The deviation of focus,magnification and parallelism of optical axis duc to changign the magnification in binocular with zoom type of triplex eyepiece are introduced.

• 本文介绍采用三组元变焦目镜的双筒望远镜在变倍过程中产生的离焦、倍率差、光轴平行差，较详细地导出这些误差的表达式，同时结合具体实例计算出误差的影响关系。