[davidmanze]

You hold the camera, the nut in your example. The lens weight -> spanner. If the lens is too heavy you don't drop the camera, rather the lens will rotate downward.

 No  ...... This is basic physics terminology BC .... I was taught at school in physics to always use the correct terms to avoid ambiguity ...... 

 ...... a lens rotating downward ?? ...... you know in all my years of reading about photography this is a first for me!! ........ 

  ....... even "after" a heavy session at the pub ......   .......  "when having had the occasion of making love to a nice young lady ....... I've never said .. "sorry darling I can't tonight, I've drunk too much .........   my penis is rotating downwards"    

 I note in my latter years it sometimes does ...  but I've never before phrased it in that fashion ......