As I understand, modern film and audio are synced using SMPTE timecode which is embedded in the metadata of the respective source files. Modern clappers also display the timecode, but they still have the clapper bar. Is it really necessary to actually clap the clapper anymore?
If you can afford a timecode slate setup, no, it's not necessary, though the action of clapping the slate can serve a couple of purposes:
- It is a small signal to the editor (well... usually his intern, anyway) that there is audio to look for.
On MOS takes (takes without sound), the slate is not clapped (because there's no sound) there's also usually (but not always) a spot on the slate that says "MOS" that gets circled to show there's no matching audio file.
- It's a backup system. If, for some reason, the timecode encoding fails, having that slate clap can save you a lot of time.
That being said, the setup for a timecode slate can be expensive, particularly for small budget projects where a $300-2000 slate is half of... if not the entire... budget... and that doesn't include the cost of all of the timecode controllers/sync boxes that are needed to sync the audio and camera/s together. A full setup could easily cost $5000.
There are certainly cheaper options. In fact, there are a couple of relatively reputable iPad apps that are being used on set so, if you've already dished out $400+ for an iPad/iPhone, you may have this option, but you still need to be able to sync the iPad with the audio equipment. Regardless, if you think about it, you can't clap an iPad, so clearly, it's unnecessary... though, you can certainly buy a clapper case to go with it.
So, for the peons who can't afford (or don't want to waste money on) a timecode slate, you buy a $10-50 plain old whiteboard slate and clap it to your heart's content.
*I have never used any of the linked devices/apps and my inclusion of them should not be considered support of the product's quality