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jeffslife
Joined: 17 Apr 2010
Posts: 4190
Location: ohio usa
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| Posted: Thu Sep 30, 2010 10:49 pm Post subject: will maxing raster change picture quality? |
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Well I took curts advice and started my setup over.
I watched graham johnsons set up dvd twice
and read the manual twice at least ( I still have issues with it though)
After resetting everything to 128 and cleaning the lenses
I noticed the raster is about 3/4 of an inch away from the left and right (19.05 mm)
and about a half inch from the top and bottom(12.7mm)
from what I could tell on the dvd the raster should be about 1/4 inch(6.35mm)
from all edges. Is this correct ?
If so when I maximize it will it go into areas of unused phosphur
and show up on my picture ?
The tubes are nice about 1500 hrs.
If that is the case how long will it take for the phosphur to match
or will it always be brighter around the edges.
I have a 4x8 16:9 picture now.(1219.2 x 2438.4 mm )
although not even close to quality yet.
soon I hope.
I am going no farther on this set up until I know.
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Artinaz
Joined: 15 Jun 2009
Posts: 110
Location: SF Bay Area
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| Posted: Thu Sep 30, 2010 11:23 pm Post subject: |
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Is it on the floor where you can easily change things ?
I would max the raster and check on my screen if the uneven wear shows up on bright scenes or on a full white screen. If you are adventurous, you can try evening out the wear on the unused parts.
With a maxmised raster, the tubes will wear less, you will get a brighter picture, so you can turn down your contrast. Remember that the throw will change as you change the raster size. Also, check your raster size at the resolution you plan to use.
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jeffslife
Joined: 17 Apr 2010
Posts: 4190
Location: ohio usa
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| Posted: Thu Sep 30, 2010 11:29 pm Post subject: |
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No its mounted on the ceiling but I can move the screen to
change the throw
I do not know how to check the raster at 1080i
I was using the internal test pattern
I have an avia dvd I geuss the bd upscales it
to 1080i Would that work?
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jeffslife
Joined: 17 Apr 2010
Posts: 4190
Location: ohio usa
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| Posted: Thu Sep 30, 2010 11:57 pm Post subject: |
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Well I think I am legally blind now but
I put in a bd that has test patterns on it
and it appears to be even smaller than
the internal test pattern
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dvh99
Joined: 25 Dec 2009
Posts: 2158
Location: nederland
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| Posted: Fri Oct 01, 2010 12:09 am Post subject: |
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the tubes are 4:3 so if you maximize horizontal and vertical the 16:9 image will be out of proportion.
the vertical size raster should be set in a way so the proportion to the horizontal width is right.
for instance the hor raster is 16cm width on the tube then the vert raster should be 9cm and not 12cm.
not exactly of course because porch settings are more horizontal.
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jeffslife
Joined: 17 Apr 2010
Posts: 4190
Location: ohio usa
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| Posted: Fri Oct 01, 2010 12:21 am Post subject: |
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ok, well that explains the HUGE difference between the internal test pattern
and the pattern off the bd.
so should I maximize the HOR raster
and then change the VER to get to 16 9
It would appear that i will be shrinking the ver raster
and using even less surface area
ok?
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dvh99
Joined: 25 Dec 2009
Posts: 2158
Location: nederland
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| Posted: Fri Oct 01, 2010 1:44 am Post subject: |
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yes that is correct
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jeffslife
Joined: 17 Apr 2010
Posts: 4190
Location: ohio usa
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| Posted: Fri Oct 01, 2010 2:26 am Post subject: |
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well if my math is correct and these days thats not a given
A true 16:9 ratio screen would be 54x96 inches
I got the 96 without getting into the unused phosphur
and the 54 is no problem either
the question is should I obtain the 54 by shrinking the raster or
by adjusting the rgb size
is there an advantage?
also should I max out the HOR raster
and then use rgb size to bring it out of the unused
phospher area or leave the HOR raster where it is
at 96 and NOT in the unused phosphur
I know to you guys these are dumb questions
and I am not trying to waste your time
just trying to understand.
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dvh99
Joined: 25 Dec 2009
Posts: 2158
Location: nederland
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| Posted: Fri Oct 01, 2010 7:14 pm Post subject: |
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ok, here goes.
diagonal stripes is the 4:3 raster
yellow is the active image in the 4:3 raster.
blue = back and front porch horizontal that do fall in the raster and since you need lots of backporch and a little front porch at higher scanrates its advisable to shift the raster to the left to get the active image centered on the tube face , this can be tricky.
purple is the front and back porch vertical but since you need very little front and back porch vertical the way it is drawn now you are wasting lots of bandwidth.
you have to decrease vertical porches to say (vert backporch=30 vert front porch=10)
by decreasing the porch settings vertical the way it is now in the picture the active image will be stretched vertically so now you have to alter vertical raster size to get a good proportion.
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jeffslife
Joined: 17 Apr 2010
Posts: 4190
Location: ohio usa
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| Posted: Fri Oct 01, 2010 10:21 pm Post subject: |
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Thanks
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ecrabb
Forum Moderator
Joined: 13 Mar 2006
Posts: 15909
Location: Utah
TV/Projector: JVC RS40, Epson 5010
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| Posted: Fri Oct 01, 2010 10:22 pm Post subject: |
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Love the drawring!
