Short flurouscent lightning test

X

Xax

Active member
i read a lot about problems with cheap balasts and flickering, green touch etc. etc.

today i went to the local home depot-ish shop and bought a T8 daylight fluro (with balast and casing) + a 150w worklight, i paid 13 bucks for both. (10 euro)

i tested with the following "dialogue" (don't pay attention to what is being said, it means nothing :)) - no flickering, no green stain (i color corrected it a bit for a bit of tan for both of them though :laugh: )

did i missunderstand something or am i just lucky to be able to buy a flicker-free balast+daylight fluro for 5 bucks since it's running on 50hz and i'm recording in 25p?

thanks for any information or feedback you can give me

here's the clip (really bad angle and cut, but well i just wanted to test the light :laugh: )

http://members.inode.at/xiaosu.han/fluro.mov (3,07mb)

ps: the background of the first guy is lit with that 150w 8 dollar worklight i got.
 
the tan was probably because you were using a home depot bulb and those have lower color temps than 3200K or 3000K.

It's not that you were lucky with the 50Hz balast and the 25fpt PAL camera, that's basic electronics. In 50 Hz countries if you are shooting 25 fps you are fine since the balast flickers at 50hz and 50/25=2 so it's even. If you are shooting with high shutter speeds like 2000/1 of a second you could still have a problem. If I were to come over there and shoot on my NTSC camera (30 fps) than we could have a problem or if you were shooting film at 24fps than you could have a problem since 30 and 24 don't go evenly into 50. If you have any problems you can also change shutter speeds to something divisable by 50.


Here in the US power is at 60Hz and with NTSC 30FPS we can do the same thing with magnetic ballasts. But for 24 FPS film or 24P video we can have problems. On one project we shot 24p under cheap store flos and just put the shutter on 1/60 of a second, rather than the usual 1/48 of a second we had been using cheaper for the other scenes.

The green spike is a problem with low CRI. Every flo tube has a Color Rendition Index printed on it. For film and video you want CRI 90 or better. Cheap tubes have CRI of like 60 or 70 and that green spike. A CRI of 85 might be ok but that could be pushing it. Also the green can be taken out in post but it can be a pain. If you do end up with a a tube with a bit of a green spike they also make a "minus green" gel that's kind of a pinkish color and can take the green out of the light if you wrap it around, or put it infront of the tube.

I'd also like to know, how did you mount the flo fixture?
 
anamorphic?

anamorphic?

Looks good, did you use an anamorphic adaptor on this shoot? Or is it just on letterbox mode? Thanks, Franch
 
we are going to mount the fixtures onto wooden boards i think, and build some handle for handheld shots and possibilities for mounting it on a tripod, lightstand, too.

in this shot, the protagonists were sitting and the flo was ont he ground between them

i didnt use an anamorphic adaptor, i just used squeeze, don't mind the resolution loss that much,.. 900 dollars is a bit over my budget :)

thanks for the infos!
 
Fitz, Wouldn't all lights be affected equaly by the 60Hz power cycle, meaning even halogen-tungsten based? When shooting 24p I mean. Just curious.
 
I didn't read your post carefuly enough. if you had a T8 daylight than you would have had no flickering at any speed. Since you were talking about cheap home depot lights I was thinking T12 magnetic.

Halogen-tungsten lights are continuasly burning and not effected by the power cycle. Flos (and HMIs for that matter) need to have a ballast that regulates the flow of electricity to them. Magnetic ballasts work at the frequence of the power cycle. High frequency electric ballasts (like those found in T8s & T5s) cycle at thousands of times per second so at any camera speed the flicker is so small that it won't register.
 
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