Jump to content


Photo

Circular vs Linear Pola


  • Please log in to reply
4 replies to this topic

#1 Alfeo Dixon

Alfeo Dixon
  • Basic Members
  • PipPipPip
  • 120 posts
  • Camera Operator
  • Atlanta

Posted 26 July 2010 - 07:21 PM

I wanted to explore the usage and differences of using a circular or linear pola filter.

Are there any benefits of one or the other? Applications that may call for either?

I'm well aware that auto focus will not work with linear pola filters, but I am not concerned with auto focus.
  • 0

#2 John Sprung

John Sprung
  • Sustaining Members
  • 4635 posts
  • Other

Posted 26 July 2010 - 08:16 PM

Linear polarization has long been used on cameras to make the sky blue and reduce kicks from shiny objects. Circular polarization is used in some versions of 3D projection to separate the images to your eyes using glasses, but I haven't heard of it being used in shooting. If it is, I'll be interested to see what it does.





-- J.S.
  • 0

#3 William Coss

William Coss
  • Basic Members
  • PipPip
  • 37 posts
  • 1st Assistant Camera

Posted 27 July 2010 - 12:28 AM

Using a linear pola on certain film cameras will conflict with the video tap optics. I always took it as a "grain of salt", almost an "urban myth" of sorts.
Arricam ST, just filling in for the day. Couldn't believe this assistant's filter was even on the truck.

Bill
  • 0

#4 Brian Drysdale

Brian Drysdale
  • Basic Members
  • PipPipPipPip
  • 5070 posts
  • Cinematographer

Posted 27 July 2010 - 02:10 AM

People seem to use the circular on the 3 chip video cameras, although I've used a linear pola on 2/3" cameras without any issues.
  • 0

#5 Frank Kistemann

Frank Kistemann

    New

  • Basic Members
  • Pip
  • 6 posts
  • Electrician
  • Belgium

Posted 27 July 2010 - 05:42 AM

A circular polarizer is essentially nothing else than a linear one with a layer of 1/4 wave retarder plate on it's back (the side facing the lens). Due to that retarder, the plane in which the lightwave is moving, rotates around the wave's axis, so that it would look a bit like a corkscrew. Thus the light could pass through a second polarizer and you won't get any cross-polarization effect, which is important when you work with a system that has another polarizing element like an autofocus or the video assist of some film cameras.



Frank
  • 0


Willys Widgets

Paralinx LLC

CineTape

Media Blackout - Custom Cables and AKS

Wooden Camera

CineLab

Glidecam

Rig Wheels Passport

Abel Cine

Technodolly

Metropolis Post

The Slider

Tai Audio

FJS International, LLC

Gamma Ray Digital Inc

rebotnix Technologies

Broadcast Solutions Inc

Visual Products

Opal

Aerial Filmworks

Ritter Battery

Media Blackout - Custom Cables and AKS

Tai Audio

Gamma Ray Digital Inc

Broadcast Solutions Inc

The Slider

Paralinx LLC

rebotnix Technologies

Wooden Camera

Ritter Battery

Rig Wheels Passport

Metropolis Post

Abel Cine

Aerial Filmworks

Willys Widgets

Opal

Technodolly

FJS International, LLC

Glidecam

Visual Products

CineLab

CineTape