[clackers]

Einstein showed a century ago that that's impossible

Reh's speculating the distance is longer, not that the speed of light has altered, Paul!

My own speculation about bounce exposure problems across brands is whether the camera algorithms have determined if just a subject is to be illuminated, or the whole scene.

IIRC, Canon used to take into account the current focus distance to attempt to make this metering decision easier, but have changed their mind on this philosophy now.