Rhino lens length and aspect ratio

I understand that Rhino creates the field of view of a full frame 35mm sensor for any given lens length. The outcome of this is predictable when the size of a viewport or detail matches full frame 35mm proportions.

But I’d like to know how rhino manages the field of view when the aspect ratio of a view size varies from full frame sensor proportions. In the example of a 2.35:1, does Rhino 1) preserve the width, cropping from the top and bottom; 2) preserve the height, adding to the sides; or does it make some other adjustment?

Finally, does the behaviour vary depending on whether a lens length is changed in a fixed proportion view vs when the proportion of a view is changed? I believe that Rhino always changes camera position to ensure the same elements are visible when a view’s proportions are changed, even when a detail view is locked. This seems to suggest Rhino’s either cropping or adding in different axes depending on this requirement.

Working in film production i’d like to be clear on this.

I think it fits the largest “correct” FOV it can into the viewport, and then extends as needed to fill the viewport dimensions. Very slender viewports (either tall or wide) will have distortion on the ends.

There may be some useful info here posted a while ago by @SamPage:
Lens Questions [McNeel Wiki]

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Rhino will always have a minimum film gate of 24mm, and the major dimension will 24mm * Viewport aspect ratio. This means whenever you drag around a viewport boarder changing the aspect ratio, you’re effectively changing lens length when trying to simulate a motion picture camera.

There is the script that is attached to the wiki article suggested which will work, but it should be noted that it’s old (missing more modern cameras), it doesn’t update the lens when you change the viewport aspect, and will only work on the Windows side,

There is a more robust plugin by David Moreau which can be found in the Package Manager which is called Cephalopod, but as far as I know is also Windows only.

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Thanks. I googled <david moreau cephalopod “package manager”> with no results.

Oh I see. Package Manager: a command and place where plugins are listed.