The ability to adjust camera lens angle or field of view after installation will depend on the type of camera and the mounting position. Fixed lens cameras cannot be adjusted once installed, while some cameras with motorized zoom lenses can be remotely adjusted to change the field of view. Dome cameras, which are often installed on ceilings, typically have an adjustable lens that can be tilted and panned to adjust the viewing angle.
In some cases, it may be possible to change the lens of the camera to adjust the field of view. However, this requires a compatible lens and knowledge of camera lens installation, which should be performed by a professional. It is always recommended to plan and choose the appropriate lens before installation to ensure that the camera covers the desired area.