I don't know how it works that thing that film fps is 24 vs 25fps for EU and 30 for USA...
From what I know here in EU we have 50hz in hour home so all lightbulbs for example are flickering at that frequency, in USA it's 60Hz so the difference in video fps is justify by that. if we record a scene at 60fps lit by a lightbulb powered by a 50Hz current we will record also the fliker since light will be of different intensity each frame, with 25 fps we will record in sync with the current of the lightbulb so frame will get all the same light.
My question is if we record at 24fps in EU will have little off sync, maybe (I don't know) it's not visible, but in USA it will be a problem, or not? So how can a videomaker work with 24fps in 60Hz country? Does he need some particular transformer that changes the current freq for the light used? Or there are light that flickers at 24fps and support both 50 and 60Hz current?
Just curious
Although I don't work as a video professional, I don't know of any special lighting to match 24fps footage. It would still be running off of 60hz.
I think the main issue is the shift in the color spectrum of a constant light source throughout the AC cycle if that is what you mean by flicker. As long as your shutter is longer than the AC period (i.e. 1/60s @60hz) the shift is minimized since you captured the full spectrum. The effect is much worse if you are using shutter speeds less than 1/60s. Then you are just capturing a portion of the full spectrum and shifts will be very obvious. I really first noticed this not with video but with stills shot under fluorescents.
Quote from: Francis on February 13, 2013, 04:57:14 PM
Although I don't work as a video professional, I don't know of any special lighting to match 24fps footage. It would still be running off of 60hz.
I think the main issue is the shift in the color spectrum of a constant light source throughout the AC cycle if that is what you mean by flicker. As long as your shutter is longer than the AC period (i.e. 1/60s @60hz) the shift is minimized since you captured the full spectrum. The effect is much worse if you are using shutter speeds less than 1/60s. Then you are just capturing a portion of the full spectrum and shifts will be very obvious. I really first noticed this not with video but with stills shot under fluorescents.
Yeah you are right with photo you get rid of the problem changing shutter speed, so why shouldn't it be the same for video, maybe another coffe would help me getting up :D
thank you Francis, and have a good pics :)
I'm not sure what you can do with video. Keep the light sources out of the scene. You could still use a shutter of 1/60s @24fps if it was a big issue. Sometimes they use the flickering of fluorescents to change the mood, like in horror or thriller genres.
Classical light bulbs don't flicker in a way that is disturbing. The glow filament emits photons because it's electrically heated. It glows flickerless like a heated horse shoe. It doesn't cool down that fast to observe flickering with human eyes or a camera at 60 fps. Think of switching a light bulb on and off, it's kind of inert.
With neon tube, energy saving bulb are basically the same its different and they flicker. It's better to use a higher rate than 60 Hz for the light source.
See link for example. I have no interest in selling this stuff.
http://www.kinoflo.com/FYI/FAQs.htm