# How much NR and Color Noise Reduction in Camera and Lightroom



## alaios (Jan 29, 2016)

Dear all,
how much Noise Reduction and Color noise do you leave your camera to do ? I have tried turning both options off but then the problem is that lightroom sliders tend to be applying universally noise and color noise reduction.
When are the times you think can do effectively? What about for example leaving the options in camera to LOW instead of OFF?

I would like to thank you for your reply
Regards
Alex


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## Hal P Anderson (Jan 29, 2016)

I shoot raw, and it doesn't matter what I set noise reduction in the camera to. Lightoom ignores it. All noise reduction has to happen in post.


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## Johan Elzenga (Jan 29, 2016)

Hal P Anderson said:


> I shoot raw, and it doesn't matter what I set noise reduction in the camera to. Lightoom ignores it. All noise reduction has to happen in post.



That is true for high ISO noise reduction, but it is not true for long exposure noise reduction ('dark frame subtraction'). Long exposure (more than 1 second shutter speeds) is also applied to raw images, so you should definitely turn this on in the camera!


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## tspear (Jan 30, 2016)

JohanElzenga said:


> That is true for high ISO noise reduction, but it is not true for long exposure noise reduction ('dark frame subtraction'). Long exposure (more than 1 second shutter speeds) is also applied to raw images, so you should definitely turn this on in the camera!



Johan,

Can you expand/explain some more? I am getting into some long exposure images (5-30 seconds), but I always have my ISO at 100 for these shots.

Tim


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## Replytoken (Jan 30, 2016)

tspear said:


> Johan,
> 
> Can you expand/explain some more? I am getting into some long exposure images (5-30 seconds), but I always have my ISO at 100 for these shots.
> 
> Tim



Dark Frame subtraction, which is usually listed in the menu under a variety of names depending on camera manufacturer, should be independent of your ISO setting, and is generally recommended for long exposures.  It can take a bit of processing power (and time) so you will need to account for that when shooting.  There may be cases where it is not recommended, but I have not heard any over the years (unlike general noise reduction).

--Ken


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## Johan Elzenga (Jan 30, 2016)

tspear said:


> Johan,
> 
> Can you expand/explain some more? I am getting into some long exposure images (5-30 seconds), but I always have my ISO at 100 for these shots.



Dark frame subtraction is irrespective of your ISO setting. If you shoot with a long shutter speed (one second or longer), your image will show a special kind of noise called 'fixed pattern noise'. It is called this way because the noise pattern is always the same: it is created by small differences between the individual sensor pixels, because the sensor heats up. Dark frame subtraction is a clever technique to reduce this kind of noise. After the normal exposure, the camera will take another exposure for the same length of time, but with a closed shutter. That second exposue will create a black image, with the same fixed pattern noise. By subtracting that second image from the real exposure, the pixed pattern noise is removed. Because you do this with the original data, you can also do it with a raw image. It is not like post-processing high ISO noise.

You should always use this kind of noise reduction for night photography, unless you are shooting 'star trails'. The disadvantage of this technique is that your camera will use double the exposure time between shots, so you would get 'gaps' in your star trails if you used this. For individual night shots however, it is a very effective technique. In your camera it is simply called 'long shutter speed noise reduction'. Most cameras have an 'automatic' setting, where it is applied to every shot with an exposure of one second or more.


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## Hal P Anderson (Jan 30, 2016)

Tim,

https://en.wikipedia.org/wiki/Dark-frame_subtraction

Long-exposure noise reduction doubles the amount of time it takes to make a shot. If you have a 3-second exposure, your camera will take that with the shutter open, and then take another 3-second exposure with the shutter closed. Then it subtracts the second exposure from the first and stores the resultant image on the card. Indeed, this is done for raw files as well as JPEGs.


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## alaios (Jan 30, 2016)

Hal P Anderson said:


> I shoot raw, and it doesn't matter what I set noise reduction in the camera to. Lightoom ignores it. All noise reduction has to happen in post.


are you sure about this?


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## Johan Elzenga (Jan 30, 2016)

Come on, guys. Don't you read the other posts before you react?


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## themoose (Jan 30, 2016)

For my Nikon D600 I found the setting info under "Long Exposure Noise Reduction". I turned it ON to automatically create the second exposure (in camera only) for any exposures longer than 1 second. The camera only creates one final image after using the "dark frame subtraction" process. I wish I had known about this feature before my trip to Iceland photographing the northern lights but that's what I like about photography- always learning new techniques and this forum has proven a valuable resource.


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## Hal P Anderson (Jan 30, 2016)

Alex,

The controls in your camera that specify the *amount *of noise reduction only affect JPEGs. As Johan pointed out, the option to apply Long Exposure Noise Reduction applies to raw files as well. Yes, I'm sure of this.

If you use the manufacturer's software to do your raw conversions, then yes, it will take all camera settings into account, but we're talking about what Lightroom does.


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## alaios (Jan 30, 2016)

Thanks guys... I have the feeling that I read somewhere that many companies apply NR also to raws and they do that "secretly" of course

I will try tomorrow to google this


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## Johan Elzenga (Jan 30, 2016)

If if they do, what does it matter? You can't change anything about that.


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## tspear (Jan 31, 2016)

Ok, that is cool.
I am gonna have to play with that. Kinda wish I knew that before I went to France recently, we took a fair number of multi-second exposure shots at night and in the evening. I guess this means my fiance will be happy that we have to go back and do it again (she is French, so no way can I avoid it).

Tim


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