| 摘要 |
PROBLEM TO BE SOLVED: To provide a photographing optical system capable of holding an excellent image-focusoing function ranging from a wide-angle end to telephoto- end with a small number of constitutive lenses, and allowing a zoom variable power around three magnifications. SOLUTION: This zoom lens includes two groups of positive and negative powers in order from the object side, and a first group G1 has negative power and positive power components, an object side face on the most object side of the first group G1 is formed into a recessed face, a joined lens is provided inside the first group G1, a positive lens is provided inside a second group G2, the first group G1 is a positive power lens group comprising a negative lens, a joined lens joining negative and positive lenses, and a diaphragm, in order from the object side, the second group G2 is a negative power lens group comprising a negative lens, a positive lens, and a negative lens, and the total number of the lenses is six pieces.
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