Bit perfect arw to tif conversions

I want a tif from a sony a7rv with no bit changes at all for some technical analysis of TV light levels. Are there appropriate settings in dxo so the 10bit values from the sony are exactly represented as taken in the 16bit tif export without any scaling or non-linear transform?

You might want to check out RawDigger. It’s an app that can be licensed to provide different levels of analytical capabilities.

Anyways, data in a raw file is monochromatic. Colour only comes with the the conversion to rgb. If you want to see how raw looks as a monochromatic, best resolution image, try this:

Well generally this can be a bit of a problem. Most cameras that shoot raw don’t shoot 16-bit, but lower than that and than the raw converter such as Adobe works inside the 16bit container. This is probably the true for DXO but I can’t be sure. Hence when you shoot raw, soon as you start working with the raw inside converter you are working with larger container. This does not mean you are loosing data per se, but its not one for one accuracy. Usually it does not matter.

If you want to convert from raw to 16 bit tiff , probably you will not get the same data as camera captures, but that’s just how it works.

As far as I know there is no way to shoot 10-bit on Sony a7RV

TIFF (8 or 16-bit, depending on the input image)

TIFF is a format which guarantees a high quality non-destructive workflow, best used for corrections and retouches that do not require the original RAW data. When you choose TIFF format for an output image, you have to select the following:

With or without compression: We advise the uncompressed option. The output files will be larger but you will be able to open them in all image processing software, unlike compressed TIFF files.

8 or 16-bit encoding: 8-bit encoding only allows 256 levels per color channel, compared to 65.536 in 16-bits. Of course, the choice is only made possible if the source image is 12-bit or 14-bit (RAW files), or 16-bit (TIFF files). We advise you to choose 16-bit encoding to maintain the highest possible quality workflow.

Sony a7IV I think has lossy compressed format if you want to shoot Raw in burst mode at the highest frame rate, and drops to 12-bit mode. Lossless format in raw I think its 14 bits. RAW converters usually work in 16-bit, but I’m not sure if DXO follows the same convention.

I don’t think you can shoot at 10-bit.

As for DXO export options. These are from the manual.

Basically you can shoot with Sony 12 bit lossy RAW or 14-bit lossless raw. When working with RAW in DXO or Camera raw probably they will work in a larger container, 16 bit, I know that is how Adobe works, so I assume DXO does the same. When you export from DXO in TIFF you can choose 8-bit or 16-bit. Choose 16-bit, that will ensure least loss of data, but it won’t be real 16-bit of raw data, because Sony camera and most cameras do not capture in 16-bit raw.

If you really want raw raw and you’re doing some technical analysis you may want to think about uncompressed raw and extracting the bits yourself. Not sure how to do it myself but if it’s really uncompressed you may be able to shoot some test files to try to figure out how the data is structured.

I doubt any tool outside of raw digger is gonna be able to give you the real raw dataset without any kind of attempt to debayer the image.

Monochrome2DNG can, as well as DCRAW, which has sadly been left as is for a while.

I searched for the specs of this Sony but the bit depth in raw is 14 bit. The 10 bit value is referring to video.
A lower bit value can be translated in a higher bit value but the steps will be that of the lower bit value. Just for comparing it will not give you a higher precision. In editing it will give you some advances.


a lot of tools can do this - RPP raw converter, dcraw can dump, MATLAB / OCTAVE can read ( directly or after conversion to /non-linear/ DNG ), etc, etc

Platypus was right. RawDigger ($40) will convert Linear RGB from the Sony to Tiff with 14 bit resolution (16K steps) in a 16bit tiff. I was able to load that into my Maxim/DL astrophotography software and average the frames as desired. What I was trying to do was to compare readings taken of my LG OLED at near black to the readings from my i1Display Pro Plus colorimeter to see if they were similar near-dark (which they are). Thank you all for the advice.

Dcraw or the example programs from libraw seem more suited.

To get your values as is in raw , you need ‘no look’ (completely linear response), no camera calibration what so ever , no white balance (so everything is green).

DxO will default to ‘as shot’ for example when white balance is disabled , which is absolutely NOT the same as ‘no white balance applied’.

Rawtherapee and/or Darktable can do it as well.

But you always get things likeraw black levels and scaling from 10/12/14 bit to full 16bit rgb values.

The libraw example programs have a tool ‘4channels’ which extract the r, g1, g2 and b channels of your raw to separate tiff files. With the option to do no black levels scaling.i think this also leaves the max values alone. (So a 10bit recording will yield at most a value of 4095).

Question back : arw file is sony right ? Is there a model and mode that is 10bit ? I only know that they sometimes switch back to 12bit in certain modes / settings but are 14bit otherwise.

What do you mean with this?

That’s 5400K when I’m right.


Images like this: Highlight recovery - #12 by platypus