Mounting a heavy lens on a camera may cause damage
If not supported properly, a long, heavy lens mounted to a camera may damage the printed circuit board of the camera.
In a typical production setting, the camera can be attached to a custom fixture or tripod. However, if you mount a lens directly to the camera, and the lens is heavier than camera itself, the weight of the lens may cause it to "hang" from the camera, exerting pressure on the printed circuit board and causing damage to parts. This damage, in turn, can cause the camera to malfunction.
In general, we recommend using heavier components as mounting points. So, when using a lens with a camera that is heavier than the camera itself, mount the lens, rather than the camera. Then, attach the camera to the mounted lens so that the camera "hangs" from the lens, rather than vice versa. For lens mounting instructions, consult the documentation for your lens.