| 摘要 |
PURPOSE:To obtain a high-performance zoom lens by arranging a plastic lens which has one aspherical surface with extremely low refracting power nearby at least either of the 4th and the 5th lens components among five lens components. CONSTITUTION:The zoom lens consists of the five lens components; the 1st lens component has three-element constitution and positive refracting power, the 2nd lens component has three-element constitution and negative refracting power, and the 3rd and the 4th lens components both have one-group, one- element constitution and negative and positive refracting power respectively. The plastic lens which has almost no refracting power is arranged nearby either of the 4th and the 5th lens component and at least one surface of the plastic lens is made aspherical. This plastic aspherical surface lens compensates a spherical aberration and the refracting power of the plastic lens is reduced to suppress aberration variation due to temperature variation and humidity variation. Consequently, aberrations are compensated excellently with good balance to obtain the zoom lens of a X6 large power variation ratio and an about F number 1. |
