Shooting slow motion footage, especially very high speed shots like 240fps or 480fps, results in flicker if you don’t have high quality lights. Stadiums often have low quality industrial lighting, LEDs, or both. Resulting in flicker during slow motion shots even on nationally broadcast, high profile sporting events.
I was particularly struck by this watching the NCAA Basketball Tournament this weekend. Seemed like I was seeing flicker on half of the slow motion shots. You can see a few in this video (along with Flicker Free plugin de-flickered versions of the same footage):
The LED lights are most often the problem. They circle the arena and depending on how bright they are, for example if it’s turned solid white, they can cast enough light on the players to cause flicker when played back in slow motion. Even if they don’t cast light on the players they’re visible in the background flickering. Here’s a photo of the lights I’m talking about in Oracle arena (white band of light going around the stadium):
While Flicker Free won’t work for live production, it works great for de-flickering this type of flicker if you can render it in a video editing app, as you can see in the original example.
It’s a common problem even for pro sports or high profile sporting events (once you start looking for it, you see it a lot). So if you run into with your footage, check out the Flicker Free plugin for most video editing applications!
We released a new tutorial showing how to remove prop flicker, so if you have flicker problems on drone footage, check that out. (It’s also at the bottom of this post)
But what if you want to avoid prop flicker altogether? Here’s a few tips:
But first, let’s take a look at what it is. Here’s an example video:
1- Don’t shoot in such a way that the propellers are between the sun and the camera. The reason prop flicker happens is the props are casting shadows onto the lens. If the sun is above and in front of the lens, that’s where you’ll get the shadows and the flicker. (shooting sunrise or sunset is fine because the sun is below the props)
1b- Turning the camera just slightly from the angle generating the flicker will often get rid of the flicker. You can see this in the tutorial below on removing the flicker.
2- Keep the camera pointed down slightly. It’s more likely to catch the shadows if it’s pointing straight out from the drone at 90 degrees (parallel to the props). Tilt it down a bit, 10 or 20 degrees, and that helps a lot.
3- I’ve seen lens hoods for the cameras. Sounds like they help, but I haven’t personally tried one.
Unfortunately sometimes you have to shoot something in such a way that you can’t avoid the prop flicker. In which cases using a plugin like Flicker Free allows you to eliminate or reduce the flicker problem. You can see how to deflicker videos with prop flicker in the below tutorial.
Drones are all the rage at the moment, deservedly so as some of the images and footage being shot with them are amazing.
However, one problem that occurs is that if the drone is shooting with the camera at the right angle to the sun, shadows from the props cause flickering in the video footage. This can be a huge problem, making the video unusable. It turns out that our Flicker Free plugin is able to do a good job of removing or significantly reducing this problem. (of course, this forced us to go out and get one. Research, nothing but research!)
Here’s an example video showing exactly what prop flicker is and why it happens:
There are ways around getting the flicker in the first place: Don’t shoot into the sun, have the camera pointing down, etc. However, sometimes you’re not able to shoot with ideal conditions and you end up with flicker.
Our latest tutorial goes over how to solve the prop flicker issue with our Flicker Free plugin. The technique works in After Effects, Final Cut Pro, Avid, Resolve, etc. However the tutorial shows Flicker Free being used in Premiere Pro.
One common problem you see a lot is flickering from stadium lights when football or other sports are played back in slow motion. You’ll even see it during the NFL football playoffs. Stadium lights tend to be low quality lights and the brightness fluctuates. You can’t see it normally, but play video back at 240fps… and flicker is everywhere.
Aaron at Griffin Wing Video Productions ran into this problem shooting video of the high school football championship at the North Carolina State stadium. It was a night game and he got some great slomo shots shooting with the Sony FS700, but a ton of flicker from the stadium lights.
Let’s take a look at a couple of his examples and break down how our Flicker Free plugin fixed the problem for him.
First example is just a player turning his head as he gazes down on the field. There’s not a lot of fast movement so this is relatively easy. Here are the Flicker Free plugin parameters from within After Effects (although it works the same if you’re using Premiere, FCP, Avid, etc.)
Notice that ‘Detect Motion’ is turned off and the settings for Sensitivity and Time Radius. Well discuss those in a moment.
Here’s a second example of a wide receiver catching the football. Here there’s a lot more action (even in slow motion), so the plugin needs different settings to compensate for that motion. Here’s the before/after video footage:
Here are the Flicker Free plugin settings:
So, what’s going on? You’ll notice that Detect Motion is off. Detect Motion tries to eliminate the ghosting (see below for an example) that can happen when removing flicker from a bunch of frames. (FF analyzes multiple frames to find the correct luminance for each pixel. But ghosts or trails can appear if the pixel is moving) Unfortunately it also reduces the flicker removal capabilities. The video footage we have of the football team has some pretty serious flicker so we need Detect Motion off.
With Detect Motion off we need to worry about ghosting. This means we need to reduce the Time Radius to a relatively low value.
Time Radius tells Flicker Free how many frames to look at before and after the current frame. So if it’s set to 5, it’ll analyze 11 frames: the current frame, 5 before it, and 5 after it. The more frames you analyze, the greater the chance objects will have moved in other frames… resulting in ghosting.
With the player looking our the window, there’s not a lot of motion. Just the turning of his head. So we can get away with a Time Radius of 5 and a Sensitivity of 3. (More about Sensitivity in a moment)
The video with the receiver catching the ball has a LOT more motion. Each frame is very different from the next. So there’s a good chance of ghosting. Here we’ve set Time Radius to 3, so it’s analyzing a total of 7 frames, and set Sensitivity to 10. A Time Radius of 3 is about as low as you can realistically go. In this case it works and the flicker is gone. (As you can see in the above video)
Here’s an example of the WRONG settings and what ‘ghosting’ looks like:
Sensitivity is, more or less, how large of an area the Flicker Free plugin analyzes. Usually I start with a low value like 3 and increase it to find a value that works best. Frequently a setting of 3 works as lower values reduce the flicker more. However, low values can result in more ghosting, so if you have a lot of motion sometimes 5 or 10 works better. For the player turning his head, three was fine. For the receiver we needed to increase it to 10.
I think the most exciting thing about Flicker Free plugin is that people are willing to let us talk about it when they use it. Beauty Box Video gets used all the time on very high profile projects but no one wants to admit it publicly. It’s not worth some video editors job to say so-and-so pop star doesn’t have the flawless skin it looks like she has.
Flicker Free isn’t even officially released yet and we’re getting producers emailing us, letting us know it saved a shot (or shots) in their video AND they have no problem with us posting it. It’s awesome!
Such is the case with the music video from the Bloody Beetroots featuring Tommy Lee (of Motley Crue fame). One of the LED lights on the set was causing severe strobing in some shots. This isn’t regular flicker, it’s sort of rolling bands. It’s something we’ve seen only from LED lights and possibly electrical interference (the iPhone example in the FF demo reel is a good example of the problem). Flicker Free was the only thing that got rid of it. Just another big problem the plugin can solve. You can check out the final video below.
Wherein Jim Tierney rants and opines about After Effects, Premiere Pro, Final Cut Pro, and other nonsense