
Pro: Adds artfical light. No blurr.
Cons: cause oily shiny spots. Makes your backround very dark. The subject looks flat and plain, because the flash takes away shadow.
Also red eyes.
Flash is not needed when there is a large amount of light already. Also when you are taking pictures of light like chistmas lights, or fire.
In my photo you can see many intresting city lights. If the flash was used this would eliminate the decortive lighting. It would also be bleak and boring. It would probally have a bright fence an really dark backround.

