Just brought home a LN55B650 after using a LN46B650 for a month. Thought I would just make a good thing bigger. What a mistake. The 55" does not use the same LCD panel as the 46", and is terrible as far as off-angle / flashlights / blue-blacks go.
I just watched a 1080i movie in the dark and could not get over the brightening of everything at either side of the screen, anything not dead center. And yes, I know how to "calibrate" it -or rather how to set it nice and dark, with blacks as black as can be, with no crushing. (Movie mode, backlight 4, brightness 44, no gimmicks turned on)
The 55" is much worse than the 46" at slightly off angle. Looking at the 55", dead center, 10 feet away, in the dark, you see 1/3 of the left and 1/3 of the right is lighter. Unbelievable.
Then I read on this forum about the different panel technologies Samsung uses in different models, and sure enough, the 55" is NOT the same panel as the 46" - the 46" is made by Samsung (S-PVA technology) and the 55" is made by CMO (not S-PVA technology).
I'm a digital photographer, and a "pixel peeper" - so I even remember the shape of the pixels: square on the 46", s-shaped on the 55" and much more dead space/black space between them.
It's going back.
I understand the 52" B750 has the better S-PVA panel. I'll give up 3 inches for better off angle viewing. All four of us need to watch movies in the dark
