Jump to content




Photo

what is the cause of the jittery footage?


  • Please log in to reply
14 replies to this topic

#1 Nitai Lev Oren

Nitai Lev Oren
  • Basic Members
  • PipPip
  • 39 posts
  • Cinematographer
  • Israel

Posted 24 June 2016 - 04:41 PM

I saw somebody asks about a footage from 700d camera shot on 1/50 24fps and it looks jittery what is the cause of this?


Edited by Nitai Lev Oren, 24 June 2016 - 04:43 PM.

  • 0




#2 Landon D. Parks

Landon D. Parks
  • Basic Members
  • PipPipPipPip
  • 1627 posts
  • Producer
  • Cincinnati, Ohio

Posted 24 June 2016 - 11:53 PM

'jitter' is a loose term, but one I would not apply to digital cameras. Probably referring to frame rates in collaboration with an odd shutter setting, which can create image issues like ghosting, smearing, flicker, etc. 'Jitter' is something I associate with bad registration on film cameras. 


  • 0

#3 Nitai Lev Oren

Nitai Lev Oren
  • Basic Members
  • PipPip
  • 39 posts
  • Cinematographer
  • Israel

Posted 26 June 2016 - 03:14 AM

so I can call it stuttery footage.

the shutter speed is ok

what do you think is the problem?


  • 0

#4 Landon D. Parks

Landon D. Parks
  • Basic Members
  • PipPipPipPip
  • 1627 posts
  • Producer
  • Cincinnati, Ohio

Posted 26 June 2016 - 05:19 AM

1/50 at 24p should produce identical motion blur to a 180 degree shutter. You shouldnt be seeing a lot of flicker, though 24/180 does produce a film like motion blur different from higher rates and shutters.

First, Id try moving the shutter speed up and down to see if that cures it.

Im not real sure other than that. Flicker shouldnt be terrible as long as shutter and frame rate is in synce. Could even be a mechanical problem.

Have you tried resetting the camera via the settings menu? If that don't work - you might try to upgrade or reinstall firmware.

Edited by Landon D. Parks, 26 June 2016 - 05:21 AM.

  • 0

#5 Nitai Lev Oren

Nitai Lev Oren
  • Basic Members
  • PipPip
  • 39 posts
  • Cinematographer
  • Israel

Posted 26 June 2016 - 07:39 AM

it's not flicker it's jitter or choppy footage I don't know how to call it. 


  • 0

#6 Tyler Purcell

Tyler Purcell
  • Sustaining Members
  • 2363 posts
  • Other
  • Los Angeles

Posted 26 June 2016 - 11:31 AM

I saw somebody asks about a footage from 700d camera shot on 1/50 24fps and it looks jittery what is the cause of this?


The only way to diagnose is to post a sample.
  • 0

#7 Landon D. Parks

Landon D. Parks
  • Basic Members
  • PipPipPipPip
  • 1627 posts
  • Producer
  • Cincinnati, Ohio

Posted 26 June 2016 - 01:34 PM

Bottom line is: The 700d, reset to factory settings, shouldn't produce any choppy footage. If it a camera setting that has been skewed, resetting those settings should clear that back to factory. If it still has choppy footage despite factory settings, more than likely it's a faulty camera that will need to be repaired.

 

I've never heard of any camera setting causing choppy footage - other than maybe trying to shoot at a very low frame rate - which the 700d does not do. It's more than likely an issue with the settings being mismatched.

I'd love to see the footage though - so I can tell what is meant by 'choppy'.


Edited by Landon D. Parks, 26 June 2016 - 01:35 PM.

  • 0

#8 David Mullen ASC

David Mullen ASC
  • Sustaining Members
  • 18789 posts
  • Cinematographer
  • Los Angeles

Posted 26 June 2016 - 04:53 PM

24 fps is more stuttery, more strobing in motion than traditional 60i video.  Some people used to the traditional video look balk at the look of 24P, even though film has the same motion look if shot at 24 fps with a 180 degree shutter.

 

Now it also depends on how it is viewed in playback, sometimes when watching 24P on a camera's LCD, the refresh rate is low enough that the 24P strobing motion is more distracting than usual.


  • 0

#9 Nitai Lev Oren

Nitai Lev Oren
  • Basic Members
  • PipPip
  • 39 posts
  • Cinematographer
  • Israel

Posted 26 June 2016 - 05:57 PM

ok, I have another question if I want to do long exposure (like in this picture - this is not mine) on my DSLR but in video not stills

I was told I cannot do that on a DSLR is this true?

Attached Images

  • long-and-short-street.jpg

Edited by Nitai Lev Oren, 26 June 2016 - 05:58 PM.

