Canon 400D d noise ...

[elton]

Canon 400D d noise 多到好厲害!!!

[Wah!!]

豆貓有300d, 我有350d.
搵一次同場比較下至得.

[Chanlunlun]

Dear Mr. Elton,

I had made this comparsion long ago :- EOS 10D has noise pixels 10 times less than EOS300D, at thesame ISO setting and same exposure time ( 5 minutes at ISO800). I believe that EOS30D should similarly outperform the EOS400D by the same extend.

Best regards
Chan Yuk Lun

[Wah!!]

Were you using RAW mode at the same temperature with noise reduction disabled?

This is a good reference website to show how the temperature affects thermal noise (hotpixels):
http://www.centralds.net/en/test-2.htm

[Patshek]

我部d40長曝下, 會有紅色一達野o係左上角
聽人講呢d叫 amp noise

但係睇400d 又好似無wor......>.<

有無得避免呢隻noise ga？

[豆豸苗]

搵返個舊 post 俾大家參考下:
http://www.hkastroforum.net/viewtopic.p ... c&start=15

[豆豸苗]

豆貓有300d, 我有350d.
搵一次同場比較下至得.

同唔同場我諗都唔係咁重要, 最主要都係要呢幾樣野一樣:

- 溫度
- iso
- 曝光時間

熄 noise reduction function, 開機即刻影一張 5 分鐘~
夏天溫度高左. 等我得閒用部 300D 試返幾張 25C 0既 darkframe 先.

[XR250]

我部d40長曝下, 會有紅色一達野o係左上角
聽人講呢d叫 amp noise

但係睇400d 又好似無wor......>.<

有無得避免呢隻noise ga？

Nikon的DSLR 9成9都有amp glow問題。其實Canon機都有，不過無nikon咁嚴重。

如果用nikon DSLR要解決這個問題，最簡單的方法就係開了機內的noise reduction。當長時間曝光後，DSLR會自動影多一張Dark frame去處理這些amp glow及hot pixel。

正路做法係唔開noise reduction，當拍攝完成後，馬上在相同溫度下多拍幾張dark frame，然後放上用電腦再處理這些amp glow及hot pixel。
以上方法適合所有DSLR及CCD，網上有好多詳細的資料，我都唔多講啦。

[Wah!!]

豆貓有300d, 我有350d.
搵一次同場比較下至得.

同唔同場我諗都唔係咁重要, 最主要都係要呢幾樣野一樣:

- 溫度
- iso
- 曝光時間

熄 noise reduction function, 開機即刻影一張 5 分鐘~
夏天溫度高左. 等我得閒用部 300D 試返幾張 25C 0既 darkframe 先.

一齊試就可以滿足晒d條件啦
人多湊熱鬧嘛~~~

[豆豸苗]

一齊試就可以滿足晒d條件啦
人多湊熱鬧嘛~~~

咁我突然好想知0係農莊 3x 度高溫下測試 5 秒 darkframe 會出左0的乜野出來...........

[elton]

Thanks for everyone's comment.

However, in Wah's website linked, the 5D noise are even more than 350D.

Seems through the comparison, smaller pixel size is the main contributor of noise generation, regardless of the 'better' noise control circuit in later models.

Perhaps, I could have made a wrong decision for selling 300D and buying the 400D on one single day.

Dear Mr. Elton,

I had made this comparsion long ago :- EOS 10D has noise pixels 10 times less than EOS300D, at thesame ISO setting and same exposure time ( 5 minutes at ISO800). I believe that EOS30D should similarly outperform the EOS400D by the same extend.

Best regards
Chan Yuk Lun

[Wah!!]

在相同的溫度下, 相對於 300D, 400D 的 CMOS 有較小的像素, 較多的 hotpixel.
因為不是每一顆像素都是hotpixel, 而是更多比例的像素成為了 hotpixel, 所以對於兩者是否因果關係, 我就有所保留.
我覺得有可能是 CMOS 製作過程的問題.

P.S. hotpixel 是一些有缺憾的像素, 位置固定. 與隨機出現的噪點 (white noise/random noise)不同.

[elton]

Agree and disagree.

300D is 6Mega pixels, and 400D is 10Mega pixels. Let's say if 300D got 6 hot pixels, then 400D should have 10 hot pixels.
However, from the 100% crop photos, 400D hot pixels density is much higher... It seems not according to ratio...

Totally agree that smaller pixel size will be easier to have manufacturering problem (we are talking about microns... ) and turn to hot pixels easier, and at the same time, the random noise will also be higher due to smaller area, less photons ma.

在相同的溫度下, 相對於 300D, 400D 的 CMOS 有較小的像素, 較多的 hotpixel.
因為不是每一顆像素都是hotpixel, 而是更多比例的像素成為了 hotpixel, 所以對於兩者是否因果關係, 我就有所保留.
我覺得有可能是 CMOS 製作過程的問題.

P.S. hotpixel 是一些有缺憾的像素, 位置固定. 與隨機出現的噪點 (white noise/random noise)不同.

[Wah!!]

I think the "noise" you mean is hotpixels, because the noise of above darkframes all mostly hotpixels rather than random noise.

There is one very important method to differ them:
Stacking doesn't help to reduce hotpixels, but can help to reduce random noise.

[Wah!!]

400D hot pixels density is much higher...

This is exactly the same as that I said "更多比例的像素成為了 hotpixel"