The current method for fast camera access in iOS 5 might soon be changing into a faster camera access in iOS 5.1, according to Blog do iPhone. The existing method involves double-clicking the Home button and tapping the Camera icon to quickly switch to the Camera app. That's 3 actions and a weight for a separate app to launch or come to the foreground. The new method is a gesture -- a slide up to reveal an embedded camera. That's 1 action and no wait for a separate app. You just side and shoot.
They're only showing pictures of the supposedly new user interface, so it's hard to tell how it feels in implementation. If accurate, Apple would have to give it enough traction and timeout so you can't accidentally reveal the camera in your purse or pocket, and leave it on to drain the battery.
Likewise, since fast camera access bypasses the passcode lock, hopefully Apple will add a Settings toggle to disable it when and if you want to, like for when your prankster friend is visiting and tries to photo bomb you.
iOS 5.1 has been in developer beta for a long while now, with current guestimates pegging its release sometime in March to coincide with the iPad 3 release.
Source: Blog Do iPhone