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Discussion Starter · #1 ·
While following a thread on the PLV-70 and using the IMX image processor, I discovered the idea of using binoculars to set focus.


I usually set focus by eye on an image with texture, and I found there was usualy a little bit of play in the focus where the texture looked sharp. But I discover something tonight.


On a bright image, I used binoculars to watch how the pixels changed as I adjusted focus.


I have a panamorph lens on my projector, so the horizontal lines of the DLP pixel are a little less obvious than the vertical lines.


As I adjust focus clockwise or counter clockwise from perfect focus on the pixel edges, I noticed the clockwise rotation began to blur the horizontal edges more first. Then the counter clockwise rotation away from perfect pixel focus began to blur the vertical lines first.


I made an interesting discovery. If I dial the focus counter clockwise ever so slightly so the vertical pixel edge lines just go soft, screen door in the projected image is reduced dramatically yet focus in the image is still sharp. The adjustment is so minor that I can still make out the outline of the pixel in the binoculars, but maybe only half as sharp as perfect zeroed focus.


If I go far enough to cause the pixel outline to completely disappear in the binoculars, thats when the image to the normal eye begins to get soft. But there seems to be a middle ground between perfect zero and out of focus, that enhances screen door while maintaining a sharp projected image.


If I rotate the focus clockwise, the affect is not the same. The horizontal lines drift soft first while the vertical lines remain pretty sharp. If I go far enough to soften the vertical lines, the image to the normal eye is already getting soft.


So counter clockwise focus adjustment does the trick.


Just an observation I thought worth mentioning. Give it a try and see if your projector reacts in a similar manner.


RJ

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PS... I tried the adjustments with a HBO-HD source just to make sure the slight defocus did not soften the HD image. It did not.
 

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Geesh RJ...I'll have to give that method a try I guess. And here I am just putting up a 'perfect pixel desktop' full of text and adjusting focus from there.



Bill
 

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I usually use the projector's menus and focus them in. A scene might be a little out of focus when filmed, the projector menus won't be.
 

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That's what I do, but Bytehovens discovery is very interesting.


Bytehoven,


Does it also mean that the pixels sitting above the electronics in the screendoor area can go out of focus whilst the pixel itslef is 'dialed in' to focus?


I take it the lens mechanism is working slightly different when rotated one way than when rotated the other - any play in the mechanism may be taken up better in one direction than the other.


Just thought - were you trying this on a DLP? I just assumed LCD because you mentioned PLV70...


When you say clockwise/counter-clockwise, is that looking at the screen, or the projector?


Gary.
 

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I thought so - but the PLV70 bit threw me for a minute. :)


Cheers Scott.


Gary.
 

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I've been using the HT1000's Aspect menu which centers up on the screen. I guess the next level will be a telescope. :)


Thx for the tip.
 

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Quote:
I guess the next level will be a telescope.
Blimey Tom, how far back are you sitting?? :eek:


Gary
 

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Discussion Starter · #9 ·
Quote:
Originally posted by Gary Lightfoot
That's what I do, but Bytehovens discovery is very interesting.
It is a HT1000 I am speaking of.


Clockwise or counter clockwise as you look at the front of the projector.


The way the lens blurs the image in one direction or the other is different. You can see using the binoculars, that a counter clockwise is bluring the image more on the horizontal than vertical. And just the opposite when turning the focus clockwise.


I have seen this before in other focusing devices, particularly when I used to focus the individual CRT tubes in a CRT projector. It was often a common practice to defocus the blue CRT in a certain direction that made the blue lines just a tad wider.


I may be test driving the IMX image processor, since it is also handled by the same folks produce the Panamorph. If I do, I'll post a thread on the IMX on the HT1000, with and wthout the Panamorph.


RJ

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