Tuesday, July 12, 2011

Do Camera Settings Affect RAW (NEF) Files?

This article is an excerpt from my upcoming book, Mastering the Nikon D7000, due out in spring 2011.

Interestingly, a RAW file is not yet an image. It is only "raw" black-and-white information from the camera's sensor, separate color information, and markers for how the camera settings were configured when you took the picture.

When you display a RAW image on your computer in a program like Nikon Capture or View NX2, you are seeing the image displayed with the settings you used at the time you took the picture. However, since a RAW file is not yet an image, none of the settings are permanently applied until you save it as a JPEG or another format.

Proof of this is how easily you can modify the RAW file with a change of settings in the computer software you are using. If you shot it with Cloudy White Balance, you can change it to Shady White Balance and it will be exactly the same as if you shot it originally in Shady instead of Cloudy. If you used the Neutral Picture Control and decide you'd rather use the Vivid Picture Control, change it in the Nikon software and it will be as if you had shot with Vivid in the first place—after you save the image as a different format. You can even save the RAW file with your new settings, but they are still not applied permanently to the image, they are just saved as new markers for later display in-computer.

Since a RAW file does not become an image until it is saved as another format, you can play with it, modify it, or change it as much as you like, and the final result will be as if you used the new settings when you first took the picture.

RAW shooters have learned that RAW (NEF) files are completely flexible and changeable after the fact. Do not worry about what settings you have used on a RAW file, you can change it later. The important thing with RAW files is that you get a correct exposure. That's one thing that cannot be changed after the fact without damaging the appearance of the image. Learn to use your histogram to validate the exposure. Make sure you have correct settings for depth of field (aperture) and motion control (shutter speed), then shoot with abandon as to settings. You can change it all later and it will be as if you used the new settings when you took the picture originally.

No RAW file exists as an image until you save it as a JPEG, TIFF, or other format. Things like noise reduction, white balance, Picture Controls, sharpening, and contrast are applied permanently only at the time the RAW file is saved as something besides a RAW file. RAW files stay raw; that's why RAW (NEF) makes such good storage format and so many experienced photographers shoot with it.

Keep on capturing time...
Darrell Young


  1. FYI, one exception to this rule is Long Exposure Noise Reduction. The reason is that, using this method, two exposures are combined in a black frame subtraction, and I've not found a way to remove the second exposures results.

    This goes to good exposure methods, one of which is Long Exposure Noise Reduction. It only applies to exposures over 8 seconds long, and you must have Long exp. NR turned on, so most of us will not use it often. I leave it turned on all the time but I rarely take exposures longer than 8 seconds.

    For those that wonder about Long Exposure Noise Reduction (Shooting Menu > Long exp. NR), it does not blur the image, after the fact, like normal noise reduction. Instead, it is concerned with pixels that get warm and bright during a long exposure. It takes the first exposure as normal, then it closes the shutter and takes a second exposure of the exact same length (except that the new D7000 claims it can make the entire combined exposure at between 1.5 and 2 times a single exposure's length). After both exposures are complete the camera examines the first and second images (in a sense) and combines them. How? Most of the second exposure is totally black, of course, since the shutter is closed. The camera sees where there are any loud, bright pixels in the second exposure and subtracts them from the first exposure.

    So, the first exposure really only gets reconfigured by the second exposures results. This does not damage the image nearly as much as regular noise reduction. However, this method of noise correction is applied to the RAW image in a permanent way. That's because it is part of the exposure itself, and becomes part of the RAW data being passed to the camera card. There is no way, that I know of, to remove the results.

  2. Advanced D-Lighting must also be used during capture, as it cannot be added after the fact (It's not the same as "D-Lighting). It's great to be able to see how well it works, and then remove it if it doesn't suit the shot....or just change it from Auto to Low, etc.

  3. If the in camera sharpening setting remains at the default in the D7000 and is not reset to zero, the in camera sharpening will be applied to an NEF file when that picture is imported into Lightroom - it can be removed in the Nikon software, but not Lightroom - with the result that there is a lot of noise created when additional sharpening is applied during picture development. I have experiencd this and it is noted on page 180 of the Magic Lantern guide to the D7000.

  4. Basically, I am spoiled by using Nikon Capture NX 2. It gives me the ability to change almost anything after the fact with a RAW file. If Lightroom indeed forces you to use a certain setting unnecessarily, I would seriously consider *not* using Lightroom. The user interface on Nikon Capture has never been very easy to use. However, the results from Nikon Capture are superior.

  5. I wonder if a comprehensive table can be found, quoting every Nikon DSLR (I own a D 700), and informing about exactly what settings will be included permanently in the Raw NEF file.

  6. Funnily enough i was searching through your book on the D90 on this topic but, not having found a definitie explanation there, did a Web search and came on your site.
    So, only changes in exposure are permanentlty stored in a Nef file (i.e. immutable). How does exposure compensation feature? Permanent or restorable in NEF files using NX?
    The reason for the question is that I find the D90 over-exposes in certain circumstances and using exposure compensation is an easier route than going full manual.

  7. If you use exposure compensation you are affecting the overall exposure so that does affect the RAW file. However, not as badly as a JPEG. The RAW file has more "headroom" for exposure adjustment after the fact so you have more room for experimentation. Use your histogram to judge exposure. It is based on an in-camera JPEG so if you get it right you'll have room to adjust exposure after the fact without introducing too much noise in the image (from brightening underexposure).

    For those who used to shoot film, I like to compare a RAW file to how a negative stores light range, while a JPEG is more like how a transparency stores light range. A film negative and RAW digital file can hold more light, in a sense (somewhat greater dynamic range or headroom). A film transparency and a JPEG are unforgiving of exposure errors.

  8. I've recently 'returned' to Nikon and initially dismissed 'Picture Control' as settings for jpeg images, leaving the NEF file untouched. One thing puzzles me though, on going through the explanation pages for Picture Control, http://imaging.nikon.com/lineup/microsite/picturecontrol/ all of the example images for different styles are in RAW(NEF) format. This seems to suggest that Picture Control does affect the RAW file, or maybe what Nikon are saying (or not saying) is if you open a NEF file in a Nikon application it will have these setting automatically applied? I'm only looking into this as I use Capture One to process NEF files so need to do some experimentation!

  9. It really does NOT matter which Picture Control you are using when shooting a RAW image. You can easily change Picture Controls after the fact in Nikon Capture NX2. However, since the computer will display the RAW file on your computer with the color markers temporarily applied, it is simple to just save the file as a JPEG with the Picture Control marked for the image.

    A Picture Control is not applied permanently to an image until you save it as another file format, such as JPEG.

  10. so if I change my settings in camera by pumping up the contrast and the saturation up it will or will not show up on the RAW file?

  11. Joe,

    You will see the changes when you display the RAW file in your computer because your conversion software displays the color markers as taken. However, the key thing is you can change the contrast or color saturation to any other level and it will be as if you had used that level originally. RAW files are brightness data (B&W) and have stored markers for color that are not applied permanently. Once you save the RAW file to JPEG the color saturation and contrast is locked in place.

  12. Another noteworthy point regarding picture controls for RAW shooters: My understanding is that Picture Controls will affect what you see on your camera display when reviewing images or looking at the histogram of an image. If you bump saturation all the way up, your camera display might tell you that you've blown all the channels, whereas the RAW file is actually ok. This could lead you to underexpose images.

    If you shoot RAW only, I'd suggest turning the picture controls down to Neutral or less, it'll make your histogram information more accurate.