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

Optical: systems and elements – Lens – With variable magnification

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359686, G02B 1514

Patent

active

055046266

ABSTRACT:
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, and configured so as to change a magnification thereof by varying at least one airspace reserved between the first lens unit and the second lens unit. Owing to a fact that a distance as measured between principal points of the first lens unit and the second lens unit is defined within a certain definite range, the zoom lens system has a wide field angle of 70.degree. or larger, a high vari-focal ratio of approximately 4, a telephoto ratio of approximately 1.5 at a tele position thereof and a compact size, and can be manufactured at a low cost.

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