Why does raw to jpg conversion differ in different editors?

Question

I just started using RAW files (to be more correct I set my camera to RAW+JPG). Then I opened the raw file in RawTherapee and without doing any changes I exported it in jpg next to the jpg file generated by the camera. I expected these two files to look the same, but they did not.

The one was a little overexposed and other had changes that I cannot describe. I thought that RawTherapee does not work well.

So then I tried Darkroom. I opened the raw file with Darkroom and exported in jpeg. This file also had a little different exposure compensation compared with the original jpg, and with the jpeg from the RawTherapee.

Then I also tried Photoshop and again got a little different image.

I expected all these editors to produce the same jpeg but they do not. Why is that ? I noticed that for the same raw file, they auto set different values for some of the parameters like exposure compensation, contrast, blacks, and other. Maybe there is some setting that I need to set to tell the editors to produce the jpeg exactly as the camera did or maybe I am missing something ?

EDIT: Inside the metadata of the raw file there is a tag MakerNotes. This tag contains nikon data that is described here: http://www.exiv2.org/tags-nikon.html It has a lot of camera settings that are stored inside the medatada in the raw file. So I tought that the raw editors can read this data and preset the sliders to this values as a starting point.

EDIT: I found this link that answers my question: https://photographylife.com/how-to-get-accurate-nikon-colors-in-lightroom

EDIT: I just found out that if you import canon or pentax raw file in lightroom it looks very close (not to say exact) to the image that you see on your rear lcd on your camera (the image that you expect to see) but this is not the case with nikon because nikon algorithms are proprietary and canon and Pentax gave the algorithms to adobe. So it seems that the issue is purely technical and just for nikon. There is a debate about this here: http://www.dpreview.com/forums/thread/3197480?page=5

Answer 1

You can get different JPEGs from the camera, depending on the camera settings.

In many ways, raw converters are like film developers. It would not be reasonable to expect exactly the same results even from 2 different mini-labs printing the same negative, using the same paper and the same chemistry. But the sole reason for the existence of different film developers is to produce different images.

Every cameramaker changes their in-camera JPEG engine once in a while, sometimes between camera generations, sometimes with a firmware upgrade.

If you are not into reproduction, there is no right or wrong; there is "I like this more", "I like this less", "I do not like it at all",... There are also bugs, like premature clipping of the highlights, wrong black levels, incorrect midtone calibrations, poor colour transforms, ignoring sample variation. Decisions "in bad taste" happen too, (even) with the raw converters recommended by the cameramakers (that includes in-camera converters). Fortunately, off-line converters are rather flexible, and it is not hard to get what you want out of them.

If you happen to like JPEGs out of camera, you can use the recommended raw converter, as MBaz so rightfully points out; or you can try Adobe emulation based on reverse engineering of in-camera results, those are available under "Camera Calibration", in "Camera Profile" drop-down. Choose there something other than "Adobe Standard" and see how you like it.

Answer 2

If what you want is to reproduce the same JPG the camera produces, your best bet is to use the RAW converter supplied by the camera's manufacturer. Each manufacturer has their "secret sauce" to produce distinctive JPGs. Most stand-alone converter, especially open-source ones like RawTherapee and DarkTable, do not have any insight into how each camera processes the RAW files.

Also, the automatic RAW to JPG conversion you're doing just uses each particular software's idea of what the default processing should look like, and their defaults are all different.

RawTherapee (which is what I use) has a number of processing presets you can apply to get slightly different results, such as vivid vs neutral vs subdued color. You may want to explore these and find the one that is most similar to what you're looking for.

Personally, I use a completely neutral preset -- the only processing it does by default is correct lens distortion.

Answer 3

When you take a picture with your camera it makes choices about how to process it. Think of things like white balance, contrast, noise reduction, etc. When it captures a picture it makes those adjustments and saves them as a jpg and throws away a lot of information. When you capture the picture and it is saved as a raw picture there is very minimal processing. Basically, that means you are expected to do the post-processing, so adjusting white balance, noise reduction, etc. So when you decided to export the raw without any adjustments you are exporting a flat unprocessed picture. If you like how your jpeg looks you might not want to waste hard drive space on storing the raw. If your jpeg file needs more advanced adjustments like recovering shadows,highlights there is a lot more latitude so you should be able to improve upon how the jpeg looks. I used to switch raw+jpeg for this reason. I decided to switch to just raw because I found that I was spending a lot of extra time deciding between keeping the raw or jpeg.

Answer 4

I just started using RAW files (to be more correct I set my camera to RAW+JPG). Then I opened the raw file in Rawtherapee and without doing any changes I exported it in jpg next to the jpg file generated by the camera. I expected this two files look the same but they did not.

Very false expectations.

Doing that simply fails to grasp the entire idea of shooting raw. The camera makes adjustments for JPG, such as adding white balance, and adding settings like contrast and Vivid, etc.

But there are no adjustments made to raw files. The whole idea of raw is that it includes absolutely no settings, so that we can choose those settings better after we can actually see the image, when we can see what it needs, and see how well our choices correct it, and maybe try other things too. This is a huge plus, and a big deal, but if you are not going to do that expected processing, then don't shoot raw. The entire point is that the camera does not automatically adjust raw files.

We make adjustments to raw images after we shoot the image, later at home, after we can see what we are doing.

We make adjustments to JPG in the camera, before we shoot the image, and hope it comes out reasonable, sight unseen.

I will offer this: http://www.scantips.com/lights/shootraw.html