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Movies Forum Index » Cinematography (Super8) Forum » Questions regarding replacing lamp in a projector with a halogen lamp
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| HiC |
 Posted: Wed Oct 11, 2006 3:22 pm |
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If replacing the lamp in a projector with a small, low wattage halogen lamp
to project through a condenser lens, what I wonder about are the properties
of the light going through. It's my understanding that projector lamps are
made to a particular color spectrum - is this correct?
Will any small halogen lamp of the desired voltage/wattage work? Or is there
more than one "kind" - as far as the kind of light they emit? What about the
opal diffuser that goes in front of the halogen bulb, is there more than one
kind or color, or more specifically a particular type I should look for?
Thanks for all input. |
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| Steve Dix |
| Posted: Wed Oct 11, 2006 3:50 pm |
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On Wed, 11 Oct 2006 20:22:23 GMT, "HiC" <brassplyer@xahoo.xom> wrote:
Quote: If replacing the lamp in a projector with a small, low wattage halogen lamp
to project through a condenser lens, what I wonder about are the properties
of the light going through. It's my understanding that projector lamps are
made to a particular color spectrum - is this correct?
Will any small halogen lamp of the desired voltage/wattage work? Or is there
more than one "kind" - as far as the kind of light they emit? What about the
opal diffuser that goes in front of the halogen bulb, is there more than one
kind or color, or more specifically a particular type I should look for?
Thanks for all input.
It might help if you go to http://www.filmshooting.com/ and direct
your questions there. There's also a lot of information on other
people's homebuilt digitisers.
--
http://www.cdbaby.com/sinistrals http://sinistrals.stevedix.de/
http://www.mp3tunes.com/TheSinistrals http://www.stevedix.de/blog
http://www.snorty.net/ <steve@stevedix.de> |
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| Louis Boyd |
| Posted: Wed Oct 11, 2006 4:22 pm |
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HiC wrote:
Quote: If replacing the lamp in a projector with a small, low wattage halogen lamp
to project through a condenser lens, what I wonder about are the properties
of the light going through. It's my understanding that projector lamps are
made to a particular color spectrum - is this correct?
Will any small halogen lamp of the desired voltage/wattage work? Or is there
more than one "kind" - as far as the kind of light they emit? What about the
opal diffuser that goes in front of the halogen bulb, is there more than one
kind or color, or more specifically a particular type I should look for?
Thanks for all input.
Mostly you should look for the same make and part number as the old bulb
or assembly, or at least one specified as an exact replacement by it's
manufacturer. Mechanical fit including position and shape of the
filament, reflector shape if any, and wattage are the most important
consideration. Halogen lamps work over a relatively narrow filament
temperature range. They don't have a great range of color temperature
without exterior filtering. Using one of higher wattage is likely to
tax your projectors cooling, and perhaps damage the case or optics. A
lower wattage one just won't be as bright and probably won't last any
longer as the designed unit. You might have the choice of a 115 or 220
volt bulb but it would only make sense to change if you were moving to a
country with different supply standards.
I would expect the existing diffuser should be reused. If you want
special color filtering that can easily be added in front of the
projection lens. No point putting it near the bulb where it has to
withstand higher temperatures. Most "tint" filters absorb the unwanted
energy, converting it to heat. Dichroic filters reflect unwanted
energy, but it has to go somewhere. |
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| Sorcerer |
| Posted: Wed Oct 11, 2006 5:35 pm |
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"HiC" <brassplyer@xahoo.xom> wrote in message
news:3ocXg.5880$Lv3.673@newsread1.news.pas.earthlink.net...
| If replacing the lamp in a projector with a small, low wattage halogen
lamp
| to project through a condenser lens, what I wonder about are the
properties
| of the light going through. It's my understanding that projector lamps are
| made to a particular color spectrum - is this correct?
No. You are more likely to have colour error in the film, especially
if black and white.
| Will any small halogen lamp of the desired voltage/wattage work?
Yes.
| Or is there
| more than one "kind" - as far as the kind of light they emit?
There are many types of light sources. You can even use sunlight
directed by mirrors into lenses if you want to go to the trouble.
Clouds may be a problem.
| What about the
| opal diffuser that goes in front of the halogen bulb, is there more than
one
| kind or color, or more specifically a particular type I should look for?
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| Thanks for all input.
Try it by taking it out. You'll soon see the effect.
Androcles |
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| HiC |
| Posted: Wed Oct 11, 2006 6:24 pm |
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"Louis Boyd" <boyd@apt0.sao.arizona.edu> wrote in message
news:egjnat$ptf$1@onion.ccit.arizona.edu...
