We Want to Use a Video Projector to Show Movies On Someone's House

[Carnac the Magnificent!]

My friend wants to buy a $2,000 video projector and project movies from his patio onto the side of his neighbor's (white) house. (She's OK with this.)

His patio is located about 30 feet from the side of her house. The idea is that we could show movies on this huge improvised screen, producing an image of about 20 feet across and by using the "keystone" image corrector to account for the upward angle.

Can a $2,000 video projector throw out the lumens needed to accomplish this feat, or are we tech-dumb dreamers?

P.S. How does the light output of a $2,000 video projector (DLP?) compare with that of a movie house projector?

[Stan Doubt]

My WAG is that this will not work very well. I have actually done this before, using bedsheets as a screen, but I did not put the projector so far away.

Beyond the brightness of the projector, you have to worry about ambient light. If this is a fairly well-lit neighborhood with street lights and such, you're not going to get a very good picture. If there is a way to safely put the projector closer, you'd probably get better results.

[Atticus Finch]

Woah, woah. Slow down there!

No matter what the other answers to this thread say about the feasibility of your friend's plan, don't let them buy the $2000 projector before you know what the image is going to be like.

Rent a projector for a while, try it out. Wait till you're sure, THEN they can sink $2000 into it.

[iamthewalrus(:3=]

I don't mean to be a thread-stealer Carnac, but I'm interested in the same kind of setup (except it would be inside my apartment).

I'm looking at a sub $2000 projector, but probably not for about four to eight months (depending on how effectively I can save money). I imagine that current offerings will have changed somewhat by then, but, in general, what should I look for? How many lumens is enough? What else is important?

Any good websites out there with a nice beginners guide?

[Tuckerfan]

I suggest that instead of buying one, your friend builds his own projector. That way he can stand a fairly good chance of getting it to work, if not, he's not out tons of cash. Here's (http://www.audiovisualizers.com/madlab/lcd_proj.htm) some (http://www.diyprojectorcompany.com/) sites with the necessary info. (http://archive.avsforum.com/avs-vb/showthread.php?s=&threadid=69517&highlight=OHP)

[Carnac the Magnificent!]

Woah, woah. Slow down there!

No matter what the other answers to this thread say about the feasibility of your friend's plan, don't let them buy the $2000 projector before you know what the image is going to be like.

Rent a projector for a while, try it out. Wait till you're sure, THEN they can sink $2000 into it.


Yes, we want to check the feasbility before he writes the check. We've seen some video projectors, priced at upward of $7,000, that put out light like a light tower.

As for ambient light, his community is rather dark at night. No nearby street lights, though the stars do shine bright.

[Bill H.]

As a general rule, to get the required lumens, take the square root of your screen size (diagonal in inches), and multiply it by 70. Add some more lumens if you're in a less than dark room.

[Bill H.]

Oh, a home projector doesn't compare to a theatre version. Theatre bulbs are arc lamps and are measured in watts, not lumens. A typical multiplex bulb is 3k to 4k watts. You'll have to do the math to figure lumens. I don't know the multiplier, but I know it's not a linear scale.

[Ludicrous]

For those interested in video projectors for home use, just remember that replacement lamps cost $300 to 500. That's 1000 to 2000 hours of viewing time per bulb.

[t-bonham@scc.net]

we could show movies I hope you are talking about your home movies. Because this is illegal if the "movies" are commercial films that you've bought a copy of.

Of course, a lot of people purchase or rent films, and invite friends over to see them. Without much worry about anyone reporting them. But you're planning on showing them outdoors, projected 20' wide across the side of a house. The chances of this being noticed and reported would be a bit higher!

[Mac Guffin]

I hope you are talking about your home movies. Because this is illegal if the "movies" are commercial films that you've bought a copy of.

Of course, a lot of people purchase or rent films, and invite friends over to see them. Without much worry about anyone reporting them. But you're planning on showing them outdoors, projected 20' wide across the side of a house. The chances of this being noticed and reported would be a bit higher!

I thought it was only illegal to show movies like this if you charged admission or made any money at all from the viewing. As long as they are not charging anything, how is this any different from showing the movies on a big screen tv in the back yard?

[Carnac the Magnificent!]

Can anyone provide a reasonable guesstimate to my opening post? I appreciate the legal concerns, but we do not intend on violating copyrights.

