Contrôle de filtre neutre ?
The
neutral density filter is a
filtre neutre. This switch must control the filter (probably just on/off).
Since it says "switch" and not "button," I imagine a control that slides back and forth between two or more positions (rather than something that you depress). For example, there is a multi-position switch shown in
this photo (in the red box)... and there are five buttons down the left side of the camera body.
Here is another type of switch, on the lens. I've suggested
contrôle, but I'm not quite sure what the best word is in French.
See if anyone else has a better suggestion....
