The number one flash mistake is taking pictures beyond the flash’s range. Why
is this a mistake? Because pictures taken beyond the maximum flash range will be
too dark. For many cameras, the maximum flash range is less than fifteen
feet—about five steps away.

What is your camera’s flash range? Look it up in your camera manual. Can’t find it?
Then don’t take a chance. Position yourself so subjects are no farther than ten feet
away.