Originally Posted by Ken Ross
Owen, you actually should get a pretty big jump in resolution. Forget the screen shots. Your Hitachi RPTV probably has 7" guns. With that arrangement you're generally lucky if you can get 1400 lines of horizontal resolution. You need a RPTV with 9" guns to even have a shot at the full 1920X1080 (and that's assuming perfect convergence, focus etc.....not very likely). So the Panasonic will give you the full 1920X1080, which will represent a nice jump up in horizontal resolution.
Now of course the subject of source comes up and if all you do is watch Directv, you'll gain nothing since D* doesn't do 1920X1080 anyway. But if you watch HD DVD, that's another story.
In theory what you say is accurate, however in the reality there are many complications.
As far as CRT RPTV's are concerned, there is more to resolution then tube size alone.
Raster size, beam spot size and the bandwidth of the driving electronics all have there part to play and all three need to be adequate to provide high resolution.
My modified Hitachi has 7 tubes, but has had the CRT's relocated closer to the mirror to remove overscan and allow a larger then standard raster size.
It can easily display a one pixel wide vertical and horizontal lines at my HTPC's resolution of 1712x1080 with no overscan. The virtual lines are almost as bright as the horizontal lines, so the bandwidth of the driving electronics is up to the task.
The thing is that 1712x1080 is actually plenty for 1080 HD video, as no 1920x1080 video has 1920x1080 visible resolution.
Digitized video has strict Nyquist limits and is filtered accordingly to avoid artifacts above the Nyquist limit of 960 horizontal, and that is before video compression degrades it further.
Lenses on HD video and even cinema film cameras have very significant limitations that mean 1920x1080 resolution (fully resolved) is unattainable.
Sonys top range studio 1080 video cameras, fitted with the best available lenses, have an MTF of only about 45% at 800 horizontal, and little more then 10% at 1400 horizontal, which is considered the maximum usable resolution of those cameras.
An MTF of 45% means that pixel to pixel contrast is only 45% at the specified resolution, so at 1400 horizontal a typical 1920x1080 HD camera will reproduce an alternating black and white line pattern as 5% white and 5% black, which is not exactly impressive now is it.
Film sources can be better, as they can be digitizes at much higher resolutions, like 3840x2160, or double 1920x1080 to alleviate the Nyquist sampling limit.
However film stock and lens performance in cinema cameras is still a significant limitation, so that fully resolved 1920x1080 resolution (100% MTF) is not possible.
The best one can expect from film is around 1700 horizontal, and with a low MTF of less then 50%.
BluRay and HDDVD are still heavily compressed formats that will degrade the resolution of the master, so 1920x1080 visible resolution is a myth in practice, and is not even available from the master.
The only single pixel detail available in video is the sharp edges of compression artifacts, and there is no advantage in reproducing those faithfully.
So, for video playback, a digital 1920x1080 display has little practical advantage over a good 1080 CRT RPTV.
PC text and graphics will be sharper on a digital model, but video is a different story.
Image sharpness and detail are also not the same thing. Low resolution displays can be very sharp and high resolution displays can look quite soft.
Sharpness has more to do with contrast then resolution.
The issue of resolvable detail in 1920x1080 video source is widely misunderstood in this and other forums.
People wrongly assume that because video has 1920x1080 pixels that it also has 1920x1080 visible resolution. That is simply not the case.