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一般照相机的物距调节环(或调节钮)的最近距离都是一个确定值(例如1m、0 8m或0 45m等)。在无近摄接圈时 ,为把较小物体摄得较大 ,距离需小于上述确定值 ,为此可加“近摄镜片”或取一远视眼镜片放置在照相机镜头前。本文推导装置镜片前后新旧物距和新旧放大率等的关系公式 ,并列出多幅实用数表 ,扩大了近摄镜的用途。目前不少照相机已不具备物距刻度而用“摄距”刻度代替 ,本文呼吁尽快恢复。
The most recent distance between the object distance adjustment ring (or control knob) of a typical camera is a certain value (for example, 1m, 0 8m or 0 45m, etc.). In the case of no close loop, in order to capture smaller objects larger, the distance required to be less than the above-mentioned value, for which you can add “close-up lens” or take a farsighted glasses placed in front of the camera lens. This article deduces the relationship between new and old object distance and new and old magnification before and after the device lens, and lists a number of practical digital form, expanding the use of close-up lens. At present, many cameras do not have the object distance scale instead of the “distance” scale instead, this article calls for the restoration as soon as possible.