What are propcases 196 and 269 (DIGIC III)?

[LjL]

I'm looking for property cases and locations in my A720IS that may contain real-time information about scene brightness.

I've only come across PC 196 and 269 while searching for propcases that clearly change dynamically.

196 definitely appears to be brightness-related, yet it's weird enough, sometimes going back to 0 even when the scene is well lit.

The wiki claims that 269 is the while balance value, and that's fine, except that it seems to semi-consistently change when tilting the camera, even with the lens completely covered. Why would that be?

[cyril42e]

196 definitely appears to be brightness-related, yet it's weird enough, sometimes going back to 0 even when the scene is well lit.

I had interpreted 196 more as related to contrast or dynamic range, but didn't linger on...
I'm just thinking that if it is proved, it could be used to create automatic HDR scripts... edit: that's stupid

[LjL]

You're certainly right it's contrast / dynamic range and not brightness.

Stupid... why, it might be handy for an automatic script. It tells (maybe) just how much you need to bracket. Surely, you can find out by looking at the viewport (zebra-like), too, but what's stopping this from being an easier way, once we know just what exactly it means?