The first thing I do when I go out to shoot - or for the first shot - is to turn on the camera and look at the settings. This would include looking at how many shots the camera says I have left on the card. This tells me if there is a card in place or if the camera is not seeing the card - it has happened twice that the camera would not recognize the card for picture taking but for viewing the images contained therein.
It happened once while I was in Honduras. I removed the batteries and let it sit overnight - I took the Optio S4 and LXen for the night - and everything was fine the following morning.
Just some points from this user,
César Panama City, Florida
Bruce Dayton wrote:
Not only is the setting stupid, the default is even stupider. I did that once and found the setting and turn it to not letting me shoot without a card in.
I bet most of us have learned the hard way.