你用的膠捲感光度是多少?
What's the speed of the film you're using?
光度計用來測量光的性質、尤其是光的強度和通量的儀器
An instrument for measuring a property of light, especially luminous intensity or flux.
光度視網膜亮度單位,相當於每平方米有一燭光亮度的表面,通過一平方毫米的瞳孔區域,到達視網膜的光線數量
A unit of retinal illumination, equal to the amount of light that reaches the retina through 1 square millimeter of pupil area from a surface having a brightness of 1 candela per square meter.
北極星第二星的光度中的一顆星,位於小熊星座把柄的末端,幾乎位於北天極
A star of the second magnitude, at the end of the handle of the Little Dipper and almost at the north celestial pole.