newb needs expert advise.

[dragonheart]

I have a 7" lcd and was looking to convert it to projection. I have read many websites on diy projections and even more confused than before.

My tv room is 176" x 128" and would like to make full use of the 120" wall. (I know wishfull thinking). my 3 biggest question are:

1: what is the biggest image I can get from a 7" lcd without losing image quilty?
2: what is size lens, focal length and box is recommended?
3: how does this effect hdtv? (more just curiosity)

I'm not looking for sime huge box in the of my room (like i"ve seen in videos). just somthing small I can place on a shelf above the couch.

I'm asking for as many opinoins as possible, so everyone feel free to pitch in your wisdom.

thanks

ps remember I am easily confuse so try be simple.

 

[zaner21]

1: what is the biggest image I can get from a 7" lcd without losing image quilty?

What is the resolution of your 7” LCD? 320x240, 640x480, 800x600

Image quality is in the eye of the beholder. Meaning what looks good to me might not look good to you or what looks good to you might not look good to me.

I can see the pixels of a 108” diagonal image from 12 feet away using a 640x480 resolution EIKI projector.

2: what is size lens, focal length and box is recommended?

Using Lumenlabs calculator… http://www.lumenlab.com/focal_calc.php

To get an image the size of your wall, 120”, with a throw distance of 160” you would need a 224mm projection lens. If your going to use a split fresnel design then you would want to try and match the front fresnel to the projection lens focal length. I think there is a standard size fresnel lens that has a 240mm or 230mm focal length. Another option is to use the projection lens from a CRT projector that is big enough to cover the entire 7” LCD. Then you wouldn’t need a front fresnel; just the back one, closest to the lamp.

3: how does this effect hdtv? (more just curiosity)

I don’t understand what your asking for question number 3?



I hope that helps at least a little bit.

Zaner21:

 

[dragonheart]

thanks for your response. I found it quit helpful.
to answer you questions. the tv is 234 x 480 res

http://www.bestbuy.com/site/olspage...CategoryId=pcmcat95100050020&id=1171058029518

that's a link to bestbuy website that can give more detail on the tv.

and the tv is supposed to have and buit in hd tuner. but if I convert it to a projection amy I gonna lose the hd image is what I was wandering.

what I am looking for most is to upgrade from my 20" crt tv to lcd but found a diy projector to be more in my budget.

 

[zaner21]

From that website…

Built-in ATSC and NTSC tuners for access to both digital and analog over-the-air programming. Note: Digital content, regardless of broadcast resolution, will be displayed at standard-definition (480i) screen resolution.

So no, you can’t get high def quality from that LCD. You need at least 720 horizontal lines of resolution to be “HD”.

Zaner21