The effective focal length of a lens is the distance from the primary plane of the lens to the focal point, when focusing light that is coming from infinity. The primary plane is determined mathematically and is located at a point within the lens, therefore making it extremely difficult to work with its position for mounting purposes. The back focal length is the distance from the back of the lens to the focal point of the lens when focusing light from infinity. The back focal length is much easier to use when determining a mounting position for a lens. See the accompanying diagram below:
或查看各区域电话
报价工具
只需输入商品编号
Copyright 2023, 爱特蒙特光学(深圳)有限公司。— 广东省深圳市龙华工业东路利金城科技工业园3栋5楼 518109 - 粤ICP备2021068591号