Jump to content


Photo

About Flicker


  • Please log in to reply
5 replies to this topic

#1 Ryoma Kohari

Ryoma Kohari
  • Basic Members
  • PipPip
  • 11 posts
  • Cinematographer
  • TOKYO, JAPAN

Posted 01 April 2007 - 08:29 AM

Simple question.

We'll shoot under the regular fluorescent lights(not kinoflo or HMI) with 24fps and shutter
angle is 90 degree. The area where we will shoot has 60hz.

I'm not sure I will get a flicker thing on the film.

Would anybody answer this or tell me any info about the flicker things??
  • 0

#2 David Mullen ASC

David Mullen ASC
  • Sustaining Members
  • 19765 posts
  • Cinematographer
  • Los Angeles

Posted 01 April 2007 - 10:00 AM

If you are shooting crystal-sync 24 fps, probably not.

As the shutter angle closes down, you capture less of the sine wave. At 180 degrees, you get more than two pulses; at 144 degrees, exactly two pulses.

At 45 degrees, you get less than a full sine wave, so the problem is that every time you trigger the camera, you may be in sync with the peak or valley of the wave, so your exposure will be different each time.

But 90 degrees is probably fine. I've done it in the past with no problems.

jamrock, you need to go to My Controls and edit your Display Name to a real first and last name, as per the forum rules listed when you registered.
  • 0

#3 timHealy

timHealy
  • Basic Members
  • PipPipPipPip
  • 1252 posts
  • Other
  • New York

Posted 01 April 2007 - 10:21 AM

Very rarely, older flurescent fixtures can flicker. I caught one once when we started rolling. it could not be seen by eye but it could be seen in the video tap monitor flickering once we were rolling. I am not talking about shutter flicker. The flicker could not be seen through the eyepiece either. We did one take with that particular bulb out and sure enough when we got our dailies back that one fixture had been flickering the whole time. So they used the one take with that bulb out.

Once in a while you can see a flouro flickering in a movie. I was wondering if anyone had any tools or methods to try and test for fluoro flicker? David?

Best

Tim
  • 0

#4 David Mullen ASC

David Mullen ASC
  • Sustaining Members
  • 19765 posts
  • Cinematographer
  • Los Angeles

Posted 01 April 2007 - 10:23 AM

I think there is a B&S flicker meter.
  • 0

#5 Ryoma Kohari

Ryoma Kohari
  • Basic Members
  • PipPip
  • 11 posts
  • Cinematographer
  • TOKYO, JAPAN

Posted 01 April 2007 - 11:31 AM

Thanks for your info, David and Tim.
It's a big help for me.

I'm still researching about the relation of flicker, shutter angle and FPS.
I need to completely make it clear about it.
If I got some questions, I'll make a topic again.

I changed my name to real, sorry and thanks for your notice, David!

Edited by Ryoma Kohari, 01 April 2007 - 11:32 AM.

  • 0

#6 Jim Feldspar

Jim Feldspar
  • Basic Members
  • PipPipPipPip
  • 288 posts
  • Student

Posted 01 April 2007 - 12:38 PM

Simple question.

We'll shoot under the regular fluorescent lights(not kinoflo or HMI) with 24fps and shutter
angle is 90 degree. The area where we will shoot has 60hz.

I'm not sure I will get a flicker thing on the film.

Would anybody answer this or tell me any info about the flicker things??



What made you choose 90 degree shutter, instead of say 144? Won't 90 give more
strobing of motion (like in "Saving Private Ryan" ?)
  • 0


rebotnix Technologies

Ritter Battery

Broadcast Solutions Inc

Willys Widgets

CineLab

The Slider

Metropolis Post

Tai Audio

CineTape

Paralinx LLC

Technodolly

Gamma Ray Digital Inc

FJS International, LLC

Media Blackout - Custom Cables and AKS

Opal

Wooden Camera

Aerial Filmworks

Abel Cine

Rig Wheels Passport

Visual Products

Glidecam

Willys Widgets

Visual Products

FJS International, LLC

Wooden Camera

Opal

Tai Audio

Abel Cine

Glidecam

Broadcast Solutions Inc

Rig Wheels Passport

Media Blackout - Custom Cables and AKS

rebotnix Technologies

Paralinx LLC

Metropolis Post

Aerial Filmworks

The Slider

Gamma Ray Digital Inc

Technodolly

CineLab

Ritter Battery

CineTape