If this technology could work as described, I doubt my friend would balk at a $300 replacement light bulb.

[beltbuckle]

For those interested in video projectors for home use, just remember that replacement lamps cost $300 to 500. That's 1000 to 2000 hours of viewing time per bulb.

This is a good point, as I have a projector and was pretty shocked when it came time to replace the bulb. Projectors have internal timers in them, and many will plain shut down and tell you to buy a new bulb.


As far as the question goes, the answer is that yes it will work, but will it work well enough. To figure this out, I would rent several projectors with different light output. You will likely need a pretty powerful consumer model to do the job. Just rent 2 or 3 units of different output, compare, then make a buying decision. Remember that the further away the projector is from the target, the more power you will need. Same is true if the "screen" absorbs a lot of light (matte paint finishes would absorb/diffuse light more than semi-gloss).

[CookingWithGas]

Oh, a home projector doesn't compare to a theatre version. Theatre bulbs are arc lamps and are measured in watts, not lumens. A typical multiplex bulb is 3k to 4k watts. You'll have to do the math to figure lumens. I don't know the multiplier, but I know it's not a linear scale.
Apples and oranges. Watts measure power consumption, lumens measure light output. Relationship depends on the efficiency of the technology. For example, a 20 watt fluorescent tube might be able to put out as many lumens as a 150-watt tungsten-filament incandescent bulb.

[aileron]

I've used a few projectors, but only indoors.

First of all, I think a throw distance of 30ft would be unrealistic for any consumer projector, the ones I've had focus out only to a 250" diagonal at roughly 350" from the screen.

Second, I doubt any $2kUSD projector will provide enough of the good stuff to reach out 30ft and give you acceptable photons.

And finally, unless the house in question is some sort of seamless concrete, the outline of bricks or siding panels will be quite horrendously annoying.

I'd say indoors is your only option for a commercial projector under $2k, but I've had fine outdoor results on moonless nights with a washing line, a white king size topsheet, and some beach chairs.

Your distance, surface, and size aren't looking realistic though.

<a href="http://www.nectechmedia.com/throw/throw.htm">Here's</a> <a href="http://www.sanyo.com/calc/index.cfm?FUSEACTION=home%2ECalcForm">some</a> <a href="http://htrgroup.com/?tab=projector-docs&section=minmax-throwdistance">calculators</a> to work out your sizes.

[graz]

I have done exactly what you're describing using a projector that my brother owns onto our neighbours white house. The projector cost £3000 so although I don't know the model I'm assuming it's similar to the one your friend is interested in buying in terms of specifications.
We were able to clearly make out the picture, at night, from a projected distance of about 40 ft and the image was approx 15-20 feet wide, bearing in mind there was some ambient street lighting about twenty feet away from the 'screen' the picture quality was reasonable. (I've seen worse picture quality on tvs using indoor aerials).
If the surface of the house is flat and painted white you shouldn't have a problem.
I have to emphasise that although watchable, the picture isn't great so realistically its fine for a bit of fun but not for serious viewing I'd say.

[Ike Witt]

You may want to check out this place (http://www.projectorcentral.com/home-theater-multimedia-projectors.htm) but keep in mind these are for home (interior) use.

[gotpasswords]

Have a look at "corporate" or conference-room projectors - they're intended for use in rooms with the lights on, so they put out a rather bright image.

I borrowed one from work last year and had entirely satisfactory results at a roughly 30 foot throw onto a king-size bedsheet. This was an older unit that maxed out at SVGA, but it was entirely adequate for entertaining a campground.

[Chronos]

As a general rule, to get the required lumens, take the square root of your screen size (diagonal in inches), and multiply it by 70. Add some more lumens if you're in a less than dark room.Shouldn't the lumens required scale as the square of the linear screen size, not the square root?

And how well this will work will depend greatly on the ambient light levels. If you're out in the absolute middle of nowhere on a moonless night, then almost any projector at all would be adequate, but if you've got houses, then you're not middle-of-nowhere. An eyeball gauge of "Yeah, it's pretty dark around here" isn't nearly precise enough to say. The simplest method would just be the empirical one suggested by beltbuckle and others: Try a few out, and see what (if anything) looks acceptable and what doesn't.

[Carnac the Magnificent!]

Great answers, folks.

