First, since nobody has mentioned it, the U.S. update (Oct. 6th 2009 release) has no effect on the dimming issue. In fact, I'm not noticing any changes at all. (Hey, Samsung, how about some release notes...and how about an web-based update on the TV I paid $$$$ for so I don't have to download from the web to a USB drive first?)
So, obviously Samsung didn't listen to its customers -- at least not in the most recent firmware release.
Now to the specific dimming issue, and this is particularly addressed to the Samsung person on this thread:
Had I known how bad this issue is, I'd have never bought the TV. Never. I've had the TV for 3 1/2 months now and it is not something you can get used to -- it's every bit annoying today as it was originally. Had the TV not been so expensive, I'd drop kick it out my window and go and buy a Sony.
Everytime a show goes to credits (mostly black screen), cuts to a commercial w/ a black period with only the TV's logo in the lower-right, goes to a dark scene (FREQUENT in many shows, especially ones like the new Stargate Universe, X-Files reruns...heck, lots of shows and commercials), after about 1/4 second the screen dims and looks terrible....and the change itself is very, very annoying and distracting, let alone how much worse the darkened picture is. (If I press "info" on my cable box, so it pops up a light area, then the screen brightens to its normal level.)
I can say without a doubt that I'd be far, far, far less annoyed and distracted by seeing the relatively minor lighting unevenness (spotlighting) from the backlight than the current behavior of the entire screen going dim.
PLEASE give us -- YOUR CUSTOMERS -- a menu option to disable that auto-dimming "feature" (bug, in my eyes).
I'd also like to see a dynamic contrast setting that is about half way between off and the lowest setting, because sometimes even the lowest setting is enough to wash out details on the screen, which is why I generally have it turned off. (Another "nice" but generally unusable feature I paid megabucks for.) This complaint, however, pales in comparison to the horrible auto-dimming "feature" (problem/bug).
To others in this thread, is the "service" menu option a viable alternative or does it (as I've heard) cause the TV to turn off every time there's a brief fade-to-black? And if viable, how do I get to that menu?!