Not Shooting 720pN - Am I MAD?

A

andynick

Well-known member
Some of you may have seen from previous posts that I'm getting down into the mud with loads of dogs at the moment - very fast action and pretty spectacular!

I want to do some SloMo and I'd LIKE to do some Speed Ramping - but of course I can't do Speed Ramping with the HVX200 . . . or can I?

Soon after getting my paws ( ! ) on the HVX, I realised that much as I'd like to shoot "Native" to save valuable P2 space, I'd shoot one (difficult to repeat) scene and wish I'd shot it at the other speed!

So I decided to shoot everything at 50fps (50Hz territory here) then Duplicate every suitable QT file. That way I can simply use Cinema Tools to Conform "Clip A" to 25fps for my 50% speed - and use Compressor's Advanced Format Conversions to convert "Clip B" to 25fps (without speed loss).

I've tried it and although it's a little laborious and Disc-Space Ravenous, it effectively means I get the option of 100% or 50% speed on the same take - and no rendering required for either clip in my FCP Timeline!

What I haven't yet tried is Ramping "Clip B" down to 75% at (say) frame 199, then starting from the next frame (400?) (I'm hopeless with figures) Ramping the SLOW "Clip A" from 125% down to 100% so that I get an apparently seamless "ramp" from 100% to 50% of the original speed . . . (is anyone still here)?

The idea, of course, is to use as little software speed changing as possible on each of the clips.

1) Does this make sense?
2) Is there an easier way?
3) Is it WORTH the hassle?
4) Should I take up fishing?

Andy
 
the best way to achieve speed ramps is in after effects. it also has nice frame interpelation. you can do it in fcp but it does not ramp the sound, which is sometimes the best part.
 
Shooting 50fps, and showing every other frame, will give you a direct simulation of having shot 25fps (assuming that you used a 1/50 shutter). So yes you can have your 25fps main shot and your 50fps slow-mo in the same shot.

There is no in-camera ramping. As for the smoothness of ramping, the more frames you have to work with, the smoother the end result will be. It won't match a "true" ramp, but it'll be better if you start from the 50fps source than it will be if you were to start from a 25fps source, that's for sure.

So, in essence, I think you're probably on the right track for what you want to do. The only real consideration is your shutter speed, because a film camera (or a true ramping video cam like the VariCam) can adjust the shutter along with the frame rate while ramping; with your method you're going to have a constant shutter so you'll either:
1) go with 1/50th for everything, which means your 25p will look fine but your slow-mo will be somewhat blurry;
2) go with 1/100th for everything, which means your 25p will look choppy but your slow-mo will be proper (and everything will be 1-stop darker)
or
3) go with 1/75th and try to meet in the middle.

Or, if you know at what point you want the ramp to begin, you could change shutter speeds using the scene file dial, but I would imagine this would be more hassle than it's worth...
 
Barry_Green said:
1) go with 1/50th for everything, which means your 25p will look fine but your slow-mo will be somewhat blurry;
2) go with 1/100th for everything, which means your 25p will look choppy but your slow-mo will be proper (and everything will be 1-stop darker)
or
3) go with 1/75th and try to meet in the middle.
Click to expand...
If there's one person I really hope will reply to my posts it's Barry Green.
Thanks Barry - once again, that's very reassuring and solid advice.

As an (essentially) stills photographer, the thought of shooting any moving subject at 1/50th makes me shudder but I've learned that stills and video can be poles apart (at times).

Even 1/100th makes me wince!
But of course you're right - I've already noticed that the slowed footage looks blurry, so I'll experiment with 1/75th and see what happens.

Or, if you know at what point you want the ramp to begin, you could change shutter speeds using the scene file dial, but I would imagine this would be more hassle than it's worth...
Click to expand...
You can say that again - I'm already fully occupied when shooting action - and anyway, the whole point is that I don't know prior to shooting whether I'll want slow-mo or not - that's why I want to hedge my bets.

But I may have a trump card - I have Apple's (fabulous) Shake, so I think I may be able to bring the 50fps footage straight into Shake (If I can just get my head around it) and do all the necessary speed ramping there.

There won't be too much of it after all. Too much slow motion is really crummy.

go with 1/100th for everything . . . (and everything will be 1-stop darker)
Click to expand...
OUCH!
I'm still smarting from that one, Barry!!

Andy
 
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