| 摘要 |
<p>[Problem] To produce a zoom lens in which compactness has been maintained while increasing the magnification to 100X or more and widening the angle. [Solution] This zoom lens comprises, in order from the object side, a positive first lens group (G1) that is fixed when varying the magnification, a negative second lens group (G2) that moves from the object side to the image side when varying the magnification, a positive third lens group (G3) that moves when varying the magnification, a positive fourth lens group (G4) that moves from the image side to the object side when varying the magnification, and a positive fifth lens group (G5) that is fixed when varying the magnification. This zoom lens employs a floating method whereby the third lens group (G3) and the fourth lens group (G4) move relative to one another when varying the magnification. The imaging magnifications of a combined lens group, comprising the third and fourth lens groups, and the second lens group (G2) each pass the -1X point simultaneously when varying the magnification from wide angle to telephoto. If the focal length at the wide angle end is defined as fw, and the largest and smallest values of the distance between the third lens group (G3) and fourth lens group (G4) when varying the magnification are defined as Dg34max and Dg34min, the following conditional equation (1) is satisfied. (Dg34max-Dg34min)/fw>2.5 ... (1)</p> |
