17 Sep 火星習作
17 Sep 火星習作
這是昨晚的火星習作,極冠的曝光還是掌握不好.
附上兩種不同的processing,以作比較.我比較喜歡自然的感覺.
請各位指教.
17 Sep, 14:51 UT
stack 404 frames using Registax.
附上兩種不同的processing,以作比較.我比較喜歡自然的感覺.
請各位指教.
17 Sep, 14:51 UT
stack 404 frames using Registax.
- 附加檔案
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- Mars 17 Sep, Natural
- mars-404-09171451-b.JPG (15.38 KiB) 已瀏覽 14800 次
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- Mars 17 Sep, Detailed Processing
- mars-404-1-09171451-a.JPG (17.14 KiB) 已瀏覽 14800 次
Generally the albedo 反照率 i.e. the reflectivity of Mars is only 16%. Ice/snow (i.e. the polar cap) reflects almost 100%. The range is too large (almost 3 stops if we talk about photography, i.e. 3級曝光), larger than using negative film 負片菲林.
Webcam usually supports 24bit colour image, that means each R/G/B channel has 8-bit level of brightness, which is 256 distinct level. I do not know the exposure latitude of webcam but I do not think it is wider than negative film.
Regards
Webcam usually supports 24bit colour image, that means each R/G/B channel has 8-bit level of brightness, which is 256 distinct level. I do not know the exposure latitude of webcam but I do not think it is wider than negative film.
Regards
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