I use Rhino to recreate views of photos taken by real cameras. Real cameras have a focal length but also a sensor size which is often not 35mm full frame format. Therefore, they are subject to a crop factor when converting the real focal length to a 35mm equivalent focal length.
How does Rhino’s virtual camera work? I know that I can resize the window by hand (the box to enter the Viewport pixel dimensions is always greyed out for me). The viewport size should mimic the sensor size. I typically set the viewport size to be the same aspect ratio as the photo that I’m working with.
So is the focal length in Rhino a 35 mm equivalent focal length?