Jump to content


Photo

Do video lenses behave differently from Film Lenses?


  • Please log in to reply
5 replies to this topic

#1 Bob Hayes

Bob Hayes
  • Basic Members
  • PipPipPipPip
  • 1087 posts
  • Cinematographer
  • Culver City, California

Posted 20 March 2008 - 05:53 PM

I have a strange question. Some one told me that if I put a video lens on a film camera the colors will not all focus on the film plane because they are staggered to fall onto different chips. I thought the prism did all the separating and I also thought a lens was a lens. Granted some lenses have better quality and some are designed to hit a smaller target. I had never heard that video lenses behaved this way until recently.
  • 0

#2 Michael Nash

Michael Nash
  • Sustaining Members
  • 3330 posts
  • Cinematographer
  • Pasadena, CA

Posted 20 March 2008 - 06:13 PM

It's true. The prism does do the separating, but focuses each color at slightly different distances. 2/3" video lenses are calibrated for these distances, not a single focal plane.

There's an adapter that corrects for this, which is what allows single-sensor cameras like the RED to use 2/3" video lenses.

http://pro35.com/zgc...5256EC9005F5789
  • 0

#3 Mitch Gross

Mitch Gross
  • Basic Members
  • PipPipPipPip
  • 2873 posts
  • Cinematographer

Posted 20 March 2008 - 08:39 PM

It's true. The prism does do the separating, but focuses each color at slightly different distances. 2/3" video lenses are calibrated for these distances, not a single focal plane.

There's an adapter that corrects for this, which is what allows single-sensor cameras like the RED to use 2/3" video lenses.

http://pro35.com/zgc...5256EC9005F5789

Yes that's the Abekas device. They make one for Super-16 that corrects back for the color wavelengths and another for 35mm that does the same but also incorporates a doubler (2x magnifier) to cover the image area (and eat two stops of light).

Abel has the S-16 unit in rental, which can also be used on a RED shooting in 2K mode.
  • 0

#4 Evangelos Achillopoulos

Evangelos Achillopoulos
  • Basic Members
  • PipPipPip
  • 102 posts
  • Digital Image Technician

Posted 21 March 2008 - 05:03 PM

Where can I find more info about that ?difference? that 2/3 prism lens has?

How much different they are or what is the result in use of flat photo lenses in prism based cameras?

Do they introduce aberrations and what kind?
  • 0

#5 Michael Nash

Michael Nash
  • Sustaining Members
  • 3330 posts
  • Cinematographer
  • Pasadena, CA

Posted 21 March 2008 - 05:30 PM

Where can I find more info about that ?difference? that 2/3 prism lens has?

How much different they are or what is the result in use of flat photo lenses in prism based cameras?

Do they introduce aberrations and what kind?


On a technical level, I don't know; wish I could help you.

But on a practical level, you can't combine the different lens/camera formats without an adapter anyway, so you might as well use the right one...

http://www.smsprod.c...angenieux4.html
  • 0

#6 Mitch Gross

Mitch Gross
  • Basic Members
  • PipPipPipPip
  • 2873 posts
  • Cinematographer

Posted 24 March 2008 - 10:25 AM

Search the archives of this forum (cinematography.com), as well as cinematography.net and wikipedia.
  • 0


Rig Wheels Passport

The Slider

Abel Cine

New Pro Video - New and Used Equipment

Metropolis Post

Gamma Ray Digital Inc

FJS International, LLC

Broadcast Solutions Inc

Ritter Battery

rebotnix Technologies

Aerial Filmworks

CineLab

Media Blackout - Custom Cables and AKS

Technodolly

Visual Products

Tai Audio

Willys Widgets

Glidecam

CineTape

Wooden Camera

Paralinx LLC

Technodolly

Aerial Filmworks

CineLab

Wooden Camera

Tai Audio

Paralinx LLC

Glidecam

Media Blackout - Custom Cables and AKS

Metropolis Post

CineTape

Ritter Battery

Willys Widgets

New Pro Video - New and Used Equipment

Visual Products

Rig Wheels Passport

FJS International, LLC

The Slider

Broadcast Solutions Inc

rebotnix Technologies

Abel Cine

Gamma Ray Digital Inc