Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See page_maxonapi_getting_started_foundations_cinema_parameters.
Parameter: Lens Profile Filename
PH_LENS_PROFILE_FILENAME
Parameter: Image Scale
PH_IMAGE_VIEW_SCALE
Parameter: Image Offset X
PH_IMAGE_VIEW_OFFSET_X
Parameter: Image Offset Y
PH_IMAGE_VIEW_OFFSET_Y