Jump to content


Photo

anomorphic lens to non anomorphic


  • Please log in to reply
16 replies to this topic

#1 Radhika Patel

Radhika Patel

    New

  • Basic Members
  • Pip
  • 4 posts
  • Other
  • london

Posted 26 February 2007 - 12:05 PM

hello

does anone know how to convert anomorphic lens to unanomorphic?

maybe a table to convert or formula?

thanks...
  • 0

#2 Michael Nash

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

Posted 26 February 2007 - 11:14 PM

Anamorphic lenses squeeze the image 2:1 horizontally, so cut the anamorphic focal length in half for the same horizontal angle of view on the Academy aperture. Super 35mm ("full frame") aperture is slightly larger than Academy width, but the 2:1 ratio is close enough to use as a guideline.
  • 0

#3 James Steven Beverly

James Steven Beverly
  • Basic Members
  • PipPipPipPip
  • 4199 posts
  • Director
  • El Paso, Texas

Posted 27 February 2007 - 12:21 AM

hello

does anone know how to convert anomorphic lens to unanomorphic?

maybe a table to convert or formula?

thanks...


Why would you want to convert an anamorphic lens to an "unanamorphic" lens, they already have "unanamorphic" lenses, they're called sphereical lenses. If you're asking what the eqivalent lens of say a 50mm anamorphic in a sphereical lens would be, it's a loaded question, because there is no correct answer. An anamorphic 50mm lens has the same DOF as a sphereical 50mm with about double the horizontal viewing angle so for composition purposes, a 50mm anamorphic would be the equivalent of a 35mm sphereical when the 35mm is projected in 'scope, a 75mm anamorphic would be a 50mm sphereical, and a 100mm anamorphic would be a 75mm sphereical.
  • 0

#4 Max Jacoby

Max Jacoby
  • Sustaining Members
  • 2955 posts
  • Other

Posted 27 February 2007 - 03:24 AM

Eh Captain, I think you got your math slightly wrong there ;)
  • 0

#5 Radhika Patel

Radhika Patel

    New

  • Basic Members
  • Pip
  • 4 posts
  • Other
  • london

Posted 27 February 2007 - 04:07 AM

thanks guys.

i was just curious if it could be done.

:)
  • 0

#6 James Steven Beverly

James Steven Beverly
  • Basic Members
  • PipPipPipPip
  • 4199 posts
  • Director
  • El Paso, Texas

Posted 27 February 2007 - 04:10 AM

Eh Captain, I think you got your math slightly wrong there ;)


Well, it wouldn't be the first time :D Max, you know a Hell of a lot more than I do on this subject. That's what I took from the answers to the question I posed a while back on anamorphics. Maybe you could explain it again so I can get a more accurate understanding and it can help Radhika out as well.
  • 0

#7 Max Jacoby

Max Jacoby
  • Sustaining Members
  • 2955 posts
  • Other

Posted 27 February 2007 - 05:10 AM

Since the anamorphic squeeze works with a a factor of 2, the horizontal angle gets multiplied by 2. So a 50mm anamorphic lens covers the same width as a 25mm spherical lens, while having the vertical angle of a spherical 50mm of course.
  • 0

#8 Radhika Patel

Radhika Patel

    New

  • Basic Members
  • Pip
  • 4 posts
  • Other
  • london

Posted 27 February 2007 - 06:40 AM

Since the anamorphic squeeze works with a a factor of 2, the horizontal angle gets multiplied by 2. So a 50mm anamorphic lens covers the same width as a 25mm spherical lens, while having the vertical angle of a spherical 50mm of course.



thanks mate. great explanation as well some1 was trying to explain it earlier i like urs best! B)
  • 0

#9 Olex Kalynychenko

Olex Kalynychenko
  • Basic Members
  • PipPipPipPip
  • 868 posts
  • Cinematographer
  • Dnepropetrovsk, Ukraine

Posted 27 February 2007 - 12:48 PM

hello

does anone know how to convert anomorphic lens to unanomorphic?

maybe a table to convert or formula?

thanks...


Depend, what type of lens you wish convert.
If we told about zoom lens with rear anamorphic components, you need disconnect of rear anamorphic compoonnet and lens will work like spherical zoom lens ( for example russian 35 OPF-7-1, 35 OPF-15-1, 35OPF-18-1 and other ).

The some prime anamoprphic lenses have anamorphic components inside of body of lens after first focusing comoponents. You need take away of anamorphic components and re-adjust of lens.

But, i not understand of your idea. This is similar, of you take gold bullion and drive nail.
  • 0

#10 James Steven Beverly

James Steven Beverly
  • Basic Members
  • PipPipPipPip
  • 4199 posts
  • Director
  • El Paso, Texas

Posted 02 March 2007 - 05:02 AM

Since the anamorphic squeeze works with a a factor of 2, the horizontal angle gets multiplied by 2. So a 50mm anamorphic lens covers the same width as a 25mm spherical lens, while having the vertical angle of a spherical 50mm of course.


Thanks Max, That makes perfect sense. I had the idea right I just can't divide by 2. The scary part is I went to collage! B)

Edited by James Steven Beverly, 02 March 2007 - 05:05 AM.

  • 0

#11 Max Jacoby

Max Jacoby
  • Sustaining Members
  • 2955 posts
  • Other

Posted 02 March 2007 - 05:15 AM

The scary part is I went to collage! B)

They obviously didn't 'collage' you together properly ;)
  • 0

#12 David Mullen ASC

David Mullen ASC
  • Sustaining Members
  • 19759 posts
  • Cinematographer
  • Los Angeles

Posted 02 March 2007 - 11:11 AM

Since the aspect ratio is different than 1.85, the notion of an "equivalent" spherical lens is a bit vague unless you are shooting Super-35 for cropping to 2.35.

