| charlie10 |
Curious. With a split fresnel setup, could we tilt a widescreen LCD ~45 degrees horizontally, without screwing up the focus or keystone?
I'm hoping to build a widescreen projector based on the 1600SW, and wondering if by tilting the LCD I can use regular size fresnels instead of needing the larger 17" ones eg. diylabs.
Ideally the light rays between the fresnels are parallel, so focus and keystone are not affected? Or is that in fact horse-puckey.
The image would definitely be compressed horizontally, requiring an anamorphic lens or curved mirror to correct. I'm not sure how difficult that is...
I saw some prior posts which discuss tilting the LCD by a shallower angle (12 deg.), apparently increasing contrast. Eg.
http://www.diyaudio.com/forums/show...=&postid=256118
I don't know whether the 1600SW panel looks good at 45deg. or not. According to the old SGI ads it has a "wide viewing angle".
- Charlie
projector newbie |
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| Dwiel |
One major problem is that the light will not be entering the LCD at the correct angle. It depends on how drastically you tilt. I am guessing that 45deg will pretty much stop all of the light from going through. It largely depends on the LCD though. If you would simply kile to fix keystone, I suggest you tilt the fresnel between the LCD and the projection lens. It worked for me. I even had it tilted with a pretty large angle and it still produced decent results. The picture was slighly compromised by using this method though. Keep in mind that I was rotating the fresnel probably 25deg.
Hope that helps! |
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