Tuesday, July 26, 2011

24p or 30p?

I'm doing pre-production planning for a documentary, and one of the first questions I've been trying to answer is; 24p or 30p? To be honest, I don't usually give a lot of thought to what format to use for short projects, but since this is going to be a fairly "big" one, I decided that I should think about whether I want to risk shooting at 24p, which is not a format I have used much.

I dropped Jared Fleischer an email asking him what he was shooting in. He's in the middle of his second documentary feature, Sourlands, which he is shooting with the Panasonic GH2.

This is what he had to say:
I'm shooting mostly at 24p (I'll explain "mostly" below.) I did spend some time thinking about frame rates before deciding on 24.

-The big benefit of 24p, obviously, is that it looks the most filmlike. And since I'm going for other filmlike qualities by using a DSLR, it seemed like 24p was the right choice.

-Another small benefit to 24p is that in the very very unlikely event that the documentary gets picked up theatrically, I'll have a much easier time doing a transfer.

-And finally, to my knowledge, there's no such thing as 30p on Blu-ray, it's all 24p or 30i. If I'm correct about that, then I think that should definitely steer you toward 24p.

-The benefit to 30p that I see would be that there's more smoothness and less jerkiness to the shot, which can be especially useful in run and gun type documentaries. But here's what I do when I need a smooth shot: I shoot in 24p and just change the shutter speed to 1/60 or 1/100 instead of the usual 1/50. And when I need slow motion, I shoot in 60p and then slow it down by 60%.

-As I mentioned in my last blog post, sometimes when I'm shooting with the Panasonic GH2 I shoot in program mode, which means the shutter speed is always changing. I'm pretty sure that I can tell when it jump outs of 1/50 to 1/60 or 1/100, but I bet no average viewer would ever notice. Still, to my eye, I think that 24p with a 1/50 (or 1/48 to exact) shutter really does look the best. It look likes a movie.

See also:
NotesOnVideo: Documentary Shooting with the Panasonic GH2
Kickstarter: Sourlands: A Story of Land, Energy and a Life More Local

Blu-ray doesn't do 30p
I hadn't even thought about Blu-ray (my current distribution plans are YouTube and DVD) but Jared's comment about Blu-ray surprised me. A quick bit of research confirmed that while DVD's support 30p, Blu-ray supports only 24p and 60i.

Also a little bit troubling is the report from a DXUser contributor that converting from 60i to 30p resulted in some loss in color:
Converting 30p to 60i and burn as a 60i BD: Preserves temporal resolution, but reduces color subsampling significantly.

DXUser: Shot 1080 30p -> 24p or 60i for Blu-Ray?
AVSForum: Bluray does not support 1080p30!! Did not know this!



FocusPulling (.com) said...

Jared Fleischer's credibility is questionable. He recommends shortening the shutter speed to improve the look when panning quickly. This is the wrong and opposite advice; cinematography 101. No further explanation necessary.

About the Blogger said...

Hey H Paul --

Jared here, read your comment and have to respectfully disagree, just based on what's worked for me. (Though I think, yeah, "smoother" wasn't the perfect word for me to use in my email to Michael.) Using a 1/100 shutter speed at 24p, when hiking through the woods handheld behind bird researchers twisting and turning quickly on trails, has without a doubt produced footage on the GH2 that's more watchable than at a 1/50 shutter speed, and certainly more watchable than at a slower shutter speed. The 1/100 stuff looks less blurry and the 1/50 stuff looks more blurry. My take on it is that motion blur is what turns people's stomachs on very fast pans and bouncing handheld shots, not the strobiness of a faster shutter speed. I've tested all sorts of shutter speeds and I wouldn't change to 1/100 if I didn't think it looks better for some shooting situations -- which sometimes it does.

Shoot me an email if you'd like to discuss further. I'm only a couple years into this and I'm certainly always trying to learn more: