nostr:npub1fy3lzlkjyfu2rk6adwg066tpagqhd0sl6mznhgtj523p4cggeqksrzm7wg seems to work fine for me. Obscura lets you change the behaviour of the volume buttons, so double check that Volume Up is set to capture photo. 

(Also behave of the workarounds to get this to work at all, it might not work if your volume is set to 100%)

((We were supposed to get a proper API for this with iOS 17, but there’s been no further details about that))