@dmilligan
Understood and not a priority.
I have already solved it by explicitly tracking and checking aperture, focus distance and focal length.
My use is in my focus bar script, as unless the above 'properties' change, there is no point updating the focus bar, i.e. wasted Lua cpu action.
Until I did the above, my script constantly was updating, i.e. every time my shoot_task event ran.
I just thought the property approach would be 'better'.
Thanks for the education.
Cheers
Garry