  • 0

#10 Landon D. Parks

Landon D. Parks
  • Basic Members
  • PipPipPipPip
  • 1627 posts
  • Producer
  • Cincinnati, Ohio

Posted 26 June 2016 - 06:46 PM

This is a shutter-speed trick that can work in both photo and video. I haven't used a 700d, but on my GH4 I can adjust the shutter speed and make this happen. All you need to do is slow the shutter speed down, from say 1/50 to 1/30 or maybe even 1/24. Do keep in mind that doing so will also allow more light in - so you'll need to make up the difference in ND's or stopping the lens up. 

All it is doing is keeping the shutter open for a longer open of time, making the light streak.

 

Some camera's might not allow you to set a really low shutter speed though. Going too low you'll start to see other strange artifacts in video. There also comes a limit where the sensor can read the correct FPS while still keeping it open for exposure. There is no such requirement in stills, but when the sensor is trying to capture 24fps, there comes a point where the shutter needing to close for the next frame will override your shutter speed.

 

I believe I have went as low as 1/24 @ 24p on the GH4, with some nice results at a waterfall.


Edited by Landon D. Parks, 26 June 2016 - 06:50 PM.

  • 0

#11 David Mullen ASC

David Mullen ASC
  • Sustaining Members
  • 18789 posts
  • Cinematographer
  • Los Angeles

Posted 26 June 2016 - 07:01 PM

To get that much streaking of lights, you need to drop down into time-lapse levels of low frame rates, which then allow for very long exposure times per frame.  So absolutely a DSLR can do this, many people shoot time lapse on DSLR's.  It's the shutter time that is causing that much streaking, and at 24 fps, it is physically impossible to expose each frame for longer than 1/24th of a second since the camera has to shoot 24 frames every second.


  • 0

#12 Landon D. Parks

Landon D. Parks
  • Basic Members
  • PipPipPipPip
  • 1627 posts
  • Producer
  • Cincinnati, Ohio

Posted 26 June 2016 - 07:33 PM

David is correct on that. While you can get some descent results in video mode, you will not achieve that level of exposure. You'll need to be in stills mode and set it to time-lapse. Of course, when you play those back at 24p you'll find the footage moves REALLY fast. 

 

I believe my GH4 can do 11 frames per second in stills mode, so on a GH4 you'd expect at least a 2x speed ramp. The slower the shutter, the less frames you can capture a second.

 

That still image you posted above was likely shot with a 1 second shutter or maybe event longer. That will practically be unusable for video work - though it is possible, if 24x faster than real-time footage is acceptable. 


Edited by Landon D. Parks, 26 June 2016 - 07:36 PM.

  • 0

#13 Nitai Lev Oren

Nitai Lev Oren
  • Basic Members
  • PipPip
  • 39 posts
  • Cinematographer
  • Israel

Posted 27 June 2016 - 01:55 AM

so let me understand that correct if I have a 60D camera

I put to timelapse mode on Magic Lantern?

because I switched to 24 fps and shutter 1/24 but the cars won't smear

to get the cars like light strikes I must do it on timelapse?


  • 0

#14 Landon D. Parks

Landon D. Parks
  • Basic Members
  • PipPipPipPip
  • 1627 posts
  • Producer
  • Cincinnati, Ohio

Posted 27 June 2016 - 07:18 PM

You won't be able to achieve the same streaking effect in video mode, no. You can replicate it a little - but it will not look anything like that still you posted. For that, you'll need to set your camera to photo mode in either time-lapse or continues shooting mode. You'll then need to get the most FPS you can while exposing for the streak. In reality, for that level of streak I'd start at a 1-second shutter speed. This of course means if you put that into a 24fps video timeline, your footage will play back about 24x faster than your regular footage.

 

It's a trade off, but there is not really another way to achieve that look. 


  • 0

#15 David Mullen ASC

David Mullen ASC
  • Sustaining Members
  • 18789 posts
  • Cinematographer
  • Los Angeles

Posted 27 June 2016 - 07:42 PM

The longer the shutter time, the longer the streak, and the streaking at 1/24th of a second isn't as extreme as in the example you posted.


  • 0


CineTape

Pro 8mm

Aerial Filmworks

Ritter Battery

Abel Cine

Paralinx LLC

Willys Widgets

Tai Audio

Technodolly

Broadcast Solutions Inc

CineLab

Rig Wheels Passport

The Slider

Zylight

rebotnix Technologies

Glidecam

Visual Products

Zylight

Broadcast Solutions Inc

Aerial Filmworks

CineTape

Ritter Battery

Rig Wheels Passport

Visual Products

CineLab

rebotnix Technologies

The Slider

Willys Widgets

Pro 8mm

Technodolly

Abel Cine

Tai Audio

Paralinx LLC

Glidecam