DNG files darker than original RAW files - and white balance mismatch

Question

I've recently dabbled in RAW to DNG conversion and noticed that the brightness of files converted from RAW (Fuij raf) to DNG via Adobe DNG Converter does not match.

There's an exact 1/2 stop difference, the DNG files are darker.

After looking at the Adobe forum this seems to happen with a lot of cameras/raw files but there's not real explanation except for some assumptions. I think it's because some camera manufacturers want to artificially protect the highlights and boost the dynamic range by underexposing - which is then compensated by the software interpreting the RAW file.

Maybe there's some aspect of the original RAW file that does not get properly "translated" when converting it to DNG so the +0.5 stop compensation (in this case) does not register.

Would it be possible for the DNG Converter to compensate for that? To - in essence - add 1/2 stop in exposure or rather to set this as a general value? Or would that potentially clip highlights and reduce the (artificially boosted) dynamic range?

EDIT: I've also noticed that the white balance is off. While the "unedited" visual white balanance is identical, the numbers are different.
For example: the original RAW file has 5940K and -2.8 Tint
The converted DNG has 5462K and 0 Tint.

But both look the same (apart from the exposure difference)

Naturally that makes it very difficult to properly match the white balance between RAW and DNG. I'm not sure what that would happen.

D Fosse · Answer

The question is where are you seeing this, what are you comparing? Are you comparing a RAF opened in ACR, with the same file converted to DNG opened in ACR? You need to show screenshots, and include the application interface so we can see what is what.

If the RAF has metadata in a sidecar file (xmp) after you've processed it, that same metadata will be inserted in the file header in the converted DNG. There is nothing in the DNG converter that can change this.
If the RAF is unprocessed there won't be a sidecar file, and it opens in ACR at the default settings. And when you convert to DNG, the file will again open in ACR at the default settings. In other words - identical and the same.
The DNG converter can not change the sensor data. It's just packaged differently.

A general comment about temperature and tint numbers. These, contrary to popular belief, are not absolute numbers. There is nothing that measures the color of the actual light in the scene. These numbers represent the amount of correction needed to produce a neutral-looking result.

With different raw processing engines, different corrections, different calculations, will be required to produce the same neutral-looking result.

So these temp/tint numbers will in fact never match between ACR/Lightroom and another raw processor, such as the one in the camera firmware. Or any other raw processor. They will all have different numbers, even when looking roughly similar. That is normal and expected.

As for brightness - camera manufacturers will usually push this as far as they can, to produce the brightest result from the existing sensor data. This simply makes it more appealing to a potential customer in the store - the brighter, the "better". ACR doesn't do that, it doesn't need to sell cameras. So it's more conservative. That's why a camera-processed file will nearly always look brighter than one opened at default settings in ACR.

The point is - it's the very same sensor data! Nothing is really brighter or darker. It's just the Exposure setting in the raw processor/camera firmware. Push the slider in ACR, same result.

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