having a positive refractive power, and
• wherein zooming of said zoom lens system from the wide position to the tele position thereof is performed by moving said first lens unit toward the image side and then toward the object side so as to narrow an airspace reserved between said first lens unit and said second lens unit, and moving said third lens unit so as to narrow an airspace reserved between said second lens unit and said third lens unit.