HEIF: Why no Adobe RGB?

I accidentally posted this in the moribund Sony/Minolta forum, but I meant to post it in this slightly more alive forum instead.  Sorry.  I could not find a way to delete the earlier mistaken posts.

Last month I bought a Sony A6700. I still have mostly m4/3 gear and still mostly prefer it, but I was sort of bored and felt like trying something else.

Anyway, I have been playing around with HEIF photos. Sony, Canon, Nikon, Fuji, Panasonic, etc. these days produce 3 types of photo files: raw, 8-bit JPEG, and 10-bit HEIF.

With the A6700 the HEIF choices are: 4:2:2 or 4:2:0.

And you can select among 4 compression levels (same as for JPEG): Extra Fine, Fine, Standard, Light.

With Sony HEIF you can use sRGB or HLG (Hybrid Log Gamma) that uses BT.2020 color, but not Adobe RGB (choice is grayed out). With JPEG you can use sRGB or Adobe RGB.

I wonder why Sony HEIF does not allow Adobe RGB?

I have been playing around with HEIF 4:2:2, Fine, sRGB. Lightroom Classic supports it.

I have been finding several things about the A6700 that not a single written or video review bothered to mention. No surprise. Every time I buy a camera it is the same. 🙂

I have searched and still not found an answer to my question so today I asked ChatGPT. It gave this answer which is just speculation on the reason(s), but good stuff:

The discrepancy in color space options between JPEG and HEIF formats in Sony cameras could stem from several factors:

1. Technical Limitations or Design Choices: It's possible that the implementation of HEIF support in Sony cameras is more limited compared to JPEG. Developing support for multiple color spaces in HEIF format might present additional technical challenges or require more resources, leading Sony to prioritize other aspects of HEIF implementation.

2. Workflow Considerations: Sony might have made the decision based on typical user workflows and preferences. While Adobe RGB is commonly used in professional photography and printing, the majority of consumers may not require it for everyday photography. By offering Adobe RGB only for JPEG, Sony might be catering to the needs of photographers who specifically request this option for certain types of work.

3. Market Demand and User Feedback: Sony may have gathered data indicating that the demand for Adobe RGB in HEIF format is relatively low among their target customer base. If the majority of users are satisfied with sRGB for HEIF images, Sony may choose not to allocate resources to implement Adobe RGB support in HEIF format.

4. File Size and Compression Efficiency: HEIF is designed to offer better compression efficiency compared to JPEG while maintaining high image quality. Using Adobe RGB in HEIF format could result in larger file sizes due to the wider color gamut, potentially undermining the benefits of HEIF's compression efficiency.

5. Compatibility and Standards: While Adobe RGB is widely used in certain professional workflows, sRGB remains the standard color space for most consumer electronics and online platforms. By defaulting to sRGB in HEIF format, Sony ensures broad compatibility with displays, printers, and online services.

Overall, the decision to offer Adobe RGB for JPEG but only sRGB for HEIF in Sony cameras likely reflects a combination of technical considerations, user preferences, market demand, and compatibility requirements.