linear scrolling? mag ballast vs electronic?

[Jason H]

Got some footage shot with 2 magnetic ballasts and a kinoflow and there seems to be a faint scrolling line across the entire frame when I scroll it in quick time. light then dark light then dark. When it plays in real time (24fps) you cant see it. What do you think is up?

 

[Dave Cox]

had this issue with magnetic ballasts. replaced the mag ballasts with electronic ones, set them to flicker-free and the problem dissappeared. The issue was with a 10K, but I believe it was simply that was the only head without an electronic ballast.

hope that helps!

 

[Ivan Cortazar]

I had similar problem with some street fluorescents. Is there any way to fix it? Any plug in, or hard way in Ae to fix it?

Thanks

 

[Nate Clapp]

not sure about after the fact fixes but using 1/60 shutter on the day fixes the problem, and in some cases 1/40 does as well- (144 degrees and 216 degrees in shutter angle film speak) 144 may be the the new 180 when dealing with non flicker free sources (including flos and sodium vapors) at least for RED. so now i consider using 144 and 24fps instead of 180 24fps if sources are unknown. has to do with 23.98 and rolling shutter i think.

 

[Jason H]

thanks guys! good info. I will be doing some testing of my own soon with these same lights and ballasts. nail it down...

 

[J. Bernard Vallon]

we had the same problem happen with some 1200 heads when we ran them with genni power. We were running on electronic ballasts, which was very strange. 144 degree solved it, we blamed the genni at first, because it wasnt crystal sync. but we noticed the same thing when we plugged into house power, which didnt make sense.

We were in Nowheretown, Delaware, and we wondered if the town's sine wave was less-than-perfect as well.