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Florescent lights and flickering


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#1 Jacques Koudstaal

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Posted 08 September 2006 - 09:11 AM

Hi there

I am looking to build a small eye light unit that I will place on camera (Arri SR2). Due to budget constraint?s I am looking at using your regular mini house hold florescent tube and fitting rather then the more expensive kino. I am told by many people that you will get flickering problems. Is this so, and if so how noticeable will it be in a eye light on a facial CU for example?

If there is anyone who has tested this could you please let me know what your result where?

Thank you
Jacques
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#2 Frank Barrera

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Posted 09 September 2006 - 02:34 PM

There are two reasons why Kino style fixtures are so expensive: #1 The bulbs will maintain the correct color temperature. Normal flourescents are notoriously either magenta or green. It's hard to see this with the human eye but film and video pick it up easily. #2 the ballast provides flicker free light output. As well all cheap flos will flicker. The question is wheather or not the flicker will sync with your chosen frame rate or fall out of sync and show it's ugly self. I have shot with normal flos and film and have experienced no flicker, a little flicker and lots of flicker. Once I even wanted to see the flicker and there was none.

So don't do it for an eye light. You would be asking for random trouble. What you could do instead is buy a simple clamp lamp with a silver reflector. You can find this in a hardware store. Then put some heavy white diffusion like 216 on the face of it. Also put on a small hand dimmer (you can get that at the hardware store too). Adding some 1/4 or 1/2 CTB is a good idea becaue you would almost always be dimming the light very low which would effectively add too much orange to the light output. The bulb itself should be a photo flood bulb. But a standard 100 watt bulb will work fine. What you get is a nice round light wieght controllable eye light that will cost you about twenty US dollars.


good luck
F

BTW you should post these type questions in the Lighting forum
f
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#3 Stephen Press

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Posted 09 September 2006 - 04:07 PM

Making your own is till a good option. Flicker free ballasts are not that expensive. Instead of $40 for a standard one you can pay $80 for a flicker free. Also there are good color correct tubes out there you just need to experiment.
For a green screen heavy feature I shot I built all the fluros out of leftovers from a rubbish skip? I do this job for the glamour :rolleyes:
I upgraded the ballast and spent an afternoon testing the fluros for color. It gave me 6 good lights from about 20. I also got my brother who is an electrician to check my wiring. It was very cost effective.
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#4 Frank Barrera

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Posted 09 September 2006 - 09:53 PM

Here's a link to more technical info about this:

http://www.cinematog...escentLamps.htm

I still say that if all you want is a simple and inexpensive eye-light go with my earlier post.

F
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#5 Stephen Press

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Posted 10 September 2006 - 05:59 PM

Good link Frank.
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#6 Jacques Koudstaal

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Posted 11 September 2006 - 03:03 AM

Thank you guys, much appreciated.
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#7 Sean McHenry

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Posted 24 May 2007 - 01:08 AM

I know this is basically a dead thread but I wanted to mention that for small fills in a sort of horror piece I shot, I used a near daylight R20 25W in a really small clamp light meant for a reading lamp I picked up at the hardware store for about $5. The lamp was maybe another $4? Looked good on HDV and in the dark room competing with similar lamps in a 5 light house fixture over the kitchen table, it really helped kick the actress out of the limbo lit kitchen. You can see some pics here of that shoot:
http://natalielloyd.net/Track11.html

The table overhead lights were R20 tight spots so it fell off the table pretty hard. I put black wrap on the opposite sides of the overhead fixture to kill most of the spill from the translucent lamp shades and the limbo effect worked out fairly well for such a tight area. The Dinette area is only about 10' x 10'. You can watch the short here:
http://www.DeepBlueE...com/Track11.htm



Sean

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