I have a Nikon D750 on which I have setup focusing to be on the AE-L/AF-L button (not on the standard shutter release button). Works fine. Now when using a remote (in my case the Pluto trigger), leaving the camera and lens on AF, I am unable to focus. The Pluto trigger app even has a dedicated "Focus" shutter release mode that is supposed to focus, then shoot, but it doesn't work. Any idea?
The Pluto trigger sends the "Focus" command as a shutter button half press command, rather than a command to "Focus." This is because the connection of the receiver to the camera is via the camera's wired remote port.
That's also what wired remote release cables do. The commands sent by the remote are actually commands for "Shutter button half press" and "Shutter button full press" rather than commands for "Focus" and "Release shutter."