I am considering a Samsung 67" DLP set (viewing distance 11') and have a general question re: DLP's. I saw the tv's (it and others) on display and there is a bright horizontal portion of the picture that moves up and down as the viewing position moves up and down. So at eye level, then bright area was straight across the middle third of the screen.
Is that a normal effect of DLP's or were the tv's just set up too bright in the store? (I didn't think to make adjustments to the picture while I was there)
You should compare the LED models vs. lamp models side by side too. I think the lamp models lessen this effect but as Darin says it is inherent in current RPTVs. Don't ignore the Mitsubishi models either, everyone has their own preference so scrutinize all DLPs. Once you set one up properly in your viewing area and get your seating at the right level you hardly notice this unless you keep bobbing your head up and down.
I sit with my eyeline 1/4 up from the bottom rather than the recommended half-way up...
...on occasion I see a bit of darkening (vignetting) at the top, but not unacceptably so...many scenes intentionally included such vignetting...it's a class style in photographic printing...in any case, I sometimes watch lying down on the couch, with my eyeline at the bottom of the screen, and am still happy with the image on my 50A650 set...
It's a good thing you don't watch TV on a trampoline
Seriously, I have the 61" model and I haven't ever noticed this at all. I know its visible when you bee-bop up and down looking for it, but during normal seated viewing there is nothing to worry about.
The high gain screens used by the vast majority of RPTVs do definitely induce uneven brightness... there will always be a "hot spot" of high brightness that follows the line between your eyes and the point of projection. But your eyes do tend to "adjust" to it, and for me, it only becomes noticeable when I move. This is a bigger issue with some sets than others. When I was shopping, I was choosing between the current Mitsubishi sets, and the LED Samsungs. I felt the Mits had more even brightness than the Samsung. But I didn't look at the bulb-based Samsungs... it may simply be as Quentin said... more with LED than with bulb, rather than more with Samsung than with Mits. They may be using higher gain screens on the LED models to maximize the apparent light output.