攝影問答--SLR 同DC 影天文相邊樣好D?
Hello Wah!
May I question why 多數DC的曝光時間短,影出來的noise較多.
As I understand that noise from DC is mainly from thermal noise. When the CCD is switched on for a considerable long time, then there are pixels getting hot and come up with "hot-pixel". Therefore the longer the exposure, the higher the noise level it should be.
BTW, how is your cooled CCD from China? Tonight is great for a test (as well as those Canon 300D owners).
Kai Ming
May I question why 多數DC的曝光時間短,影出來的noise較多.
As I understand that noise from DC is mainly from thermal noise. When the CCD is switched on for a considerable long time, then there are pixels getting hot and come up with "hot-pixel". Therefore the longer the exposure, the higher the noise level it should be.
BTW, how is your cooled CCD from China? Tonight is great for a test (as well as those Canon 300D owners).
Kai Ming
那你推介哪一台平價小型赤道儀呢Subaru 寫:以現時大家一般用的小型器材(幾千蚊級數的)來影星野及星雲星團, 還是用菲林影會比較靚.
至於月球行星, DC就已經遠遠拋離菲林了, 對技術的要求也無噤高.
我見現時DC/DSLR的問題是曝光時間不能太長, 對於暗淡的DSO很難影到足夠的s/n ratio, 而且對紅色星雲也不大敏感, 所以我覺得還未合格.
如果玩天文攝影入門, 不妨平平地買部SLR玩住先, 一部SLR加支標準鏡($3,000)加上赤道儀追蹤已經可以影到好多靚相.
呢張天鵝座就只是用一台平價小型赤道儀、一支幾百蚊嘅折射鏡做追蹤、一部幾百蚊嘅SLR及一支幾百蚊嘅二手標準鏡就已經影到.
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