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Discussion Starter · #1 ·
Am I really seeing scanlines? At least thats what it looks like in the center of my 119" wide screen.
 

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Originally posted by Scot Kight
Am I really seeing scanlines? At least thats what it looks like in the center of my 119" wide screen.
Just back up a little, then the scan lines will disappear:D
 

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I think he is bragging guys.


Brian
 

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I think he is bragging guys.
I think he's suitably excited and deservedly proud about the exceptional performance he's getting from his able setup and tweaking skills.


Um, yeah, he's bragging.


After he finishes learning on his set up, I'll let him work on mine so he can brag about those improvements too!
 

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I intentionally leave my CRT slightly defocused to soften my scanlines.
Clarence,


Intensionally defocusing the CRT is not a good idea to get rid of scanlines. Defocusing will not only close the scanline gap in the vertical direction, but also take out the snap in the picture in the horizontal direction.


A better way to do it, is changing the beam shape with astig to a bit of a vertical elipse. That way you get rid of the scanlines, yet have perfect horizontal focus.


While doing this, one has to be careful that astig and e-focus interact with another, so this has to be done in an iterative way:


1. use astig a bit to get a slightly vertical beam shape

2. adjust for perfect 'horizontal' focus with a test pattern that has high horizontal frequency response (e.g. horizontal burst)

3. judge scanlines structure from seating position

4. if still visible, go back to 1.


Maybe you meant doing it like this, but the way you described it made it sound like you would use optical or EM focus, which by no means the way to do it.


Regards

Bjoern
 

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Intensionally defocusing the CRT is not a good idea to get rid of scanlines
Sorry. That was supposed to be a sarcastic self-demeaning jab at my focusing skills, which are likely much weaker than Scot's.


"Yeahhh... that's the ticket!" is an old SNL character voice from a liar who provides excuses and exaggerations to cover his own miserable life.


-Clarence
 

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Ah, you got me there :D


I didn't think you were joking because it IS a common practice to decus (through means of astig) the image to get rid of scanlines for resolutions like 480p, 576p and 1080i on 8" EMF and 9" CRTs and even at 720p and 864p with the best 9" CRTs.


Those jokes based on american show stars and such always fly right by us europeans :p


Cheers!
 

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Discussion Starter · #9 ·
Haha no I am not bragging. I am truthfully just trying to figure out if what I think I am seeing is correct.


Now that being said, my side to side focus isn't quite what I would describe of as exceptional just yet, or even good. Major work remaining there. Setting the astig made a huge difference in the center focus though, still need to touch up the green astig, but moving all of the cables around is not on todays schedule...


I think whats letting me get the most from the projector at the moment is it is sitting on a wire rack pointed straight at the screen. No lean angle at all (so technically the back end of the projector is jacked up. Makes setting the geometry a peice of cake :D Also lens aberations are kept to an absolute minimum.
 
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