Nikon announced yesterday version 4.0 firmware for the Z9.
One of the additional features is Auto Capture. I've just been playing around with this and it could well be a brilliant underwater tool for those shy critters. Garden Eels especially!
Auto Capture allows you set the Z9 up in such a way that if a user-determined sized subject comes into a user-determined sized area from a user-defined direction, the camera will fire a user-defined number of frames; and continue to do so if that was user-defined!
Yep, there's a lot of user-defined in there. The point is though that this feature is incredibly versatile: distance to subject, size, speed, and direction of subject, burst length, repeatability. So set up the user-defineds, plant the camera and swim away and let the Z9 do the rest. Pop to the surface, have a coffee, then go back and collect the camera......
From my initial efforts, all the user-defined should be changeable with the usual housing controls (not that I have a Z9 housing!).
On the face of it, an amazing additional tool..... if you have a Z9. And the housing.