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#1 Filip Plesha

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Posted 01 February 2006 - 05:56 PM

Normally I'd ask such questions on some photo forum, but since tungsten lighting is not used as much in photography as it is in cinematography, I'm going to ask you guys here.


I have a problem with burning barn doors on my tungsten lights.
The thing is , when I try to close them to localize the beam by closing the doors they get so hot that I get steam comming out from vapourizing paint. On larger distances it takes an opening as small as 2 cm to get what I want, and this is where it gets really getting hot.
The effects are these:
it smells more like boiling watter than something burning, so I assume the paint is being "cooked" and the steam comes from that,
when it gets to that point, the paint gets soft and you can leave marks with your nails


So I was wondering, since you people are working with much more powerfull tungsten units (these are 1250W), what are your experiences with barn doors on this matter?

Are these that I have simply coated with lower quality paint, or is this something you have to live with?
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#2 Brian Drysdale

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Posted 01 February 2006 - 06:19 PM

I haven't had this effect for some time. It used to happen with the old broad type quarz lights, where the barndoors were extremely close to the lamp and the heat couldn't get out.

If you've painted the barndoors yourself, chances are the paint isn't heat resistant.

Try using flags to get the same effect, you'll also get a harder edge without getting the smoke effects from the paint.
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#3 Laurent Andrieux

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Posted 01 February 2006 - 06:24 PM

What exactly are your instruments ? 1250 W sounds to me like soft lights but thay have no barndoors... Are they Fresnel or open face lights ?

Anyway, the barndoors are made to resist the heat unless you close them to much... When they are brand new they might "cook and smell" a bit, but that shouldn't last. I'm afraid that a 2 cm opening is a bit small so that they get really close to the source...

The thing is that if you close them that much, may be is it because they are just too powerfull for your need...

I mean that closing the barndoor so close doesn't do much but lowering the intensity of the light.

May be you should better use flags a bit further from the source. Or a 300 or 500 W instrument instead. Or gel with Neutral density or lower it with a grid...
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#4 Filip Plesha

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Posted 01 February 2006 - 06:41 PM

No, I haven't painted them myself

The paint seems to be alright, it doesn't change color or anything, and when it cools down its back to normal (scratch resistant), but still it gets too soft when it gets hot, and the water seems to be vaporizing out.

I wonder why do they even paint those things if they can't get the paint right (the barn doors are original, from the same manufacturer, came with the lights)
















What exactly are your instruments ? 1250 W sounds to me like soft lights but thay have no barndoors... Are they Fresnel or open face lights ?

Anyway, the barndoors are made to resist the heat unless you close them to much... When they are brand new they might "cook and smell" a bit, but that shouldn't last. I'm afraid that a 2 cm opening is a bit small so that they get really close to the source...

The thing is that if you close them that much, may be is it because they are just too powerfull for your need...

I mean that closing the barndoor so close doesn't do much but lowering the intensity of the light.

May be you should better use flags a bit further from the source. Or a 300 or 500 W instrument instead. Or gel with Neutral density or lower it with a grid...



I close them only when I want to get a thin line of light, not to lower the light.

I wouldn't dream of trying to lower the output because I never get enough light from them anyway,
since I rarely shoot with fast film (usually up to 100ISO). I can rarely use the camera handheld, always have to use a tripod since I'm missing a stop or two for holding it in the hand.

The lights are Hedler photo/video tungsten compact halogen lights. Here is how they look like:
http://www.hedler.co.../c-leuchten.htm
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#5 Laurent Andrieux

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Posted 01 February 2006 - 06:45 PM

Tough I don't get a word of german, for personal political reasons, I assume these are 1000 W Fresnel...

The best to do is to use flags instead, a bit further from the source.

Consider Brian's post as the best one.
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#6 Filip Plesha

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Posted 01 February 2006 - 06:53 PM

I don't understand german either, I was just giving you the link to see the pictures.

And yea, C 10 are 1000W and C 12 are 1250W


I'll consider using flags, it will probably give a harder edge too (which is wha I'm after anyway)


But anyway, I was just asking to see if this smoke thing is normal or not.
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#7 Laurent Andrieux

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Posted 01 February 2006 - 06:56 PM

If it lasts and if it looks like the barndoor is sort of damaged I would say no...
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#8 Dimitrios Koukas

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Posted 01 February 2006 - 06:57 PM

Hello,
This lights, even that they do have barndoors, are not so sofisticated made to handle their own wattage.
Even in a 2k openface quartz lamp that is made for cinema or tv u can't have 2cm openning without burning the barndoor paint. Unless u are in a place that is windy and cold.
1250w in such a close distance for the barndoors is really too much.
If you have enough safe space u can do the same effect with a square (or something) hole in a cardboard paper, just be sure that u are not too close.(I would suggest 70-80cm away from the fixture and with the light set at flood position).Also u can do the same effect with cinefoil.
Dimitrios
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#9 Filip Plesha

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Posted 01 February 2006 - 07:01 PM

If it lasts and if it looks like the barndoor is sort of damaged I would say no...


Since I only turn them on when I'm adjusting, or exposing, they have pretty low working hours, probably less than 20 so far, so I guess they are pretty new. Maybe it will stop over time.
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#10 Laurent Andrieux

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Posted 01 February 2006 - 07:09 PM

no, 20 hours is good enuogh for them to stop that ! I mean if it last more than an hour or so...

Follow Dimitrios advice (though I like regular flags better than cut paper...)

(M8, Dimitrios, Iassou ! :) )
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#11 Michael LaVoie

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Posted 04 February 2006 - 08:49 AM

I don't know what kind of funds you are dealing with but if you regularly wish to make those small narrow beams and spots, I'd invest in a kit of Dedolights. They are designed specifically for that application.
www.dedolight.com
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