Stupid video question regarding fps

Raymond Lin

Raymond Lin

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Lets say I like to do some slow mo stuff, and my camera can do 120fps (5D4), so I shoot it at 120fps so I can play it back to 30fps and get a slow mo effect, and then I guess I can play it back "normal" too.

What is the disadvantage doing something like this vs stick shooting at 30fps, and lack the ability to do slow mo.
 
If you shoot at 120 fps you need a shutter speed of 1/240 which means more light/higher ISO. Playing back slow motion footage in real time can look different from normal footage due to the difference in shutter speed, although not everyone will notice this. Also, usually shooting in show mo means no audio is recorded.
 
CSB said:
If you shoot at 120 fps you need a shutter speed of 1/240 which means more light/higher ISO. Playing back slow motion footage in real time can look different from normal footage due to the difference in shutter speed, although not everyone will notice this. Also, usually shooting in show mo means no audio is recorded.
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So if I shoot everything in 120fps it will be silence?
 
In Adobe Premier Elements 14 that I have motion can be slowed down or increased within the editing suite if that is any help
 
You can slow down any footage but of you slow down a clip shot at 30fps it won't be as smooth as a clip shot as 120fps.

If you slow down 120fps footage by 4x you will still end up with 30fps. If you slow down footage shot at 30fps by 4x you will end up with 7.5fps. This will obviously not be a very smooth playback.

Sound is still recorded at 120fps, but obviously won't sound very good when slowed down.
 
Gaz J said:
Yes

5D4 doesn't record sound at high frame rates.

Also only records in HD.
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I don't care for 4k at the moment, I know it does 4k but in silly codec.

Do you know if in the market there is a lead that can goes from Rode Micro Mic to 5D4's 2.5" jack? as opposed to getting a 3.5 to 2.5" adaptor.
 
CSB said:
If you shoot at 120 fps you need a shutter speed of 1/240 which means more light/higher ISO. Playing back slow motion footage in real time can look different from normal footage due to the difference in shutter speed, although not everyone will notice this. Also, usually shooting in show mo means no audio is recorded.
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Not for slow mo.

If you use a 50% shutter @120, it will be a 12.5% shutter @30. Better to go for a 100% shutter (1/120).
 
Raymond Lin said:
Second question…24/25 or 30fps?
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Depends on where you are.

If you're shooting in the UK with 50Hz mains and have artificial lighting anywhere near the camera, shooting at 25, 50 or 100 will give you a fixed amount of light per frame.
 
If you look at the bit rates at the various resolutions and frame rates you will probably see that the bit rate at 120fps is similar the the bit rate at 60fps so each one of your frames will have much higher image quality at the lower fps there is normally a sweet spot of resolution and fps where you are getting the maximum amount of data spread across the minimum of frames.
 
ah5168 said:
If you look at the bit rates at the various resolutions and frame rates you will probably see that the bit rate at 120fps is similar the the bit rate at 60fps so each one of your frames will have much higher image quality at the lower fps there is normally a sweet spot of resolution and fps where you are getting the maximum amount of data spread across the minimum of frames.
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The camera doesn't use an intra frame codec, so frame rate and bit rate aren't linearly related.

The codec records the difference between frames, the higher the frame rate, the less difference.
 
Raymond Lin said:
Second question…24/25 or 30fps?
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if you're in the UK, then 25 - unless you have a specific reason to shoot in 24. 30 is just for NTSC regions really.....

I made the mistake of shooting 30fps for smoother footage on YouTube. All my videos seemed ok, until London Christmas market when I noticed flickering on the lights... So now I only shoot 25fps unless I'm in the states.
 
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RandomlySet said:
if you're in the UK, then 25 - unless you have a specific reason to shoot in 24. 30 is just for NTSC regions really.....

I made the mistake of shooting 30fps for smoother footage on YouTube. All my videos seemed ok, until London Christmas market when I noticed flickering on the lights... So now I only shoot 25fps unless I'm in the states.
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Going to be filming in Japan...
 
Not exactly what you're asking but thought I'd link the video below as it's a good way to do a speed ramp if you intend to :

 
Raymond Lin said:
Going to be filming in Japan...
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Depends where in Japan. Parts were electrified by Germany at 50Hz, parts by America at 60Hz.

Find a map of the areas, record at the mist common frequency and accept flicker in the other regions, or do what Japanese broadcasters do and hire some time on a For-A or Snell Alchemist PH.C.
 
st599 said:
Depends where in Japan. Parts were electrified by Germany at 50Hz, parts by America at 60Hz.

Find a map of the areas, record at the mist common frequency and accept flicker in the other regions, or do what Japanese broadcasters do and hire some time on a For-A or Snell Alchemist PH.C.
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Lol, that's going to be PITA.

half the time will be in Tokyo, I guess I just have to google the region by region.

http://www.japan-guide.com/e/e2225.html

Looks like outside of Tokyo I will be shooting in 30fps and then 25fps in Tokyo. Who knew electricity grid affects filming ! Learn something new everyday.
 
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I just tried the 5DIV in 60fps using ALL-I with a Rode Mic, and it can record sound at 60fps !! sweet !
 
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