I have a Nikon D750 and cannot figure out the logic behind video (or still photos in live view) and flickering. I live in Norway, so the electricity is 50 Hz. If I shoot video at 1/50 or 1/100 second I get no flickering when using indoors (1080p 24 fps). However, if my shutter speed is increased to 1/200, 1/400 and so on I get flickering again. Does anyone know why this is happening? I also tried to record video at 1/200 and play back (to ensure that it is "real" flickering and not just an issue with the live view preview) and the issue persists. I though any multiplier of 50 should provide a flicker free video, but this appears to just be the case for 1/50 and 1/100 second. Does it have anything to do with the readout time of the sensor/rolling shutter somehow?
Sadly this isn't how it works. It could work with 25FPS and 1/200 if the shutter is precisly on the light impulse.
Also keep in mind that even if the electricity is 50Hz, the light could have a refresh of 100Hz. Or you were just lucky that the shutter allways was on the light impulse.
Solution: Well, sadly you don't really have a direcr solution for this one. But youbhave two Options: 1. Buy yourself some Video Lights (Sometimes also normal lights have a label "Flicker free" those should work too) 2. Do not shoot with such high shutter speeds. If you know 180° rule and just do it for artistic reasons, skip this part:
You should allways record with dpuble the shutter of your FPS: 25FPS=>1/50 50FPS=>1/100 This will give you the most natural look. If you choose a higher Shutterspeed, the footage will kinda look robot-erisch and unnatural. If you choose a lower shutterspeed, it will have more motion blur and feel almost dreamy.
But you may want to use this for artistic reasons, a slow shutter for a dream sequence or a faster shutter for sport video where you wsnt to see everything and stop the video.
Lag. The time between shutter close and shutter open, when the cam is processing and saving the image, is real and adds up. Just guessing, but I'm pretty sure I'm right. If you can set exact shutter speeds, try just a bit higher than 1/200, like 1/205, and see what happens.