Shutter angle/speed for 50p shot for 25p edit? GH5, Atomos Ninja Inferno, FCP X

[Noah Kadner]

Technically it will just do a speed change – whether it works aesthetically is subjective. Shoot some test footage.

Noah

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[John Wildgoose]

Thanks Noah, I will do that.
I was just interested in what exactly FCP does to the 50p in a 25p project to get it to play at normal speed! I know I maybe should not worry about what is going on under the hood, but I’m of that generation.

I’ll do some more tests. I am not sure if it’s anything to do with anything related, but I recently shot some 50p at 80th/s (at 8bit) and it just seemed a bit more natural. A little bit of softening through motion blur seemed to appeal. The test was dumped here

Thanks for your response, appreciated.

John

[Noah Kadner]

Yeah the higher shutter speed you go above double your frame rate the more staccato the results will look. To get from 50 to 25 FCPX just throws away every other frame- as you would expect.

Noah

FCPWORKS – FCPX Workflow
FCP Exchange – FCPX Workshops
XinTwo – FCPX Training

[John Wildgoose]

Hi Noah
…and in halving the frame rate it halves the shutter speed? This is crucial as the look of the clip is so clearly affected by the shutter speed.

I’m going out today to do some tests. People, water, foliage, traffic. Plus some varieties of shutter angle/speed at 50p to see exactly what happens when it’s kept at 25p in FCP X. I’ll also shoot 25p of the same scenes at half the shutter speed I shot the 50p at to see if there’s any difference between it and the 50p that doesn’t have the speed change applied.

I guess I am trying to prove the hypothesis that 50p shot at 100th/s but left at 25p in the FCP X timeline will look the same as 25p shot at 50th/s (or 80th/s and 40th/s etc). This will then dictate whether I can shoot everything at 50p and quit agonising!

I’ll be back I guess.

John

[Paul Golden]

At the risk of being impertinent, what’s the reason for wanting to do this?
While it sounds like some sort of problem solver to shoot at 50fps for use at 25, shooting this way is rarely done as a matter of course for several reasons:
1) Double the amount of data
2) Post processing headaches
3) No apparent benefit for most of the footage you shoot.

Unless you have a really good reason (need lots of slow motion), I can’t see why you’d want to shoot this way for normal footage. You asked a tech question and folks have answered it diligently, but I’d go back to the original reason of why you’d want do it if you don’t have to? It seems like overkill.

[Paul Golden]

I forgot one other reason not to: You need twice as much light! 🙂

[John Wildgoose]

Hi Paul
That’s a very fair point and I can see why many/most people might scratch their head at such a notion.

Maybe I should have explained why I wanted to do this, but to be fair to myself, the answer is so ingrained in my mind it never occurred to me! So my bad, I should have explained.

I’m a veteran of 30 years shooting stills, video is increasingly (and excitingy) becoming a bigger part of my remit these days and I am trying to get up to speed with all the endless and shifting (not to say expensive) technology.

One of the things that has become apparent is a need for ‘generic’ moving images. I’ve been asked to shoot stock and b-roll/cutaways for clients recently, enough to make me jump on this difficult/rewarding learning curve. For instance, one client has a web site full of interviews with industry experts and they decided their ‘talking heads’ needed spicing up. So they sent me off to Asia to shoot b-roll to cut into their web embedded videos. Sweet gig? Yes, but it did immediately highlight some shortcomings in my process, not to say my skillset.

If you have a few minutes (and a cup of coffee), here’s my cut from that Asia shoot. Please forgive the terrible ‘standards’ short comings. I’m a neophyte remember!

https://vimeo.com/157060331

As you’ll now hopefully appreciate, to be able to shoot all of that at 50p and make a choice in the cut what should stay 100% and what could go half speed would be a major advantage.

cheers
John

[John Wildgoose]

Twice as much light! Yes, but to be honest I shoot a lot with fast primes, often wide open, so anything that helps me dump light is a blessing!

Thanks Paul.

And re: your comment about diligently answered tech question. Yes, I have tried hard to make sure people who have contributed to help have had that help acknowledged. It’s a great forum, obviously brimming with good people who not only possess a huge amount of high quality knowledge, but are also happy to impart it for the good of all. Open source knowledge is a wonderful thing.

I will endeavour to ‘put something back’ in whatever way I can. Surely these 30 years have given me something to contribute!

[Claude Lyneis]

[Noah Kadner] “Yeah the higher shutter speed you go above double your frame rate the more staccato the results will look. To get from 50 to 25 FCPX just throws away every other frame- as you would expect.

Noah”

I frequently shoot at 60 p for sports (lacrosse) because it definitely improves the look when using slow motion, 50% speed. So the project is set up at 60 p and the motion looks normal. Is FCPX really throwing away every other frame or is it just running 60 frames per second? Generally the output is compressed using Compressor set up for Youtube. Once though Compressor, the quicktime inspector shows the frame rate to be 60 fps (59.94). So in this case it doesn’t seem to be throwing frames away. I guess if you have a 30 f/s video and you insert some 60p into it, it may shed frames and in this case you lose half of the light and get less motion blur.

[Kevin Rag]

Hey John,
What camera lenses did you use? I like the look:)

K