Rectilinear distortion: All binoculars show a slight pincushion distortion, which is intentionally installed to eliminate the globe effect and in this way to provide a smooth panning.

• 直线扭曲：所有望远镜都表现出轻微的枕形畸变，这是有意如此的，为了消除球面效应，并通过此法提供一个平滑视场盘。