It used to be that I was able to use the lock switch on my iPhone to mute all alerts and sounds (with the exception of any music, video, etc.); and this included the camera's shutter noise. Then when I went to set the switch to the un-mute setting, I could get the camera's shutter noise back.
This was especially useful when I needed to inconspicuously take photographs.
It seems now, though—perhaps even as early as iOS 5.1, I can't recall—the camera noise goes off each time I take a photo, regardless of other mute settings.
And I've already toggling the Settings » Change with Buttons setting, it has no effect.
Is there some sort of hidden option I've lost track of to let me regain this functionality?