Re: [問題] 感光元件尺寸單位 1" = 16mm ?!
※ 引述《justdemon (人生的轉捩點)》之銘言：
: 最近深刻體會到感光元件大小的重要性
: 所以開始尋找大片幅的DC
: 看啊看著 卻覺得怎麼算都不太對勁
: 為什麼怎麼算對角線的長度都不如標示長度呢?!
: 最後才驚為天人的發現 原來1" = 16mm ?!
: 可是怎麼Google卻都找不到原因
: 只看到一些跟CRT 圓取方之類的東西
: 就是沒有告訴我為什麼1"=16mm啊....
: 不知道這邊是否有前輩曾經研究過可以給小弟解答呢?
: 感謝~
Dpreview上解釋名詞有大概說一下
http://www.dpreview.com/learn/?/Glossary/Camera_System/sensor_sizes_01.htm
Sensors are often referred to with a "type" designation using imperial
fractions such as 1/1.8" or 2/3" which are larger than the actual sensor
diameters. The type designation harks back to a set of standard sizes given
to TV camera tubes in the 50's. These sizes were typically 1/2", 2/3" etc.
The size designation does not define the diagonal of the sensor area but
rather the outer diameter of the long glass envelope of the tube. Engineers
soon discovered that for various reasons the usable area of this imaging
plane was approximately two thirds of the designated size. This designation
has clearly stuck (although it should have been thrown out long ago). There
appears to be no specific mathematical relationship between the diameter of
the imaging circle and the sensor size, although it is always roughly two
thirds.
反正看來是從電視陰極射線管之類的東西沿用過來的尺寸，
其實尺寸指的是射線管子外的玻璃套大小....
標示尺寸會比實際大，大概就是2/3~
英文不好，其他自己看吧XD
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