I assigned the AE-L, AF-L button to activate focusing on my Nikon D5500, but I can still focus using the shutter button.
I would like to know if it was possible to use the AE-L/AF-L button to set focus only and the shutter button to take photos only.
According to page 267 of the D5500 Reference Manual, using custom setting f2 to set the AE-L/AF-L button to AF-ON prevents the shutter release button from focusing.
Did you put the camera in Continuous mode? I understand back button trick will not work if it isn't in Continuous mode.
I think I know what happens. If you have set ae-l af-l af af-on and press the button to focus it will focus the lens and the focus confirmation dot will light up in the viewfinder.now if you press the shutter button with the lens still in focus( from pressing ae-l af-l) the focus confirmation dot will light up again :it does not mean that pressing the shutter button activated focus, just that focus had been acquired. To test easily try to focus on a object at a different distance with the shutter button first: it will not focus and you will not see the focus confirmation dot in the viewfinder
Beside AF-ON button you need to release shutter from autofocus. Check this manual how to do it:
The setting in question is found on the Timers/AE Lock submenu of the Custom Setting menu and is called Shutter-Release Button AE-L, as shown in Figure 10-21. If you set the option to On, your half-press of the shutter button locks both focus and exposure. This option affects movie recording as well as still photography.
