Film-Tech Forum ARCHIVE: Homemade Lamphouse

This is topic Homemade Lamphouse in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Cody Martin (Member # 2523) on 07-04-2004, 07:17 PM:

Hello everyone,
I was wondering if anyone has made their own lamphouse. I have seen a few 1000w GE light bulbs on the net and was wondering if anyone could make a fixture for one of these to work for film use. Anyone attempted this?

Thanks,
Cody

Posted by Dan Lyons (Member # 1454) on 07-04-2004, 08:01 PM:

Just save up your money for a real xenon lamphouse. Why waste time and money making up some half-assed wannabe lamphouse with the wrong colour temp? [puke]

danny

Posted by Steve Kraus (Member # 476) on 07-04-2004, 10:28 PM:

If you search you will find a thread about someone doing just that...got the bulb, socket, reflector, cooling fan, and box to put it in. As I recall it worked but almost as soon as it was done he got a real xenon lamp and that's what you should do, too. Note that any old light bulb won't do because unless the light source is concentrated into a very small area you won't be able to use a reflector to focus it onto the projector aperture. You'd be better off using some sort of bulb that already does all of this for you like a halogen slide projector bulb that is integral with a reflector. That might be a reasonable stopgap until you can afford a real lamphouse.

Posted by Brad Miller (Member # 2) on 07-05-2004, 12:18 AM:

Used lamphouses are becoming so cheap, take Danny's advice. If you're really hurting for cash and your screen isn't too big, look on Ebay for a Sun Gun. [Cool]

Posted by Phil Hill (Member # 371) on 07-05-2004, 12:45 AM:

I agree with smart-ass Danny and smart-ass Brad in their suggestions. There are plenty of reasonably-priced lamphouses showing up on eBay now and then.

A much better option!

>>> Phil

Posted by Paul Trimboli (Member # 1509) on 07-05-2004, 08:17 AM:

You can do like me, I have an arc lamphouse, I have taken all of the arc gear out aside from the mirror. I have yet to fit it but am getting a metal halide lamp which has a 7mm arc gap so is ideal for use with a carbon arc mirror since the ball of plasma created with carbons is about this big. The model lamp is a HMI 1200 W/S and the tech sheet on this can be downloaded from the Osram web site. You will need to get a sqaure wave ballast to run it other wise there would be flicker. [thumbsup]

Posted by Cody Martin (Member # 2523) on 07-05-2004, 04:32 PM:

Thank you all for your help. I have decided I'll just go with the slide show lamphouse until I can afford a real "light". Any suggestions on this? Do I need to get a slide projector with or without a lens?

Thanks,
Cody

Posted by Brad Miller (Member # 2) on 07-05-2004, 06:13 PM:

Can you give us some specifics of your setup so we can make some better recommendations? Screen size and throw, as well as projector make.

Posted by Gordon McLeod (Member # 33) on 07-05-2004, 06:24 PM:

The actual light source in a carbon arc is located in the crater of the positive carbon and is far less than 7mm in size. THe plasma flame between the two carbons doesn't contribute to the screen illumination
I can not understand the fascination a lot of people have with HMI light sources as they are more expensive per hour to operate, less light output per watt, longer arc gap so less optical precision is possible, and the colour temp changes over the lamps life not to mention a rather complex powersupply

Posted by Ron Yost (Member # 1850) on 07-05-2004, 07:03 PM:

There are two people I know who have self-built low-intensity 'lamphouses'. One is Jeff Stricker, a member here. Jeff, you out there? Do you still have your webpage showing your Brenkert rig?

The other is Sam Hunter. Pics of his self-built temporary light source can be found here on Film-Tech in the Pictures section. Look under "Screening Rooms", "SDH Cinema". (Sam eventually got an ORC1000, but has since sold it all).

I say, do what you have to do to get a picture on the screen (or the wall, or whatever). Small lamphouses are not that easy to find, in my experience. You may be perfectly happy with something you build yourself. There's no shame in it .. don't let folks drag you down and try to humiliate you. It's your system, it's your life, do what you can and want to with it. [Smile]

If you want something designed for the task and down the line a happy confluence occurs between you, it, and your $$, so much the better.

Ron Yost .. "Cinema October" home screening room, Brenkert BX80, RCA 9030 soundhead, ORC1000. "All Analog, All the Time". [Wink]

Posted by Jeff Stricker (Member # 224) on 07-05-2004, 07:36 PM:

Yes. I'm here...Well, my "screening room" is basically my shop and ham radio shack. Since my throw is just 15 feet, I figured I could get away with a quartz halogen projection lamp. I've been using an ENX lamp which is 360 W @82 volts. Don't let the odd voltage of some of these lamps scare you away --- you can use a variac to get any voltage you need. These lamps are plentiful on EBAY and can be had for as little as a couple of bucks a piece at times.

