Lens & Scopes

Camera
Focal ratio (lens) = Focal length (lens) / Aperture (lens)
Crop Factor x Focal length (actual) = Focal length (equivalent / apparent)
Crop Factor = FoV (Actual) / FoV (Apparent)


Scope
Focal Ratio (Objective) = Focal length (Objective) / Diameter (Objective)
Magnification = Focal length (Objective) / Focal length (EP)
FoV (Scope) = FoV(EP) / Magnification