ZOOM LENS

Japanese Patent JP3387687

B2

PURPOSE: To obtain a zoom lens which has four lens groups as a whole, whose moving condition associated with the refractive power and the variable power of the respective lens groups is appropriately set and which has high optical performance over a front variable power range.
CONSTITUTION: This zoom lens has four lens groups, that is, the 1st group L1 having positive refractive power, the 2nd group L2 having negative refractive power, the 3rd group L3 having the positive refractive power, and the 4th group L4 having the positive refractive power in order from an object side. In the case of varying the power from a wide-angle end to a telephoto end, the respective lens groups are moved so that a distance between the 1st group L1 and the 2nd group L2 may be increased, a distance between the 2nd group L2 and the 3rd group L3 may be decreased, and a distance between the 3rd group L3 and the 4th group L4 may be decreased; then the focal distance (fi) of the 1st group and the focal distance (fw) of the entire system at the wide-angle end are appropriately set.

Kazuhiko Momoki

JP8196495A

March 17, 2003

March 13, 1995

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Canon Inc

G02B13/18; G02B15/20; (IPC1-7): G02B15/20; G02B13/18

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Yukio Takanashi

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