To make a long story short, there seems to be plenty of illumination. I'm using a 2 inch flat lens, so the picture is around 6 1/2 feet wide. Yes, the color tones are indeed "warmer" than the should be. But you get used to it, since you cant make an "A-B" comparison. The poo-poo'ers and nay-say'ers will have negative comments, but, heck, I'm just having a great time tinkering and running this old gear on a beer budget. [Wink]

I think if you search some of my other posts you can find the details of how I built these homebrew lamps houses (I've made 3 of them now for my three working machines).

I use a condenser lens salvaged from photo enlargers or old slide projectors...The distances (lamp - condenser lens and condenser lens - film plane) are found experimentally.

Having said all that, however, if I ever have a 'reel' screening room with a longer throw, I'll be wanting a small single phase xenon lamphose (anybody have one cheap, even if I have to fix the power supply?? I'd love to run some back yard movies!)

Cody, I'm up in Kokomo, if you would like to get together sometime.

Posted by Cody Martin (Member # 2523) on 07-05-2004, 08:41 PM:

Hello Everyone,

Once again thank you all for your help. I am just starting out in the projection world. I have worked at a theatre for a few months, so if my terminology is off, or if I am missing really basic thing, please excuse me.

I will be picking up my projectors Wednesday. They are 2 Motiograph AA from Derek Maxwell. I still have to make/buy a lamphouse, lens, and an upgrade in the sound system.

Once I recondition the machines, I am hoping to show some movies in my back yard, so screen size, throw, and almost anything have multiple variables. Our back yard is pitch black at night, so this is a positive for my situation. For right now lets say that my goal will be at least 15 feet throw, with 8 foot image(by the way, when everyone says there screen sizes, is this width or diagnal?).

I hope this is the kind of information everyone is looking for. If I have left anything out please let me know. I will be having a leg surgery in a few weeks, so this is going to be my keep busy project, aside from highschool.

Thanks for everyones help again.

Cody

P.S. If anyone has an old lens they would like to pass on to an aspiring projectionist I'm only a p.m. away :-). Or at least a suggestion on what to look for.

Posted by John Hawkinson (Member # 1135) on 07-05-2004, 08:42 PM:

Remember it's not the throw that matters, it's the projected image area...

--jhawk

Posted by Ron Yost (Member # 1850) on 07-05-2004, 10:36 PM:

Cody,

Real film uses real screen sizes, heighth and width. Diagonal measurement is used by the -video- home-theatre folks. No comprende the diagonal here. [Wink]

Schneider Optics has a wonderful auditorium lens-calculation program on their website. You might want to check that out .. it's free.

Ron Yost

Posted by Cody Martin (Member # 2523) on 07-05-2004, 11:07 PM:

Ron-

Thank you for explaining that. I appreciate everyone being so helpful to the newbie [Wink]

.
I'm going to check that program out tonight.

Thanks again,
Cody

Posted by John Pytlak (Member # 331) on 07-06-2004, 02:12 PM:

http://www.schneideroptics.com/software/theatre_design_pro/

quote:
Theatre Design ProTM (TDP) is a sophisticated software package useful to designers of Motion Picture Theatres and other facilities utilizing projection of various types. TDP calculates picture size, lens focal length and image shape due to keystone distortion and screen curvature.

http://www.iscooptic.de/Downloads_new/LensCal.exe

quote:
Lens Calculator Download

Posted by Cody Martin (Member # 2523) on 07-06-2004, 06:42 PM:

Hello,

Thanks for the links. I have been messing around with the theatre design program. Very nice piece of software for freeware. I also have downloaded, just haven't used the lens calculator.

I'm sorry I will have more questions, but for right now I'm looking for a lens and then the lightsource. I think while I rebuild the projectors I'll be able to find someone wanting to sell a lens.

Thanks,
Cody

Posted by Phil Hill (Member # 371) on 07-06-2004, 11:07 PM:

Cody... welcome to Film-Tech! Keep in mind NOT to pay any attention to what the likes of Joe Redifer, Brad Miller, Mark Gulbran...whatever, or those other wanna-be "professionals" have to say.

Only listen to me. I know all! [Wink]

Seriously, welcome!

>>> Phil

Posted by Philippe Laude (Member # 79) on 07-09-2004, 07:34 AM:

Hello Cody.
I built a small lamphouse for a friend of mines, starting from a SIMDA (Kodak) slide projector. It uses its genuine built-in 24V 250W halogen bulb, its complete mirror/condensers system, except for the last lens, replaced by the front lens of a f= 140mm cinema lens, and its complete power unit. To be able to place it a cabinet I had, I modified the cooling air flow, using a computer muffin fan.

It gives good results for a maximum 2.5m-3m wide screen. Of course, like you've already been told, it isn't xenon.

I have pictures if you want,I don't succeed in submitting pictures here. Just E-mail me.

Philippe