The simple way to setup an Anamorphic lens is to
- Select the camera you will be using
- Go into its optical properties and create a new Frame Size with the width of the film/sensor multiplied by the squeeze factor of the lens. Thus is it is turning 4:3 into 2.39:1 you do the following:
- Convert any aspect ratios like 4:3 into a single number, in this case 1.3333.
- Divide the effective aspect ratio gotten by the camera with this lens (in this case 2.39) by the original aspect ratio, in this case 1.333
- The squeeze factor would thus be 2.39 / 1.33 which comes out to 1.79699
- Take the camera's current film/sensor width and multiply it by that number and enter it and the final aspect ratio in the definition of the film /frame size
- Use that newly created Film/Frame Size and you will see the final unsqueezed results at any given focal length
For more details why this works, read this: FrameForge-Anamorphic-Lenses.pdf
See the Related articles if you need more details on how you would go about this process.