| 摘要 |
PROBLEM TO BE SOLVED: To provide a compact zoom lens having a half field angle of 45 degrees or more at a short focal end, an F number of 2.0 or less at the short focal end, an F number of approximately 3.0 at a long focal end, a small number of lenses and a resolution corresponding to an imaging element of 10 to 20 million pixels.SOLUTION: The zoom lens comprises a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, a third lens group G3 having positive refractive power and a fourth lens group G4 having positive refractive power, which are disposed in order from an object side. In the zoom lens, when varying magnification from a short focal end to a long focal end, an interval between the first lens group G1 and the second lens group G2 is increased, an interval between the second lens group G2 and the third lens group G3 is decreased, and an interval between the third lens group G3 and the force lens group G4 is changed. The first lens group G1 is composed of one positive lens, and the third lens group G3 is composed of a positive lens, a positive lens, a negative lens, and a positive lens. The interval between the first lens group G1 and the second lens group G2 and the interval between the second lens group G2 and the third lens group G3 are prescribed so as to satisfy a predetermined conditional expression. Accordingly, a decrease in F number at the long focal end and high performance are achieved. |
