| 摘要 |
A variable-power imaging optical system and an image pickup device using the same are provided to reduce a lens movement quantity and more shorten the entire lens length. The first lens group(G1) having a negative refractive index, the second lens group(G2) having a positive refractive index, and the third lens group(G3) for aberration correction are arranged in regular order from an object side. The first lens group(G1) has the first lens(L1) formed as a negative lens and the second lens(L2) formed as a positive lens in regular order from the object side. The second lens group(G2) has the third lens(L3) formed as the positive lens, the fourth lens(L4) formed as the negative lens, and the fifth lens(L5) for aberration correction having an aspheric surface in regular order from the object side. The third lens group(G3) has the sixth lens(L6) for aberration correction. The first lens(L1) is formed as a glass lens. The second lens(L2) is formed as a plastic lens which is formed as an aspheric surface at the object side. The third lens(L3) is formed as a double convex glass lens whose both surfaces are a spheric surface. The fifth lens(L5) is formed as a plastic lens of a meniscus shape whose one surface or more are formed as an aspheric surface. The sixth lens(L6) is formed as a positive lens. The first lens group(G1) and the second lens group(G2) are mutually and independently moved on an optical axis to perform zooming.
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