Quote: Mostly you should look for the same make and part number as the old bulb
or assembly, or at least one specified as an exact replacement by it's
manufacturer.
I'm anticipating experimenting with creating an aerial image (i.e. not
projected onto a screen but rather directly into the capturing camera
optics) with a condenser lens and therefore need a lower wattage light
source since as I gather a regular projector lamp is too bright. |
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| HiC |
| Posted: Wed Oct 11, 2006 6:25 pm |
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"Sorcerer" <Headmaster@hogwarts.physics_b> wrote in message
news:_keXg.125655$wg.39463@fe1.news.blueyonder.co.uk...
Quote: | What about the
| opal diffuser that goes in front of the halogen bulb, is there more than
one
| kind or color, or more specifically a particular type I should look for?
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| Thanks for all input.
Try it by taking it out. You'll soon see the effect.
Androcles
What "it" are you referring to? |
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| Bob May |
| Posted: Wed Oct 11, 2006 6:42 pm |
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The opal screen, of course!
--
Yeppie, Bush is such an idiot that He usually outwits
everybody else. How dumb! |
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| HiC |
| Posted: Wed Oct 11, 2006 6:49 pm |
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"Bob May" <bobmay@nethere.com> wrote in message
news:yaSdnTAzG9jdHLDYnZ2dnUVZ_o6dnZ2d@nethere.com...
Quote: The opal screen, of course!
Okay, well what I was getting at originally was is there more than one
kind/color opal diffuser? Ultimately, which kind of opal diffuser should I
combine with which kind of halogen bulb for best results capturing film? |
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| Sorcerer |
| Posted: Wed Oct 11, 2006 8:16 pm |
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"HiC" <brassplyer@xahoo.xom> wrote in message
news:O3fXg.8028$Y24.4022@newsread4.news.pas.earthlink.net...
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| "Sorcerer" <Headmaster@hogwarts.physics_b> wrote in message
| news:_keXg.125655$wg.39463@fe1.news.blueyonder.co.uk...
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| > | What about the
| > | opal diffuser that goes in front of the halogen bulb, is there more
than
| > one
| > | kind or color, or more specifically a particular type I should look
for?
| > |
| > | Thanks for all input.
| >
| > Try it by taking it out. You'll soon see the effect.
| > Androcles
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| What "it" are you referring to?
<yawn>
Androcles |
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| per.corell@privat.dk |
| Posted: Thu Oct 12, 2006 4:22 am |
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HiC wrote:
Quote: Thanks for all input.
Now I have the same problem , these old p28 bulbs are expensive and
with a life of some 20 hours -- streched using 110 volt and a 220 -110V
transformer so they run at max 100 volt -- I also had to experiment.
http://arch.designcommunity.com/topic-10104.html
But what I realy want , is to maximise esp. one projector -- an
Epidiaskop -- from 1000 watt 110 V. possible up near 2500 w 220 V. ---
this projector ;
http://home20.inet.tele.dk/h-3d/Epidiaskop-sm.jpg
Now what I found with that projector is, that the Episkop part of it
work well with two 500 watt 220 V. Halogen lamps, just cheap ones from
a work light but, the Diaskop part, the smaller lens, simply work bad
with these two lamps .
Like HiC I am looking for any relevant advise --- best advise that make
it possible to expand the light source. |
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| Bob May |
| Posted: Thu Oct 12, 2006 11:01 pm |
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When you get it all done, you'll probably find that it would have been
better to have just gotten the larger projector!
--
Yeppie, Bush is such an idiot that He usually outwits
everybody else. How dumb! |
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| Bob May |
| Posted: Thu Oct 12, 2006 11:03 pm |
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Ype, there's all different kinds of diffusers. Different thicknesses,
differnt color balances, different densities of the diffuser material and
different sizes of the plates. You can use thinner glass with a higher
density or a thicker glass with less density and come up with basically the
same thing.
Now, go hit the data books and figure out what you want.
--
Yeppie, Bush is such an idiot that He usually outwits
everybody else. How dumb! |
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| per.corell@privat.dk |
| Posted: Fri Oct 13, 2006 7:03 am |
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Bob May wrote:
Quote: When you get it all done, you'll probably find that it would have been
better to have just gotten the larger projector!
The largest Episkop's was based on 1000 mm lenses , they was some 500
Kg. and carried up to 6 lamps --- I wonder if it is even possible to
buy optics with this quality ,if such was made and sold for less than
the cost of a farm ; realy I would find it very strange if you could
find an Episkop today with an 800 mm. Leitz quality lens so no, just
"finding" a bigger one is no alternative. |
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