Ever since I have been filming with my iPhone 3Gs, I always wanted to be able to lock exposure and whitebalance...
Imagine the following: You are filming your kids in the living room, you're trying to keep track of your kids playing around. Suddenly they're moving in front of a brightly lit window. The auto-exposures "sees" the bright light coming from the window and the exposure is changed dramatically. Inside the house, because of these backlit sceneries, most of the time your footage is temporarily way underexposed ;-(
So this is caused by backlight coming in through the windows. Most of the time right behind your main subject. While just seconds before you started the recording, they were playing in front of a solid wall. The recording started with a correctly exposed scene, but as things started to move towards the window, your movie in fact looks like rubbish.
Typical indoor underexposed scene
Then you really wished you could switch that auto-exposure thingy off and although you would blow completely
out the exterior scene in the window, you wouldn't care because you would still be able to see the expressions on your kids faces.
So here is the good news: Now you can! With CamLock.
Nothing annoys me more then a whitebalance that keeps going from cold to warm to cold again. This can happen and is sometimes so visible it really kills the footage. With CamLock you can lock at any given whitebalance that suits you best and the cam will stick with that whitebalance for as long as you think it should. Even if the whitebalance you chose turns out to be wrong it's easier to fix during post processing when it's not dynamically changing all the time.
Last is focus, although the default cam app is not continuously focussing while filming and you are able to control where it focusses quite well (though focus and exposure are coupled which sometimes is a pain in the a**), it can still be a nice feature to let somebody walk into focus while you're camera's focus is locked to closest distance. In that way you could still have some narrow depth of field effects even though the cam sensor really is to small and the depth of field almost infinite.
People like me, who think they can do a better job setting the right exposure and whitebalance, for known problematic situations, for example while you're:
Incorrectly exposed and whitebalance way off (to cold), scene in the snow
Correctly exposed scene in the snow
Take a look at the examples page to see what can be accomplished