hey guys this is my fist post so be kind. my dumb question is to the lenses you guys use on your diy pj's have focus rings on them or does everything have to be built specific to the room and placement of the projector... if you move the projector do you have to rebuild it to refocus it or what... just wondering cuz i haven't seen anybody talk about it.... i'm planning on doing a full diy projector setup for about 300
using a 400W Mh bulb with 400 ballast
a cheaper LCD projector panel (prolly a Nview z series)
and this lens http://www.surplusshed.com/pages/item/l3003.html
any ideas of what fresnel i should use... i'm going to try and scrap one from a broken OHP or something.
if you have any advice for me i'd love to hear it... thanx in advance
using a 400W Mh bulb with 400 ballast
a cheaper LCD projector panel (prolly a Nview z series)
and this lens http://www.surplusshed.com/pages/item/l3003.html
any ideas of what fresnel i should use... i'm going to try and scrap one from a broken OHP or something.
if you have any advice for me i'd love to hear it... thanx in advance
Broken,
you may have trouble finding a fresnel to use with this lens because of it's short focal length. I'm guessing 240mm to be about nine inches or so but you could probably use the diylabs fresnel combination. As you know OHP fresnels are actually two fresnels back to back. The DIYLABS has one fresnel with 13 inch focal length and the other is eight or nine inches. You could turn it around and it would probably work but you would have to move your light source out to 13 inches away from the fresnel. Because of the very steep projection angle of the nine inch focal length fresnel you should put the LCD between the two fresnels for best results.
To keep from seeing the rings in the fresnel it should be about an inch away from the LCD. That is the one fresnel between the projection lens and the LCD.
Hezz
you may have trouble finding a fresnel to use with this lens because of it's short focal length. I'm guessing 240mm to be about nine inches or so but you could probably use the diylabs fresnel combination. As you know OHP fresnels are actually two fresnels back to back. The DIYLABS has one fresnel with 13 inch focal length and the other is eight or nine inches. You could turn it around and it would probably work but you would have to move your light source out to 13 inches away from the fresnel. Because of the very steep projection angle of the nine inch focal length fresnel you should put the LCD between the two fresnels for best results.
To keep from seeing the rings in the fresnel it should be about an inch away from the LCD. That is the one fresnel between the projection lens and the LCD.
Hezz
Thanx for advice hezz thats actually exactly what i planned to do... but i plan to put the light source closer to it than that.... still tryin to figure out how the condenser lens helps out on the light source.... i also plan on using mirrors to make the unit smaller, and also another question for anybody.... if i use a mirror between my LCD and projection lens does it change the image (relect it or whatever... such as when your read whats on your T-shirt in the mirror and its backwards) and if that is the case can i just turn the LCD around and project light from front to back?
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