Embedded jpegs in NEF raw files

Question

I open a .NEF image from my Nikon D80 in the Windows Photos app (the modern/"metro" style app). I then zoom in, and it re-renders or something to display higher resolution, but the colours become less saturated, and the contrast decreases slightly. I presume it first opens the embedded jpeg, then draws the NEF file when I zoom in.

What puzzles me the most is that if I open the NEF in Photoshop and save it as a jpeg, the colours and contrast seem to be in between the first and second (zoomed in then out) previews in the Photos app. Interestingly, the Windows Photo Viewer (desktop app) displays the NEF similarly to the 2nd screenshot, but slightly differently.

So my question is this: why the discrepancies? (Apologies for poorly-worded title)

I have attached screenshots (seen in the Photos app) below:

^ The first preview that opens in the Photos app

^ The second (zoomed in then out) preview in the Photos app

^ After converting into a jpeg

Answer 1

The JPG image embedded in the NEF file is just one way of interpreting the raw information to make a final picture. It is the automatic conversion done in the camera. This is the conversion used to show you what the picture looks like on the monitor in the camera. They have to pick something. Nikon also encrypts the information so that you can't do the same conversion without the decription key.

This in-camera conversion does take the ambient light color into account, so it's usually not too bad, but it is certainly not the single right answer. The automatic process has no idea what parts of the picture are important to you or what you are trying to show.

Some software may do its own default conversion from the raw data, sometimes just because it doesn't do the decryption. In any case, the JPG picture is just meant as a quick basic way to show you the picture, not as your final picture. It therefore doesn't matter what the camera did or what various software programs do. They all fill the purpose of showing you the picture. Beyond that, the JPG picture is irrelevant, as is any other automated preview derived from the raw data. Ultimately you have to decide what you really want and steer the conversion process accordingly.

Answer 2

When you open the embedded jpeg most applications will render it the same because it is already in a standardized format that includes specific instructions on how the data should be displayed. The RAW data in your NEF file has already been converted by the camera based on either the default settings or whatever settings you have selected before you took the shot. The data from the NEF file used in the JPEG has been "baked in" and the rest of the data has been discarded (as far as the embedded preview is concerned).

When you open the NEF file with different applications, each of those applications will convert the RAW data in the file using that application's conversion algorithms and default settings. Most applications will use their own conversion algorithms rather than license the camera manufacturer's so each program is applying a different conversion process to the data in the NEF file.

Most camera makers include a slight boost in saturation and contrast to files converted to JPEG in camera using the default manufacturer settings. Most, but certainly not all, RAW convertors start out with a fairly neutral rendering of the data that some might describe as a little "flat".

There are some RAW convertors, such as Canon's Digital Photo Professional, that open the RAW file using the in-camera settings at the time the photo was taken and the results of the initial rendering will be extremely close to the embedded preview. The big difference is that nothing has been "baked in" and you are free to alter settings to get the result you desire. The vast majority of such programs are those provided by the manufacturer of the camera in question.

Answer 3

I used to shoot jpeg + raw (NEF) just for the sake of original JPEG that comes straight from my Nikon camera. Sometimes I'd prefer the feeling of the original JPEG. I have experienced exactly the same thing as the author above: I was unable to restore a JPEG from NEF using lightroom/darktable to make it look exactly the same as original in-camera JPEG.

Everything changed after I installed opensuse linux 42.1 with KDE. The default picture viewer application, Gwenview, Version 4.14.0, simply does the most amazing thing I can ever expect: it displays the embedded JPEG from NEF just perfectly, with the color profile!! My monochrome picture is displayed as mono! And even better, after a NEF is loaded it can be saved as a JPEG file, which will look exactly the same as in-camera original JPEG, but with a bonus: much smaller size! I guess different algorithms used resulting in file size difference.

So my suggestion: install OpenSuse 42.1 Leap KDE version and try it. You got to use it to believe it. The system is free by the way.

Make sure you install the KDE version rather than the Gnome version, which has totally different viewer application.

Answer 4

As far as I know, Microsoft Windows is not color corrected. Neither are all image viewers today aware of the embedded ICC profiles in images and how to use them to properly render the images on a display.

Some tools will simply flatten the raw pixel data in an 8-bit per channel RGB bitmap without using additional data (white balance, color curves) so no wonder your output will differ across different viewers/converters.