Sometimes my motorola milestone camera goes crazy and starts out to take photos half dark.
I noticed that it only happens when flash is on. Also, I've seem this happening when the battery is low (~20%), or the system is slow.
As an example, this is a photo I took minutes ago: http://twitpic.com/2q65bs
Update: definitely it is related to low battery, I tried a couple of more tests and if the battery is < 20% this always happens.