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Discussion Starter · #1 ·
I can view 4:3 material in VGA, in this case the entire 4:3 projected image is all a viewable picture.

If I use 4:3 mode in SVGA the picture shrinks and there is a faint light border around the image that is the size of the 4:3 VGA picture.

In 16:9 mode I get an accurate 16:9 image with the typical black bars at the top and bottom(2.35:1) but still there is a box of light around this entire image with the black bars that is the same size as the 4:3 VGA picture.


As it is a standard 4:3 VGA picture looks best for widscreen movies because its the only mode where this faint light box does not show up.

This sucks because I just built a 16:9 screen and I really never noticed it on my 4:3 screen , the light is that faint.

I can zoom 16:9 material on my new screen so that the image and black bars (for 2.35:1) all fit on the screen nicely but still I have the faint light shining off the screen on the top, bottom and sides..my wall is covered in felt so it absorbs it very well but I can still see it.


I would figure SVGA would be a larger image since it is a higher resolution, it seems that all of my pixels are being used in VGA mode but not in SVGA.


What's going on here and can I deal with this in any way?


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James' DIY Speakers




[This message has been edited by James W. Johnson (edited 09-16-2001).]
 

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Discussion Starter · #2 ·
As an experiment I hooked up my computer to the projector and in XGA the entire 4:3 image is filled up and SVGA and VGA the picture becomes smaller and has the light box around it...strange, with the DVD player VGA is the largest and SVGA is the smallest.


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What you are seeing is what is commonly referered to as halo. Alot of projectors have it, masking is the only way to minimize it. There are those who have done internal mods to correct this, but I don't recommend trying that yourself. What model projector are you talking about?
 

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Quote:
Originally posted by James W. Johnson:
...strange, with the DVD player VGA is the largest and SVGA is the smallest.
James,

It could be halo, but I am a bit confused. When you refer to 'VGA' and 'SVGA' on your DVD player what do you mean?


These 2 terms refer to computer resolutions, do you mean 'S-Video' on your DVD player instead of 'SVGA'?


Also, what projector do you have and how are you switching between 'VGA' and 'SVGA'?


 

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Discussion Starter · #5 ·
When you refer to 'VGA' and 'SVGA' on your DVD player what do you mean?

>>>>>>>>

My projector has 4 screen adjustments , No, All, VGA and SVGA. these are all usable in NTSC , but not NTSC wide(anamorphic)


These 2 terms refer to computer resolutions, do you mean 'S-Video' on your DVD player instead of 'SVGA'?

>>>>>>>

No I mean VGA as in 640x480 and SVGA as in 800x600...anamorphic mode is locked at 800x480.

What's odd is VGA mode fills the entire screen but SVGA and Anamorphic does not.

When my computer is hooked up to it VGA is smallest , and XGA is biggest which makes sence.


Also, what projector do you have and how are you switching between 'VGA' and 'SVGA'?

>>>>>>

I have a TC2000 .... http://projectorcentral.com/projecto...cfm?part_id=57

the specs at projector central are wrong , I have many more features than what there database says.

Anyways I can switch between VGA and SVGA for DVD playback.


I am guessing that what I see as VGA is actually an XGA for DVDs, it makes sence since the entire pixel structure is being used in this mode, I can't explain it but that's what is happening as far as I can tell.



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James' DIY Speakers


[This message has been edited by James W. Johnson (edited 09-16-2001).]


[This message has been edited by James W. Johnson (edited 09-16-2001).]
 

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James,


-- I am not familiar with your projector, but I can say:


1. What you are seeing is not what people call 'halo' - AFAIK, that is found only on DLPs not LCD projectors like yours.


2. The 'faint light box' that you describe is just the pixels that are 'black' (turned off) and outside the SVGA or 16x9 area.


3. A strong possibility is that VGA is always scaled from 640x480 to 1024x768 to fit the panel, but SVGA is left unscaled. The current Fujitsu projectors specify this and your pj was manufactured by Fujitsu.
 

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Discussion Starter · #7 ·
Actually I think it is the Halo effect as decribed here...

(the Telex 600 is the same as my unit)


(copied from Sterophile Guide to Home Theater)


CALIBRATION


To play standard letterbox (non-anamorphic) material, you must use the NTSC setting (not NTSC Wide). But the letterbox will then appear in the center of the smaller 4:3 NTSC picture. To then fill the screen width with this letterbox, you must zoom the image up, or switch to VGA in the Resizing menu. The first option requires a very long throw distance (lens-to-screen)—my experience suggests at least 18 feet for a 78-inch wide picture. Switching to VGA rescales the image to use the full 1024x768 pixel count of the LCD panel. While you might think that this resizing would increase the quality of the image, SS reports the opposite; the most obvious effect of the rescaling is an increase in visible motion artifacts.


When you do switch modes, you may find that the image shifts on the screen, primarily up or down. Part of the picture may even shift slightly offscreen. There are adjustments in the service menu that can compensate for this—another reason we recommend that an experienced technician set up the Telex for best results.


Because neither the standard NTSC (with resizing off) nor NTSC Wide mode makes use of the full 1024x768 pixel structure of the LCD panel, the image on the screen in these modes will be surrounded by a gray halo. This is from light leakage through the unused pixels, and may be distracting if projected on anything but a black background. It cannot be masked off by the projector.


I do agree that, in my system, the Telex produces some of the best-looking pictures—if not the best—that I have yet seen from an LCD projector.—TJN





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Yep, sounds correct - my definition of 'halo' was a bit off.


The DLPs I've played with have light leakage outside the the panel, not just from unused pixels. I've been thinking of that leakage as 'halo'.
 
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