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In-camera noise reduction and shooting RAW
jhefti
Registered Users Posts: 734 Major grins
OK, so I've just had a minor revelation thanks to Matt Saville about camera settings and how they carry over to PP--they don't aside from the initial thumbnail rendering.
That got me thinking about the in-camera noise reduction setting, which gives the option to disable it. My question is whether or not I should disable it if I am shooting RAW and de-noising in PP. Or does it make a difference? (I shoot with Canon bodies.)
That got me thinking about the in-camera noise reduction setting, which gives the option to disable it. My question is whether or not I should disable it if I am shooting RAW and de-noising in PP. Or does it make a difference? (I shoot with Canon bodies.)
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No, it makes no difference in the raw data that is captured. It might travel as metadata that some raw converters could read as they read other camera settings -- WB, sharpening, saturation, etc.
RadiantPics
That's what I thought. My only pause for concern is that I know camera manufacturers claim that a more powerful processor (e.g. the dual Digic V processors that the 1Dx is going to have) helps reduce noise, suggesting that the camera has some role in noise reduction. It never made much sense to me--at least for RAW images--to have the camera reduce noise, as this is much more easily and effectively taken care of in PP. Perhaps these claims are directed to JPEG shooters, who often do use noise reduction in camera.
If the benefit of reduced noise comes from "a more powerful processor," you'll get that benefit regardless of whether you shoot jpeg or raw.
The camera surely can play a role in noise reduction. Some Nikons, for instance, fare worse than Canons for noise at high ISO settings.
RadiantPics
I guess my main question is whether or not enabling/disabling high ISO noise reduction on the camera has any effect on this process.
And as far as in-camera noise reduction goes, it seems to me that us RAW shooters can at best break even with this, and likely lose, as this is a form of post-processing even though it is done in the camera. It could just as easily be done on a computer during the PP, and certainly with more flexibility. Most computers have faster processors--albeit not dedicated to these specific algorithms--and in any case speed is not really the issue, clean images are.
Only if your raw converter can read that particular metadata. Otherwise, no. Camera settings don't affect what raw data gets captured by the sensor.
RadiantPics
I thought it was established that Active D-Lighting in Nikon settings could affect raw data? At least I've read that in numerous places.
Tom
RAW means raw , unchanged , in any way
what the sensor saw is what you get
/ɯoɔ˙ƃnɯƃnɯs˙ʇlɟsɐq//:dʇʇɥ
It isn't clear to me exactly how Active D works, and Nikon's own explanation leaves it unclear (to me). Consider this diagram from Nikon:
Are the three steps in the box (exposure, processing active d-lighting) all part of the raw data? I don't know. Nikon says: "Unlike conventional D-Lighting, which makes adjustments after the image is converted to JPEG, Active D-Lighting allows exposure and image processing optimization prior to JPEG conversion,..." (emphasis added).
Does this "prior to jpeg conversion" mean that the raw data is affected by Active D? Again, I don't know.
I don't shoot Nikon, but if I did, I would turn Active D off.
RadiantPics
As far as noise reduction in raw images that has been some discussion of this over on dpreview
http://forums.dpreview.com/forums/read.asp?forum=1039&message=33718870
that claims that Nikon does apply some noise reduction even to the raw image.
Also some cameras let you make an image of a long duration dark frame and apply that to low light pictures that are taken. I think that this is applied to the raw image as a kind of noise reduction.
http://www.danalphotos.com
http://www.pluralsight.com
http://twitter.com/d114
Nikon apply NR when off (to the JPG) , IF the ISO is higher then Hi 0.3
how often you use that setting ?
no , nothing is done to the RAW
as @ Peano said : NEF and CR2 files contain additional data about the shot , but the RAW-image itself remains pure
/ɯoɔ˙ƃnɯƃnɯs˙ʇlɟsɐq//:dʇʇɥ
That used to be the case, but, starting with the Nikon D300 and D3 and the Canon 5D MKII, that no longer appears to be true. There is a growing body of evidence which suggests that both Nikon and Canon are using "some" image processor noise reduction (NR) "prior" to saving the RAW files. Further, the user has no opportunity to moderate this affectation.
Still, it is correct to say that the RAW files are the closest the user can get to the digital data readout from the imager chip.
For more information about the Nikon NR and black clipping (the link is to Nikon D300 research, but applies to modern Nikon dSLRs in general):
http://theory.uchicago.edu/~ejm/pix/20d/posts/tests/D300_40D_tests/
Like I said before, Canon started doing something similar starting with the 5D MKII. Pentax and Sony are also employing something similar to improve SNR and DR figures. Nikon was simply the first to adopt the technology.
Moderator of the Cameras and Accessories forums
NR can occur in many ways. The one we are most familiar with is looking at the whole image, then doing some sort of averaging procedure and statistical guessing to reduce noise. However, in the general field of noise reduction there are also hardware-based approaches, which need to be done at the time the signal is generated and/or captured. I'm not sure what these might be specifically for cameras, but basically they all use some sort of real time information that the hardware provides to increase the signal-to-noise ratio (SNR); information that is usually not stored (and many times cannot be stored) in a data file. Perhaps that is what's going on here...