Things to Consider When Shooting Slow Motion Action

Video Producer Chase Kubasiak shares how to achieve exciting and impactful video through the use of slow motion scenes. In this humorous B&H tutorial, Kubasiak highlights three key variables to consider when setting up your slow motion shots.

First is frame rate. Capturing video at higher fps (frame per second) than the cinema standard of 24 fps allows you to slow down the action. If you were to shoot your scene at 120 fps and then play the footage back at 24 fps you would be seeing the action five times slower than the actual speed. To determining what frame rate is best for you, you should look at the speed necessary for the action to display properly and the duration you want the action to last in playback.

The next thing to consider is shutter speed. This determines the amount of motion blur your subject is going to have. The longer the shutter stays open the more blur you'll end up with. The general rule of thumb, when it comes to creating natural looking motion blur, is to set the shutter speed at twice that of your frame rate. But you should play with shutter speeds to determine whether more or less motion blur is best for your vision.

Lastly, you need to consider lighting. Because faster frame rates and shorter shutter duration reduces the amount of light your sensor will actually be exposed to, you will need to make sure you have enough light to get the shot. You may also notice how slow motion footage can pick up on the flickering of lights under 2,000 K due to the alternating current. To combat this phenomenon use lights 2,000 K or above as they have larger filaments that don't have time to rapidly cool. You could also power your lights from a direct current source, use led based lights, "flicker-free" bulbs, or rely on the sun.

Do you have any helpful tips or advice to add? Then please share them with the Fstoppers community in the comments below.

[via B&H]

Log in or register to post comments

4 Comments

Andy Foster's picture

Useful video, just getting in to using video.

Just one question regarding shutter speed. Is the recommendation 2x the frame rate of the final output (ie 24 fps so 1/50s) or 2x the actual frame rate used when recording, eg if I shoot at 60fps (1/125s) and 120fps (1/250s) even though I will do my output at 24fps.

Roman Kazmierczak's picture

.

Taylor Osborn's picture

2x the actual recorded frame-rate. The timeline/output will be remain a static number i.e. 24p or 30p typically. That enables you to drop in various recorded frame rates on to the same timeline and go from there.

As for the lights, if you don't have 2K lights you can use software like Flicker Free (DigitalAnarchy.com) to fix the flicker in most cases. We've even used Home Depot shop lights and it's worked out fine for speeds of 240fps to 960fps. Of course, if you can shoot it right in the first place that's definitely better than fixing it in post. But if the budget isn't there for good lights or you can't control the lighting, flicker is something software can usually fix.