dark bands moving on the footage

F

frozenlights

Member
I shot some footage in mixed fluoreoscent and tungsten light and noticed dark bands moving on it from top to bottom like old time tv footage. I thought it is the fluoreoscent light causing it. But just now I noticed same thing is happening in yellow light too. I can see it on lcd screen of af100 too. I have'nt got the chance to see it in daylight. I will do it tomorrow. Any idea what is happening? I was shooting 1980p 25p and this is a pal country.
 
Could be phasing coming from slight shifts in the frequencies of the ballasts. Usually you can get this when shooting high speed and even slight fluctuations in the grid start showing as shadows seemingly creeping over the lit areas. What light sources you had in the picture? And what kind of "yellow light" was it? Can you post an example?
 
Yellow light sounds like sodium vapor lamps- those can pulse, strobe, etc too depending on the brand and the voltage. Sometimes you can mitigate this effect by experimenting with different shutter speeds. Sometimes it won't go away at all. Definitely worth it to bring a decent monitor and check shots as your shoot- especially in any situation where you're unsure about the lighting type.

-Noah
 
These were decoration lights of all sorts. fluorecents mostly. But now I am seeing this happening with all indoor lights including tungsten 100 watts bulb. It was not happening before. I have to check in the daylight. It is night time here. I will post some footage tomorrow. Thanks for the reply.
 
frozenlights said:
These were decoration lights of all sorts. fluorecents mostly. But now I am seeing this happening with all indoor lights including tungsten 100 watts bulb. It was not happening before. I have to check in the daylight. It is night time here. I will post some footage tomorrow. Thanks for the reply.
Click to expand...

Sounds as if you've shot in "flicker hell". Decoration lights often have cheap and rotten ballasts and the more light sources you have, the more this can add and give strange effects. And/or if the "grid" is powered by an old and not adjusted source like a generator. Happens on fairgrounds sometimes.

What I do not get is that you have it with tungsten light too. Is it really pure tungsten? Or have you other sources somewhere that may "pump" in the shadows? What exposure time/shutter degree you shoot? Which country?
 
You must log in or register to reply here.
Back
Top