Originally Posted by cawgijoe
The "halo" effect is mostly noticeable when there is a black background with bright areas......say a star field in space or at the end when the credits roll........you may see a bright star against a black background that has a "halo" of light around it. To me this is an extremely minor issue. You will rarely see this in most program material.
Here is a quote from Home Theater Magazine from their review of the LG Infinia 8500 47" set:
"Local-dimming HDTVs have a tendency to create halos around bright objects in otherwise dark scenes. Joel Silver of the Imaging Science Foundation (ISF) has dubbed this the Tinker Bell Effect. It increases as the number of separately addressed LED clusters that make up the backlighting decreases. With most material, this was not an issue on the LG. But in the star field at the beginning of Stargate: Continuum, several of the brightest stars were surrounded by a hazy but clearly visible glow. "
As to auto-dimming.....I think you are referring to the ability of the set to automatically respond to room lighting conditions. If the lights are bright in the room, the set compensates by becoming brighter.......as it darkens, the set darkens. Some people like this feature. I would not use it, but that's up to the individual. It's a convenience feature that compensates for ambient light. Some sets have a "nightime" and "daytime" mode.
Does the halo effect also apply to large bright objects? I can see how this might be annoying. If it's just small letters or stars, maybe it wouldn't be bothersome. But if a halo appears at any high-contrast edge (of an object of any size), that's another story.
And nope, auto-dimming does not refer to the Ambient Light Sensor. On my XVT370 it was a backlight default setting in Advanced Video called Dynamic Contrast Ratio. You could set the Backlight to OFF, DCR, or OPC. "DCR (Dynamic Contrast Ratio)
improves the black level performance and increases contrast ratio," says the manual.
What it actually does is dim the backlight when it senses a lot of dark in the picture. It's a fake way to make the viewer think the TV has better blacks than it does in fact. Unfortunately, it causes dimly lit objects to just disappear! And it dims the rest of the picture as well (although to the eye, brighter objects aren't as obviously affected). This is what people were screaming at Sony about a while back, because you couldn't turn off this feature. A guy at Best Buy told me that Sony got a log of returns because of this, and finally came out with a firmware fix.
Now, what I find in the XVT423/473 manual is something called Smart Dimming. This may or may not be the same thing.
What is Smart Dimming?