[feature] Redo camera section

[Derpius]

Is your feature request related to a problem? Please describe.
The current camera section uses a pinhole ray gen derived by converting the focal length and sensor height to field of view, then plugging that into an FoV based pinhole camera ray gen equation which leads to overcomplication

Describe the solution you'd like
Instead use a more intuitive equation by computing scale factors from the sensor height only, and setting the distance to focal length