| 摘要 |
PROBLEM TO BE SOLVED: To obtain a zoom lens and a projecting device using the same capable of projecting picture information displayed on a liquid crystal display element onto a screen surface while maintaining high optical performance. SOLUTION: This zoom lens is provided with a 1st lens group having negative refractive power and fixed in the midst of zooming, a 2nd lens group having positive refractive power and moved in the midst of zooming, a 3rd lens group having negative refractive power, a 4th lens group having positive refractive power and moved in the midst of zooming, and a 5th lens group having positive refractive power and fixed in the midst of zooming in order from a 1st conjugate point side when a conjugate point having a longer distance is set as the 1st conjugate point. In the case of transiting from a zoom position at a wide-angle end to a zoom position at a telephoto end, the 2nd and the 4th lens groups are moved to the 1st conjugate point side. In the 3rd group having two or more lenses, a positive lens and a negative lens are arranged in this order from the 1st conjugate point.
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