Originally posted by StooMonster
Interestingly, with the series 5 Panasonics it's possible to edit a setting in the service menu to automatically refresh PAL and NTSC at double rates of 100Hz and 120Hz, however, in this mode the greyscale depth drops to 8-bit.
Okay, read around a bit and did some research. Panny5 plasmas have 50Hz and 60Hz internal frame buffers and the above works; for the SD versions that is.
The HD versions of the Panny5 -- like my 50" model -- run a double sample rate frame buffer of 100Hz or 120Hz all the time, and keep the colour depth.
So what KDB4 says about frame buffers may have some element of truth, however, the numbers are apparently incorrect.
Can we test this?
An example of "tearing" is where one sees a picture broken up because a vertical refresh can not keep up with the physical output of a graphics card. One commonly sees this in computer games where a PC may be capable of outputting say 180 frames per second, but the vertical refresh is set to 60 Hz, without vertical refresh lock set when there is signficant movement the screen with tear into three sections 180/60 = 3. If the vertical refresh lock is on the picture will display 60 frames per second because it is locked to the output; and you waste all that lovely rendering power. Only lamers leave their games running at 60Hz.
So, how can we utilise this to test that screen is not locked to 60Hz? We run a game that my PC can generate say 100 frames per second, we set graphics cards vertical refresh rate to 85Hz and set the vertical refresh lock to on; thereby limiting and locking the output to 85 frames per second.
If the screen were locked to 60Hz internal frame buffer the effect of playing 85 frames a second with rapid movement would generate "tearing" in vertical lines. If there is no tearing the screen has either a higher refresh rate than 85Hz or is displaying 85Hz.
Perhaps one could argue that the frame buffer is sampling only a few of the entire frames presented to it, but this would result is stutter and judder.
Result of EA's "Battlefield 1942" running at 85Hz with vertical refresh lock selected, not one tear or stutter, silky smooth. Same with 75Hz, 72Hz; I'm going to see if I can run UT2003 at 100Hz later and see if I get any tearing then.
Therefore suggesting that my research at the beginning of this post was correct, and this screen does not appear to have an internal frame buffer of 60Hz more like one of 120Hz.
Hrm... we like science: theorise, experiment, conclude.
Back on topic...
Therefore it's going to be very interesting to see how iScan HD performs with 3:3 at 72Hz and 75Hz on this screen.
Stuart
PS: Don't know what the deal is with any other brand of plasma or generation of Panasonic, this is UK Panasonic 5 series.
PPS: still reading though service manual.
I get the same results as _Sin