One of the most important features that many of us look for when buying a camera is undoubtably variable frame rates, specifically 60p. We want to be able to capture slow motion and the only way to properly get it is to over crank – which means shooting more frames than you need so that you can slow it down in post without skipping frames. Unfortunately, many great cameras today such as the Blackmagic Cinema Camera or Canon C100 don’t have a 60p option, and make our lives difficult as we are forced to rent specialty gear whenever we need slow motion. The good news is that many cameras lacking in 60p do have a 60i option available, and while you may have avoided it like the plague in the past, this post will show you how 60i can become your new best friend.
For those of you that haven’t shot in 60i or 60p before, let me briefly explain the difference. 60i represents 60 interlaced FIELDS (not frames) – well actually 59.94 to be exact. 60p on the other hand, represents 60 individual FRAMES which are complete images in themselves. They may sound similar, but they are very different. If you’ve ever shot something on tape and ingested it into your computer, you probably know what fields look like. You might have seen an image that looks like this when paused:
When working with true 60p footage, you can slow it down to 40% on a 24p timeline, and it will play back in perfect slow motion, giving you beautiful results. 60i on the other hand, can’t just be dropped into a 24p timeline and slowed down because it takes two fields to create one frame, meaning you really only have 30 frames to start with, not 60. If you were to attempt slowing down a 60i image to 40% it would look as bad as slowing down a 30p image to 40%. There just wouldn’t be enough frames to cover the reduction in speed and you would get very jumpy footage.
With all that said, there is a way around this and in FCP X it is ridiculously simple.
All you need to do is select your clip in the event, click on the inspector, and change the view to ‘Settings’. From there, simply click ‘De-interlace’ and voila, your clip can now be treated as a 60p clip. In fact the inspector will automatically update to see the clip as a 59.94p file, rather than a 29.97i file.
You can now drop your newly converted 60i/60p clip into your 24p timeline, slow it down to 40% and you will have really nice slow motion.
The principle behind this, is that FCP X is de-interlacing your footage, and effectively converting it to a 60p clip before you slow it down in your timeline. You can do this manually with just about any software out there, but FCP X makes it really easy.
Is this as good as using a true 60p clip? Not really, but it’s not as far off as you might think. The image has less information in it than a 60p clip would have (since it’s using fields, not frames), but the motion should be nearly as smooth because each field is different, so FCP X is able to interpret those fields really well, effectively making new frames from them.
It’s important to remember though that when shooting 60i material, have your shutter set to at least 1/120, just as you would if you were shooting 60p. If you don’t do this then you won’t be able to slow down your footage effectively.
I’ll be releasing a commercial next week that was primarily shot in 60i on the C100 and will be sure to update this post with the final product so you can see how this works in action.
For you editors out there, be sure to check out my recent post on Achieving The Blockbuster Look When Color Grading.