When I try to use Live View on my Canon 50D, for some reason the AF-ON button doesn't focus the image, but the star button in the middle does. I have that star button set as my Back Focus button to match the button layout on my Canon BG-E2N battery grip, which has no AF-ON button. Is this causing the conflict? Just trying to get Live View to operate as described in manual, you tube tutorials, etc. Thanks in advance.
If you have the [*] button reassigned as the [AF-ON] button, it will perform that function in both viewfinder and Live View modes.
The custom menu in the 50D has a single menu item (C.Fn IV:2 - AF-ON/AE lock button switch) for swapping the functions of the [AF-ON] and AE lock [*] buttons.
If you've assigned Autofocus start to the [*] button, then you've also assigned AE lock to the [AF-ON] button.
If you have (C.Fn IV:2 - AF-ON/AE lock button switch) set to enable, when any instructions in the manual, youtube tutorials, etc. say to press the [AF-ON] button you should press the [*] button instead.
Conversely, you should press the [AF-ON] button when manuals or instructional videos tell you to press the [*] button. This would also include, for instance, zooming out when reviewing images.