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Slow motion confusion on DSLR


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#1 Afolayan Dammy

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Posted 21 January 2015 - 04:57 AM

I am about to shoot a music video on a canon 5D or canon 7D the final edit on the music video may have lots of slow motion. The confusion now is frame rate and resolution. I know to get super smooth slow motion i need a higher frame rate. And to get 60fps on canon 7D you can only shoot at 720p while you can only get 24 or 25fps on 1080p. Should I go with the 720p just to be able to get 60fps or should i go with full HD 1080p. Will slow motion go well on it. Which would you advice me to go for.


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#2 John E Clark

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Posted 22 January 2015 - 05:55 PM

You would have to see if shooting at 720p @ 60 fps does the slomo you want, then if the uprezing to 1080p to match the rest of your project 'works'... that is not so obvious as to look faked up.

 

60 fps only gives you a bit more than 2x, the slomo scenes in 'hollywood' productions are done at much higher frame rates, and attended increase in illumination. For each 'stop' of increase in the shortness of the shutter speed for the higher frame rate, one needs to double the light. So if you were 'ok' at 1000W @ 24 fps, you'd need 2000W at 2x the frame rate, etc. You can fiddle with the shutter speed a bit at higher frame rates, but for maintaining a 180 deg shutter, need to up the light.

 

There may be some sort of 'software' that simulates higher frame rates, which you can search for and see if that solves your problem... although it may have to be 'freeware'... if budget is a problem.

 

That or rent a camera with a higher frame rate at 1080p


Edited by John E Clark, 22 January 2015 - 05:59 PM.

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#3 Satsuki Murashige

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Posted 22 January 2015 - 09:42 PM

What's the subject that you are shooting in slow motion? 60fps played back at 24fps works well for slowing down action like a person walking across the street or lips moving as someone is talking. A subject that moves faster than that will probably require a higher frame rate if you want a visible slow motion effect.

Sometimes, you can cheat an actor's motion by having them perform an action slower and also shooting in slow motion for an exaggerated effect. Imagine the classic close-up slow motion shot of an actor shouting, "Noooooo!" You can shoot it at 60fps, and then have the actor perform twice as slow as he would in reality, giving you same effect as if you shot 120fps (as long as nothing else in the frame moves to give away the illusion).

The Sony A7S, GoPro 4, and iPhone 6 will all do 120fps at varying resolutions and are cheap enough to buy. The Sony FS700 is cheap to rent and will do a decent 240fps at 1080p with not too much aliasing.
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