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40D noise reduction question

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  • Aug 30th, 2008 12:07 pm
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Deal Addict
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Nov 10, 2003
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40D noise reduction question

I'm looking at getting a 40D one of these days (maybe a 50D when it comes out) but there's still one thing I'm not sure about.
The 40D has a custom function for noise reduction. With this custom function turned on, does the RAW file get affected by the nose reduction algorithm? Or just the jpegs (if set to only output jpegs)?
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Deal Guru
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Toronto
The RAW should not be affected. There is no NR applied to Canon's RAWs.
Deal with it.
Deal Guru
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Pickering
If you shoot RAW (I have never shot a JPEG with my 40D) and you turn on the noise reduction, you will see it in the picture.
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AudiDude wrote: If you shoot RAW (I have never shot a JPEG with my 40D) and you turn on the noise reduction, you will see it in the picture.
Applied to the RAW?
Deal with it.
Deal Guru
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Pickering
It'll reduce the chroma noise.
Deal Guru
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Markham/Mississauga
Just confirmed on my own 40D, shot at F2.8, ISO 3200, fluorescent WB in RAW.

Noise reduction not applied - only chroma noise. You will also notice that with NR off in high ISO settings, the buffer goes up to 14 shots. With it on, buffer is 6 shots.

In JPEG, its more prevailent. With it on, buffer allows 6 shots. With it off, buffer is 75 shots.
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CSAgent wrote: Just confirmed on my own 40D, shot at F2.8, ISO 3200, fluorescent WB in RAW.

Noise reduction not applied - only chroma noise. You will also notice that with NR off in high ISO settings, the buffer goes up to 14 shots. With it on, buffer is 6 shots.

In JPEG, its more prevailent. With it on, buffer allows 6 shots. With it off, buffer is 75 shots.
So it's still not clear to me. RAW file IS or IS NOT modified by noise reduction being turned on?
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Outsider wrote: So it's still not clear to me. RAW file IS or IS NOT modified by noise reduction being turned on?
There are two types of noise reduction in the camera. High ISO and Long Exposure. High ISO NR will reduce the chroma noise, so the picture will have a less red splotchy look and I can see it immediately after turning it on.

Long exposure noise reduction makes the camera shoot two images. One is the actual picture, and the other is with the shutter closed. The picture with the shutter closed will show any hot pixels. This data is compared to the actual picture and the hot pixels are eliminated by adding data from pixels around the hot ones to eliminate the red dots you will see from hot pixels.

This is why long exposure NR will reduce the amount of frames you can take, because the camera is taking two shots for every one you think you are taking and it has to process the information and apply it.

So the picture, technically, is modified in RAW at your request by activating those features.

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