You get the effect seen in this thread when all three of these conditions are true:
1) The prominent light source(s) flicker (changing brightness rapidly).
2) The exposure time is close to or faster than the frequency of the flicker.
3) The camera uses a "rolling shutter" which captures each image by gradually scanning across the image sensor from one side to the other.
You can get a similar effect with a "global shutter" camera, except in that case you won't see banding. Instead the video will just vary in brightness from frame to frame.
If you control the lighting then you can try finding light sources that don't flicker. Often the flicker is fast enough you can't see it with the naked eye, but you can usually detect it using a cell phone camera that is using a very fast exposure time. If your lights have a dimmer switch, try setting it to maximum or using a standard switch instead.
If you can't control the lighting, then your best bet is to increase the exposure time (longer shutter speed) until the flickering is no longer detectable.
Fun fact, many LCD monitors and TVs use a similar method to control backlight dimming. My left monitor has a fairly typical whole-screen flicker, whereas my right one modulates several different backlight zones in a pattern which gives the appearance of broken bands when captured with a rolling shutter. The size of the dark bands increases when the display brightness is reduced.
1) The prominent light source(s) flicker (changing brightness rapidly).
2) The exposure time is close to or faster than the frequency of the flicker.
3) The camera uses a "rolling shutter" which captures each image by gradually scanning across the image sensor from one side to the other.
You can get a similar effect with a "global shutter" camera, except in that case you won't see banding. Instead the video will just vary in brightness from frame to frame.
If you control the lighting then you can try finding light sources that don't flicker. Often the flicker is fast enough you can't see it with the naked eye, but you can usually detect it using a cell phone camera that is using a very fast exposure time. If your lights have a dimmer switch, try setting it to maximum or using a standard switch instead.
If you can't control the lighting, then your best bet is to increase the exposure time (longer shutter speed) until the flickering is no longer detectable.
Fun fact, many LCD monitors and TVs use a similar method to control backlight dimming. My left monitor has a fairly typical whole-screen flicker, whereas my right one modulates several different backlight zones in a pattern which gives the appearance of broken bands when captured with a rolling shutter. The size of the dark bands increases when the display brightness is reduced.
