When using an ArcGIS Pro scene, it does not appear to be possible to get or set the Field Of View property using Python (arcpy.mp). The Camera properties do not include access to the FOV property:
Is there another way to get or set the FOV property using Python?
Would the CIM be able to update what you’re looking for?
Thanks for the tip @CodyScott. The only FOV setting in CIM Map was for animation keyframes, but I have found the relevant property in the CIMDocument part of the spec, under CIMMapView:
fieldOfView - double - The scene's field-of-view in degrees (value must be between 35 and 70). Only used when the scene is in Perspective draw mode.
However I have not been able to access this property through arcpy, as both the ArcGISProject and MapView classes do not have a GetDefinition method. It looks like you can only access the CIM for Map, Layer, Table, and Layout through arcpy.