Patent ID: 7557839

Claim:
An electronic imaging device, comprising: a zoom lens that includes a plurality of lens groups, and is configured to change a magnification by changing a distance between the lens groups; and an imaging element configured to convert an optical image formed by the zoom lens into an electric signal, wherein the zoom lens includes a first lens group having a negative focal length and a second lens group having a positive focal length sequentially from an object side, and a diaphragm on the object side of the second lens group, the diaphragm includes at least a first diaphragm having an aperture size A and a second diaphragm having an aperture size B, where 0.25<(B/A)<0.75, an aperture area of the diaphragm is controlled according to a focal length of the zoom lens, the diaphragm is configured to be controlled such that the first diaphragm is effective when the zoom lens is on a long focus end, and the second diaphragm is effective when the zoom lens is on a short focus end, a first focal length region for the long focus end and a second focal length region for the short focus end are provided, and 0.75<( f C /( f W ·f T ) 1/2 )<1.25, where f T is the first focal length, f W is the second focal length, and f C is a focal length serving as a switching point between the first focal length region in which the first diaphragm is effective and the second focal length region in which the second diaphragm is effective.