Are you by chance trying to get a camera angle Looking UP at your subject?

This happened to me all of a sudden, it took me bit then I realized I had the camera BELOW ground.
Working in the work space all looked just fine, but renders came out a Blank Screen.
At first I could not believe this was the case but I moved the camera Up and re-rendered and *POOF* there was my scene....just not at the angle I was wanting so I had to play around until I got an angle Poser would accept and I would accept: