We asked camera companies why their RAW formats are all different and confusing

Look at the decoders for each format that darktable supports here: https://github.com/darktable-org/rawspeed/tree/develop/src/l...

It's some binary parsing, reading metadata, maybe doing some decompression-- a thousand lines of C++ on average for each format. These aren't complex codecs like HEVC and only reach JPEG complexity by embedding them as thumbnails!

Cameras absolutely could emit DNG instead, but that would require more development friction: coordination (with Adobe), potentially a language barrier, and potentially making it harder to do experimental features.

Photographers rarely care, so it doesn't appreciably impact sales. Raw processing software packages have generally good support available soon after new cameras are released.

Technically speaking, implementing DNG would be another development activity on top of a RAW export, because RAW also has a purpose in development and tuning of the camera and its firmware.

It is supposed to be raw data from the sensor with some additional metrics streamed in, just sufficiently standardized to be used in the camera-vendors' toolchain for development.

It just "happens" to be also available to select for the end-user after product-launch. Supporting DNG would mean adding an extra feature and then hiding the RAW-option again.

I can imagine it's hard to make this a priority in a project plan, since most of the objectives are already achieved by saving in RAW

...and what do you think DNG is?

In a development environment, this format competes with an already-implemented proprietary RAW-format which already works and can be improved upon without involvement of a legal department or 3rd party.

While having two file formats to deal with in software development definitely "competes" with the simplicity of just having one, patents and licensing aren't the reason they're not choosing Adobe DNG.

--> Your information source is incomplete. Please refer to the license of DNG [0].

The patent rights are only granted:

1. When used to make compliant implementations to the specification,

2. Adobe has the right to license at no cost every method used to create this DNG from the manufacturer, and

3. Adobe reserves the right to revoke the rights "in the event that such licensee or its affiliates brings any patent action against Adobe or its affiliates related to the reading or writing of files that comply with the DNG Specification"

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None of this is trivial to a large company.

First of all, it requires involvement of a legal department for clearance,

Second, you are in risk of violation of the patent as soon as you are not compliant to the specification,

Third, you may have to open every IP to Adobe at no charge which is required in order to create a DNG from your sensor (which can be a significant risk and burden if you develop your own sensor) and

Fourth, in case the aforementioned IP is repurposed by Adobe and you take legal action, your patent-license for DNG is revoked.

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--> If you are a vendor with a working RAW implementation and all the necessary tools for it in place, it's hard to make a case on why you should go through all that just to implement another specification.

[0] https://helpx.adobe.com/camera-raw/digital-negative.html#dng