Yes, a 40mm anamorphic "sees" horizontally the same as a 20mm spherical, but that doesn't mean you reach for a 40mm anamorphic when you'd normally reach for a 20mm spherical when shooting a 1.85 movie. Since the vertical view is still smaller, a 40mm spherical view whether anamorphic or spherical, what lenses you tend to use are not quite twice as long in anamorphic -- hence why you may be using a 75mm anamorphic to shoot an over-the-shoulder that you normally would use a 50mm for in spherical 1.85. A lot of this is just what feels long or wide-angle to you when lining up a shot.

With Super-35 cropped to 2.35, you'd expect to be picking lenses closer to half the focal length of what you'd use in anamorphic (taking into account the wider gate of Super-35), although your eyes can get fooled by seeing "outside" the 2.35 framelines in the viewfinder, which is one reason Super-35 movies can look over-cropped sometimes as you may have a tendency to pick a lens and frame a shot with this outside area affecting your thinking.
  • 0

#13 James Steven Beverly

James Steven Beverly
  • Basic Members
  • PipPipPipPip
  • 4199 posts
  • Director
  • El Paso, Texas

Posted 03 March 2007 - 02:50 AM

Thanks for the input, David. I THOUGHT that's what I had gotten from the previous disscussion on anamorphics but I felt I had to bow to Max's greater expirence in the matter. I guess I should have had more confidence in my comprehension of the pricipals. Anyway thanks again.
  • 0

#14 David Mullen ASC

David Mullen ASC
  • Sustaining Members
  • 19759 posts
  • Cinematographer
  • Los Angeles

Posted 03 March 2007 - 03:04 AM

Thanks for the input, David. I THOUGHT that's what I had gotten from the previous disscussion on anamorphics but I felt I had to bow to Max's greater expirence in the matter. I guess I should have had more confidence in my comprehension of the pricipals. Anyway thanks again.


Max is right, of course -- it is a simple matter of getting 2X the horizontal view compared to a spherical lens of the same focal length. It's just that the aspect ratio affects what focal lengths you tend to choose.
  • 0

#15 James Steven Beverly

James Steven Beverly
  • Basic Members
  • PipPipPipPip
  • 4199 posts
  • Director
  • El Paso, Texas

Posted 03 March 2007 - 03:28 AM

Max is right, of course -- it is a simple matter of getting 2X the horizontal view compared to a spherical lens of the same focal length. It's just that the aspect ratio affects what focal lengths you tend to choose.

I see, so the choise is more a matter of astetic preference than formulaic constansts. your own personal style or the needs of the scene dictate whether you would use a 50mm anamorphic in the same way you would use a 35mm sphereical or the same way you would use a 25mm sphereical. A 50mm would be eqilalent to both in horizontal composition but the staging and placement of the camera may vary depending on whether you want to aproximate the field of view of a 25mm sphereical or a 35mm sphereical. Did I get that right? :huh:
  • 0

#16 Leo Anthony Vale

Leo Anthony Vale
  • Basic Members
  • PipPipPipPip
  • 2010 posts
  • Other
  • Pittsburgh PA

Posted 03 March 2007 - 01:27 PM

Yes, a 40mm anamorphic "sees" horizontally the same as a 20mm spherical, but that doesn't mean you reach for a 40mm anamorphic when you'd normally reach for a 20mm spherical when shooting a 1.85 movie. Since the vertical view is still smaller, a 40mm spherical view whether anamorphic or spherical, what lenses you tend to use are not quite twice as long in anamorphic -- hence why you may be using a 75mm anamorphic to shoot an over-the-shoulder that you normally would use a 50mm for in spherical 1.85. A lot of this is just what feels long or wide-angle to you when lining up a shot.


John Alonzo at an AFI seminar on "Chinatown" said that he and Polanski considered a 40mm scope, which most of the film was shot with, was equivalent to a 25mm in 1.85/1.

Which it is when comparing it vertically. 1.85 is still technically widescreen, so a vertical conversion with a factor of 1.6x seems like a practical conversion.
  • 0

#17 Max Jacoby

Max Jacoby
  • Sustaining Members
  • 2955 posts
  • Other

Posted 03 March 2007 - 02:42 PM

When comparing different formats, one needs to decide on which angles (horizontal or vertical) one wants to compare.

Since the vertical angle stays the same in most cinemas (i.e. a scope film gets projected wider than 1.85, not cropped), it makes sense to pick it over the horizontal one.

A 50mm anamorphic lens has the same vertical angle than a 32mm in 1.85 and a 28mm in Super 35 for instance.

If you chose to go with the horizontal angle on the other hand, the equivalents of a 50mm anamorphic lens are a 25mm in 1.85 and still a 28mm in Super 35mm.

Obviously these are just the numbers, as factors like distortion also have an influence on the lens one choses.
  • 0


Aerial Filmworks

FJS International, LLC

Visual Products

The Slider

Rig Wheels Passport

Wooden Camera

Metropolis Post

Broadcast Solutions Inc

CineTape

Technodolly

Opal

Media Blackout - Custom Cables and AKS

Willys Widgets

Ritter Battery

Abel Cine

Tai Audio

rebotnix Technologies

CineLab

Gamma Ray Digital Inc

Paralinx LLC

Glidecam

Opal

Technodolly

Gamma Ray Digital Inc

Rig Wheels Passport

FJS International, LLC

Paralinx LLC

CineTape

Media Blackout - Custom Cables and AKS

Glidecam

Abel Cine

Tai Audio

Wooden Camera

Ritter Battery

Broadcast Solutions Inc

The Slider

CineLab

Aerial Filmworks

Willys Widgets

Visual Products

Metropolis Post

rebotnix Technologies