SC
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AFryia
Joined: 09 Mar 2006
Posts: 965
Location: S.E. Michigan VPH-G70Q
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| Posted: Sat Oct 02, 2010 5:09 pm Post subject: Re: will maxing raster change picture quality? |
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| jeffslife wrote: |
from what I could tell on the dvd the raster should be about 1/4 inch(6.35mm)
from all edges. |
Sounds about right. You will want to figure out your raster size so you can then set your throw distance. PJCalc does not work well with maximized rasters.
With no sources connected I setup initial registration using internal oscillators P2, P3, P4 maximizing the Raster to 4:3. Then converging the sources I adjust R,G,B, SIZE for the image aspect ratios.
The areas picture quality and geometry will suffer the most are the corners. But on a 4:3 tube displaying wide screen aspect ratios you will never use the corners (2-PJ blends aside). Now I'm assuming you are setting up for constant width 16:9. where all video is within the 16:9 screen (some assumptions here).
For that reason I only adjust geometry and convergence for that part of the raster within the 16:9 screen. The less electronic adjustments you make the more stable the image.
Best advice is to work through a complete registration, convergence and calibration start too finish. Don't worry about getting it perfect. Then do it again from scratch. Then perhaps again. It's an iterative process and when you are trying to get somewhere it makes more sense when you know were you are going or where you want to end up.
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jeffslife
Joined: 17 Apr 2010
Posts: 4190
Location: ohio usa
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| Posted: Sun Oct 03, 2010 11:34 pm Post subject: |
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Thanks for the advice
At the rate I am going the third time I will be in my seventies.
Makes sense to me though, hopefully I will get faster as I
understand why I am doing what I am doing and learning how to do it.
I really appreciate your input.
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perisoft
Joined: 29 Aug 2007
Posts: 2920
Location: Ithaca, NY
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| Posted: Mon Oct 04, 2010 6:36 pm Post subject: |
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| ecrabb wrote: | Love the drawring!
SC |
Seriously, that's the most awesome diagram ever!  I'd probably have paid more attention in math class if they'd used stuff like that...
...mainly because I spent my time seeing looking at the illustrations and seeing how they did gradients (linearly scaled circular gradient doesn't look right for spheres...), figuring out how the two color process worked for pesudo-color renderings, and determining reasons for the various conventions they used for tick marks, fonts, and so forth.
There's a reason I did badly in math...
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donnad
Joined: 14 Mar 2006
Posts: 12
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| Posted: Tue Oct 05, 2010 12:56 am Post subject: Re: will maxing raster change picture quality? |
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| AFryia wrote: | | jeffslife wrote: |
from what I could tell on the dvd the raster should be about 1/4 inch(6.35mm)
from all edges. |
Sounds about right. You will want to figure out your raster size so you can then set your throw distance. PJCalc does not work well with maximized rasters.
With no sources connected I setup initial registration using internal oscillators P2, P3, P4 maximizing the Raster to 4:3. Then converging the sources I adjust R,G,B, SIZE for the image aspect ratios.
The areas picture quality and geometry will suffer the most are the corners. But on a 4:3 tube displaying wide screen aspect ratios you will never use the corners (2-PJ blends aside). Now I'm assuming you are setting up for constant width 16:9. where all video is within the 16:9 screen (some assumptions here).
For that reason I only adjust geometry and convergence for that part of the raster within the 16:9 screen. The less electronic adjustments you make the more stable the image.
Best advice is to work through a complete registration, convergence and calibration start too finish. Don't worry about getting it perfect. Then do it again from scratch. Then perhaps again. It's an iterative process and when you are trying to get somewhere it makes more sense when you know were you are going or where you want to end up. |
This is what confused me in the manual. When you setup your initial registration for 4:3, do you use the horizontal width of the 16:9 screen or the vertical height. For example, if your 16:9 screen is going to be 8' x 4'6", do you setup the initial 4:3 to 8'x6' or 6x4'6". Page 15 of the installation manual seems to point to using a smaller screen width when doing the initial setup.
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AFryia
Joined: 09 Mar 2006
Posts: 965
Location: S.E. Michigan VPH-G70Q
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| Posted: Tue Oct 05, 2010 7:06 pm Post subject: |
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Keep in mind when the manual was written wide screen format sources were new so the manual does not do a good job addressing that type of setup.
I initially setup 4:3 to the screen width. The internal test pattern is off the screen top and bottom. So what I do is get white cue cards taped to the back of 1" styrofoam blocks above and below the screen, I put one in each corner and center. This puts the cue cards at the same focal plain as the screen. I set the all the registrations 4:3 except for ZONE, No need for ZONE here, then copy to all memories.
I rarely view 4:3 material, and if I do I use the dynamic stretch feature in Media Center making it 16:9.
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donnad
Joined: 14 Mar 2006
Posts: 12
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| Posted: Wed Oct 06, 2010 12:53 am Post subject: |
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Thanks. That's the way I did it but it was a little easier as my screen is 4:3. I have to white strips of screen top and bottom when I project 16:9
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