There are probably a number of ways to do this, but the easiest I've found is to just use your volume rocker to take the phone down to silent and you'll get no camera noise.
ah there's no way to just turn it off? hmmm i'm not rooted so i can't delete the sound file. don't really want to keep turning off the volume just to take pictures. i just find it annoying when people take pictures in public and there's a sound. i don't want to be that person lol. >_< guess it's not as bad since the camera sound isn't that annoying shutter sound.
BTW, if rooted the shutter sound (although I like the Freudian slip of "shudder sound") can be deleted/renamed (/system/media/audio/ui/camera_click.ogg) but I don't think the focus sound can be.
I've installed Volume Control Plus which has a nice side effect of giving you a different volume setting when you're on Bluetooth or have headphones plugged in. While it's more of a kludge, I'd rather have a dead silent phone unless I've got headphones on most of the time anyway so it works well for me.
Of course, many 3rd party camera apps can disable the sound in their menu settings.
BTW, if rooted the shutter sound (although I like the Freudian slip of "shudder sound") can be deleted/renamed (/system/media/audio/ui/camera_click.ogg) but I don't think the focus sound can be.