I think a single 'long' press for zoom would have been a better way. By long I'd say 300ms or so. Then a short tap could act the moment you lifted your finger,

I think a single 'long' press for zoom would have been a better way. By long I'd say 300ms or so. Then a short tap could act the moment you lifted your finger, assuming it was below the long tap threshold. iOS uses a long tap to select text though.