More Slow Motion questions
 

Hello community of geniouses:

I have a potential client that asked me for some tests for slow motion for a music video project that will contain 85% slow motion and 15 % regular footage. I performed two of them: HD in 24P and SD in 60P. He wanted to do it in 16mm, but a common friend that has done some works with me told him that the HD-100 will give him what he wants or exceeds in terms of resolution/visual performance. Plus, no messing arround with film, development cost, etc.

Without a doubt, the HD looks much more "high definition", but too strobbing when slowered down to 60%. SD was GREAT, but was, well, just SD... We are trying to compete with 16mm film. By the way, he was extremely impressed with the resolution and he is sold on HDV!

His project cannot afford the HD-SDI card route. Any other trial already done by anybody that can be shared as to how to get a better Slow Motion performance using HD? One test I did not performed, but by logic will yield better results, will be HD 30P, but I do not think it will give us the clean result 60P gave. Any comments are very welcommed, including parameters for shutter speed!

Luis Otero

If it is a music video, then HDV-SD60P shouldn't be an issue. MTV doesn't broadcast HD yet do they?

Shooting 30P will give you a 80% slow-motion speed when you bring it back to 24fps. 60P gives you 40% slow-motion speed when you bring it back to 24fps.

As a general rule, set your shutter speed to at least 1/100 (preferably 1/120)when shooting 60P. The higher the shutter speed, the sharper the image.
For a contemporary music video "no-motion blur" look I would probably recommend at least 1/200 for 60P, and 1/100 for 24P.

Tim,

Thanks for your always sharp and clear advice!

Luis

Luis.

What about shooting the slowmo in 50P, it will give you 20% more resolution (576 lines instead of 480) and resolves to exactly 50% speed when played at 24fps.

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Paolo

I forgot to mention 50P. It works well too. However Luis, if you are to use HMI or Kino-Flo lighting, make sure you dial in 1/60 or 1/120 shutter speed when using 50P to avoid flicker. Puerto Rico is a 60Hz region right?

So, this 720p/50 working in Canada too? I mean insight in the hall. If yes, which sutter speed I need to use?
Also outside, where I don't use any light, it's OK to shoot 50p?

Tim, please let me know.

LaszloNo flickering?

I would imagine that flickering with 50p has to do with electricity running at 60Hz in some countries. Thus you should be fine with 50p outside since the sun isn't 60Hz.

Have you tried taking your 24P (30P would be better if going HD) and slowing it down with After Effects using time remapping? The slow motion you get in editing doesn't compare to the same effect done in programs designed to re-time footage.

Yeah it works fine. As Tim Gray said, outside with sunlight wouldn't make a difference. Tungsten lighting should be fine as well.
However, if you are shooting 25P or 50P while using HMI or flourescent lighting in Canada/U.S. or other 60Hz regions, then set your shutter to variable, and then adjust it to 1/60 (1/59.92 or 1/60.01) or 1/120 (1/120.1 or 1/119.4).

Thanks guys!

Laszlo

Tim,

Thanks for this information, and thanks to everybody else for taking their time and providing your input.

As to AE, I never have done it, so could you please let me know (in general) the steps to do the time remaping using it?

And, yes, Puerto Rico is 60 Hz. The music video, as far as I know, will use tungsten and fire for ilumination (night scenes only), so I am pretty shure no HMI will be used.

Again, thanks for your comments.

Luis

isn't it just easier to apply a filter in post? or is it hard to do that in hdv?

Brian,

As far as I know there is no filter perse for time slow motion effect. You either shoot at higher frame rate and slow it down in post (60fps running at 40% in a 24fps timeframe) or slow down the footage taken in 24fps to 60%. The problem with the second option is that the final product is not as clean as the first option. That is my dilema: the HD-100 does not record to tape 60fps; its highest frame rate is 30fps. In SD it goes to 60fps, but does not give you the 720P, only 480p. If you use the component output with the AJA card, you can get it, but you need to add cost to your production, wich is the opposite of what we are looking for.

If there is a "filter" out there, please let me know since I am trying to experiment with as many solutions as posible for my client.

Thanks,

Luis

PS

I have MotionPerfect from DynaPel, wich expands or contracts footage to conform it to whatever is your desired final frame rate, but the outome footage is kind of funny arround the edges of the fast moving object (kind of rippling water).

Twixtor will interpolate frames and create new in-between morphed frames, but it still isn't temporally quite as good as overcranking in the first place. Also, there is a bit of a learning curve with Twixtor. You can download a demo.

It's not a matter of HDV, the fact is that a software trick will just double the existing frames and it will add some interpolated frames with, possibly, some frame blending. It's OK but it doesn't create the real slow-mo effect. Think of filming a stone being thrown into a lake. The dynamics of the stone hitting the water surface, the water ripples and splashes, all that stuff can't be captured at standard speed and then slowed down effectively. On the other hand, if you overcrank you actually capture more "events", events that you can watch later at slower speed.

Hope this makes sense :)

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Paolo