焦段就是指变焦镜头焦距的变化范围。镜头焦段的划分:首先是标头--就是所谓的标准镜头。它的视角在43度左右,这时照片的透视是最接近人类眼睛。片幅不同,标头的焦距也是不同的。135片幅的标准镜头在50mm左右,120的6×6标头焦距80mm,300d的标头在50÷1.5=33mm左右
镜头按焦段 focal distanc
镜头焦段线框照明系统 bright line Illuminator
分段聚焦 segment focusing
多段聚焦 multistage focusing
区分地段焦点平面偏差 site FPD
焦溜肉段 Sauteed Pork
焦作城区段 Jiaozuo City Section
焦点身段 focus figure
我一直和一个黑白印刷商有合作。你平时使用什么机器和什么焦段的镜头?。
I have a black and white printer who I have worked with for a long time.
同样的锐度下降问题也出现在镜头的长焦段(包括中央的锐度也下降得厉害)。
The same applies to the sharpness in general (including the image center) at the lens' tele setting.
柯达的系统令人印象深刻,在1/25秒的快门速度时,大多数时候在各个焦段都能拍出锐利的照片,尽管快门再慢就不行了。
Kodak's system is reasonably effective , producing sharp images most of the time at full zoom anda shutter speed of 1/25th of a second, although slower speeds defeated it.
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