Gee, y' think ya might throw an alternate idea or two in there to balance out all that discouragement?

Show HD on a 72" screen maybe?

I don't really have any experience or advice to offer, but just to clarify your question: you are talking about night-time (after dark) projection, right?

Also, I'm thinking a more proper, reflective projection screen or material -- maybe even a cheap one -- might help offset any shortcomings from the projector. But again, I have no first hand experience.

I think musicvid10 is being a bit pessimistic. I just helped with a dance program where we projected a DVD video on a screen using an Epson consumer projector. The screen was about 12' by 8' (maybe a bit bigger, it was a school auditorium) and the picture was very good. Not theater quality by any means, but more than acceptable.

Best suggestion is to go to a retailer (Best Buy, etc) and get a demonstration. Now price wise, you may be a bit more than $300. We had to run the audio to a separate feed from the DVD player because the projector only had an internal speaker and no audio out, so that is something to be aware of.

Yes, having seen many school graduations, memorial services, and business presentations tanked because of overenlarged SD on underpowered projectors that couldn't even overcome ambient light, you could say I'm quite cautious. Whether I'm pessimistic or realistic in this case I guess will be the OP's call.

I would put my money on a big flatscreen teevee over a projector in any home entertainment application.

Hi s k r o o t a y p,

I think the quick math would be a little more than 13 feet.

At one time I had an Optoma EP771 projector, which was 3,000 lumens. The largest screen size I had it setup was at about 9 feet wide, on a roll-up white matt Optoma screen.

For your budget I think 20 foot wide would be a stretch. Maybe 10-12 feet and that size would serve a reasonable size family/neighborhood audience.

At 3,000 lumens the Optoma threw a reasonably viewable 9 foot wide picture, but almost everything I viewed at the time was 720 HD. To stretch SD to 20 feet will probably degrade the definition beyond being enjoyable, especially when many viewing may be used to 1080/720 HD TV's.

At any rate, per the manual it list 18 feet wide projection as the limit, and from viewing the 3,000 lumens at 9 feet wide, I think that would be a far stretch and would loose all brightness and contrast. You are also using a white tarp, which will absorb a lot of the light, which a projection screen usually reflects back to the viewer.

Before I purchased, I would check to rent a unit from a local A/V shop if available in your area. For a few bucks you could stretch out your tarp and try out a unit that fit within your budget, and get the results first hand.

Hope some of this may help.....


Best Regards.......George

I've got a used Epson projector i bought on eBay for $140. It does 2200 or 2700 lumens. I've got it set on 2200 to increase bulb life, using it in the living room on an 84" screen. Native resolution is 1024x720 but i use it mostly for playing DVDs. The picture is very acceptable even with one small room light on. I've tried it outside projecting on the side of a mostly white building at 2700, up to about 15 feet diagonal. The picture wasn't great, but it was still good enough to enjoy the movie, and i'm pretty sure that's all you're really after. I did have to wait for at least half an hour after sunset for the sky to be dark enough otherwise the picture was too washed out by ambient light.

Projecting onto a 20 ft. screen requires roughly 4-5 times the projector light output as a 10 ft. screen to realize the same perceived brightness.

TANSTAAFL

Thanks so much everyone! I certainly learned alot from this!!

FWIW, If you double the size of the image, then you need 2x2 times =4x more light for the same reflected brightness (since it's Four times the area ).
However, unless the projector is super-sharp ( along with the video going in ), there will be a greater chance the viewer will see the pixels.
IMHO it is better to reduce the picture-size, increasing the brightness and the sharpness will improve too.
A smaller screen is also easier to keep flat, should there be any hint of a breeze.
Now, what about the Audio?


Good Luck.

Why so big? I do a lot of conference room projector setups and I guarantee it's going to look like crap. It's going to be washed out, grainy and very dim. And that's on a proper of painted screen. Projecting it on a big white rag would be even worse.