I think theatre-quality image isn't important. To my way of thinking, it's the event itself that makes it so fun, not the actual image.

I stopped in Baltimore's Little Italy a couple years ago and stumbled across an outdoor film festival. They used a movie projector to throw a truck-sized image about 70 feet.

Not killer quality, but quite decent.

BTW, I have no idea why high-end ($5,000) video projectors cost so much. The optics wouldn't seem to compare with an amateur telescope. Any ideas?

[Tuckerfan]

Great answers, folks.

I think theatre-quality image isn't important. To my way of thinking, it's the event itself that makes it so fun, not the actual image.

I stopped in Baltimore's Little Italy a couple years ago and stumbled across an outdoor film festival. They used a movie projector to throw a truck-sized image about 70 feet.

Not killer quality, but quite decent.

BTW, I have no idea why high-end ($5,000) video projectors cost so much. The optics wouldn't seem to compare with an amateur telescope. Any ideas?LCD projectors (see the links in my previous post) use a combination of three monochromatic LCD screens, combine that with the bulb which costs $100+, and it's pretty easy to see why.

[Mangetout]

You probably want to make sure you have the neighbour's permission, too.

I'd suggest renting a projector of similar spec to the best you can afford. Some models can't zoom narrowly enough to project a great distance without it broadening into a huge, pale image.

[Ryle Dup]

You probably want to make sure you have the neighbour's permission, too.

My friend wants to buy a $2,000 video projector and project movies from his patio onto the side of his neighbor's (white) house. (She's OK with this.)

You should really just rent a projecter, see how it works, maybe rent a couple if the first one doesn't work very well, and then after you've tested them out, think about buying.

[Mangetout]

Oops, not sure how I missed that comment; I did go back and look for it several times. Ah well. I still say rent one first.

[KP]

Definitely rent! Usually, office rental places will credit the rental towards a purchase.

I've had a used LCD "presentation projector" for years. It was pretty darn fancy in 2000 and though it's hardly a powerhouse or feature-filled by today's standards, it works, indoor or outdoor, just fine. Mine has composite, S-video and RGB inputs, so you'll have no difficulty finding one that interfaces with video gear

I concede that you're going to have significant degradation at 20+ ft, but you know what? It really doesn't matter! As a kid, I gratefully watched much worse, on TV, in run-down drive-ins, cartoons projected each night on a brick wall abutting an outdoor cafe in Ottowa, etc. The whole sense of event makes up for everything

However, I think the logistics of the audio will be tougher than vieo quality issues: you don't want to wake the neighborhood (hey, invite them over!0 and sound dissipates quickly outdorrs. With video, you can always adjust distance and size to get a compromise you can live with. With audio, if it ain't there, it ain't there, and you'll be stuck huddling near the speakers -- why bother?

Though I recently bought a bulb for it on eBay ($150 vs $400 retail) "just in case, I consider it an incredible bargain compared to my friends who bought rear projection CRTs (and paid $100 each year for to have it retuned until the CRTs got burned in and they had to buy a new one) or plasmas and other screens. They spent much more than I did (admittedly I got an incredible deal) and got a fraction of the screen area.

To me -and it's a personal call- the difference in contrast indoors is minimal, and other minor disadvantages have been barely worth mentioning. The eye adapts -- or even the best broadcast TV 15-20 years ago would have driven us mad and blind. To my father, who has medical conditions that impact his vision and ability to comfortably position his body, it's been more than a godsend.

Give it a try and see for yourself. Maybe I'm an idiot, but I've heard/read so many naysayers on so many forums, yet I've personally had nothing but enjoyment.

[brachyrhynchos]

For the past 5 years, I've run the AV for the annual meeting of mosquito people here in NJ. We've used a variety of laptop projectors, generally within the 1200 lumen range to project onto a 12 or 15x15 ft screen in a large ballroom. The picture shows up best, of course, if the room is darkened, but it is quite acceptable under dim lighting as well. The last on we've used was the Infocus LP250 ((1300 lumens). The bulb replacement costs are horrendous, but the projectors are also used for lectures and seminars, and we've rarely had to replace the bulb.

I can't see why it wouldn't work, but I also go along with the suggestion of renting one to see the results. One thing that I've noticed is that the color output varies considerably among models (but this may be something to do with the interplay of Powerpoint presentations and drivers - video tape seems to be more consistent).