You thought you did everything right. You composed your frame beautifully. You moved your camera remarkably. You captured your shot at a high frame rate so you could slow it all down in post to make it look all cinematic and gorgeous, but—some incandescent or fluorescent lights decided to crash the party and cause some ugly flickering. What do you do? You could scrap it, replace the bulbs, and do a tedious and expensive reshoot or you can try out the super fast, super easy post-production method demonstrated in this tutorial by Blue Mantle Films. And you won't need any plugins to do it!

The technique used in the video is awesome for those who may have miscalculated their camera settings, didn't realize there was an incandescent or fluorescent bulb on set, or just simply didn't know flicker even existed. However, this method does leave you with an image that isn't perfectly sharp, so the best thing to do, if you can, is to take certain precautions to avoid flicker altogether.

If you've ever encountered flickering, or "banding," in your videos and wondered why it's happening, the reason deals with the interaction between light sources and camera settings. You see, though the light emanating from certain lighting units may appear to be continuous, many bulbs are actually giving off pulses of light. When your camera's shutter speed and frame rate don't line up perfectly with the frequency of these pulses, you've got some nasty flickering on your hands.

Typically this is more of a high-speed video issue, but it does occasionally happen when shooting at 24 fps or 30 fps and there are a few ways to avoid it. If a light source is the culprit, you can change the bulb or go with a natural, continuous light source, but if it's a TV, computer, or another type of screen that's causing you trouble, you can also usually slow down your shutter speed a touch to eliminate it. So, if you're shooting at 24 fps with a shutter speed of 1/50, you can go down to 1/40 (or whatever's closest) and completely remove that strobe effect.

However, if that doesn't work or if you're shooting high-speed video, you'll have to carefully calculate your camera settings in relation to your light source's pulse frequency. RED actually has a great tool called Flicker Free Video (available on its website or on the free RED Tools app) which makes the calculations for you. 

Source: Blue Mantle Films