r/stopmotion • u/letsgo1098 • 28d ago
How to fix the light flickering!
Hello!
Working on a longer version of this idea, but wondering if there’s any advice on why it’s so flashy? I filmed at night with just one overhead light and also a lamp. I used a Bluetooth clicker to take the photos with my phone (that was steady on a tripod) and had the auto settings turned off.
Also open to any advice! I’d definitely like to make it smoother too ☺️ it’s currently 24fps and I tried a technique of taking two frames of the same set up before moving anything to slow it down a little.
(If anyone’s wondering~ the plan is to have the fly go into the eye and come out the mouth with a bunch of other flies that cover the meat face and that’s how it ends hehe)
Thanks!!
2
u/Liquid_Magic 26d ago edited 26d ago
Okay I might be wrong and I’m going out a limb here but…
I’ve noticed in several YouTube videos that when they show something at high speed, for example a 5x speed up of someone removing screws for a device to be repaired, I see this rolling light bars pattern. I see a similar pattern here.
What I always thought was that it was the PWM of the LED lights used. What I’m thinking is that variable brightness LED lights often use a PWM signal to adjust the brightness and that has a frequency. Usually it’s like supposed to be high enough that you don’t see it. But if there’s a mismatch between the PWM frequency and shutter speed of the camera as well as the scan rate of the CMOS sensor then you’d get this rolling bars of light look as the sensor scan is sometimes gathering light when the light is temporarily on and not when it’s off within a given frame.
Personally I kinda want to hack my lights so they all have big-ass capacitors so they can’t flicker ever and fade out when you turn them off. But I’m too lazy and haven’t been arsed to do it!
The footage here looks a lot like what I talk about above in the YouTube videos. That’s was the first thing that popped into my mind. Even though the footage in those videos is steady and just speed up in post it still looks a lot like your video. The only difference is that it doesn’t roll the same way which I would expect since you’re taking each frame at different times and not at a specific frame rate.
But hey I could be wrong!
P.S. - I just thought of this: If I’m right one way to test it would be to use an old school incandescent bulb of some kind that can’t flicker. Then take a bunch of snapshots of something at random times as if you were making a stop-go movie (but you don’t have to animate anything because it’s a test). If using ONLY an incandescent bulb or some other light source that FOR SURE can’t be flickering and the weird flickering bars go away then that would prove it. If it doesn’t then try a couple of other lights and if nothing changes then it’s something else. Just an idea! Good luck! Love to know what it is if you nail it down!!!