Big deal about slow motion / 60fps???

S

spikeman256

Active member
I'm totally new to all of this, so go easy on me...

My only experience with slow motion is watching it on TV & movies (very nice) and then playing back on a VCR, DVD, or Tivo in slo-mo mode...the latter three being mediocre at best.

From what I understand, the least expensive camera to offer slow motion before the hvx-200 was the Varicam which is apparently $80K+/-.

Considering this, I hear people getting excited and getting ready to do backflips over the varible frame rate capability of the hvx-200...watching Barry's first DVD last night, I see that slow motion has only a handful of different speeds...the slowest being 60fps...

isn't that just 1/2 speed? Is that really *that* big of a deal?
I'm not saying it's *not* a big deal...I'm just asking.

32, 36, 48, and 60...without knowing much about this stuff, I would've assumed that you could vary it from 30, 31, 32, 33, 34, 35, 36, etc...all the way to, I don't know, maybe 200fps or something???

Also, can't you make something slow-motion while editing it???
 
Looks like you've got some reading to do.

Yes you can do slo-mo in editing, but that is only doubling the existing frames.

With 60p, you have twice as many frames. Go watch slo-mo of a snowboard/skier and see how the snow looks, and the silky smooth & detailed shot?

See the Matrix where the coat waves in the wind as he dodges in slow mo?

Try and get that shooting 29.97 and changing to 50% speed in post. Will not look nearly as good.

60p footage looks beautiful.

50% is a very good slo-mo, yes you can get slower. Maybe the next version will do 90p in 1080p mode, that would be nice. But for now 60p is great.



You can read up on this and also search for sample 60p footage.
 
If you shoot 60 over 24P using a NTSC camera, it's actually 2.5x slowmo. It may not sound like much, but these are discrete frames produced by the camera with no interlacing artifacts and proper shutter speed etc., and it looks great.

If you need something slower than that, you can still combine it with postprocessing, but then you will take a quality hit.
 
Shoot something in 24pN with the shutter off or 1/50. Then shoot something in 60p over 24pN (in the scene file settings) with shutter of 1/120 or 1/250. Be sure to open the iris to match the exposure. Then play back both and prepare to be amazed. 24 vs. 60p is a 1:2.5 ratio so you get 2.5x slow-mo when displaying at 24fps.
 
Actually, if you're shooting at 24p like most of us, 60p will give 2.5 as many frames.

You're asking the difference between in camera slow motion and post slow motion. Both are worthwhile techniques and niether is "better' but it's nice to have both.

Slow motion in editing doubles the frames. The result is something that is slower but jerkier. Essentially what you are doing here is extending the length of time the image is on screen. Thus, I find this technique most useful when you simply want to emphasize power composition or an otherwise power shot.

In camera slow motion is when you actually double (or more) the number of frames per second that is recorded and then play back at normal speed. Here, you are actually extending the time it takes the motion to complete itself and also getting more detail on the motion in the shot. It's best used when you want to show off anything involving a lot of motion, whether it be a fancy kung fu movie, some crazy sports stuff, or watching individual drops of water hit the ground.
 
You can also shoot any frame rate from 2 frames per second to 60 in one frame increments. There is a way of doing this which is not in the manual. There are other threads that discuss this "hack".
 
Don't forget, if you use the slo-mo in camera, you can still take it even farther in post with better results then regular speed footage alone.
A lot can be done with today's Edit Systems. But shooting properly can help.
 
1st - Thank you to Ben...that was a great comparison...I appreciate you taking the time to put that together.

OK, so 60fps @ 24p gives 2.5x slo mo...that makes sense. 24*2.5 = 60.

Filmguy123 made a reference to the slo mo in Matrix...a agree, *that* slo mo looked great, but surely that type of stuff isn't filmed @ 60fps...right???

Sounds like the bottom line is this:

a - Slow motion in post looks pretty crappy...at least excessive use of it.

b - 60fps / 2.5x slower isn't the best money can buy, but it's the best that $5,000 can buy.


Is that a valid summary?
 
Actually there are cameras that shoot 100,000's of frames per second when there is enough light. Scientific hardrvive cams. I was recently on a shoot where they shot 360fps 35mm.. went through the mag lickety split...
 
From Wiki - "High speed cameras can film up to 250,000 frames/s by running the film over a rotating prism or mirror instead of using a shutter, thus reducing the need for moving parts. " Sky is the limit but the amount of light you need is not "practical" - Practical limit is 15,000fps.
 
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