when you move the camera...you have the button below the preview window called "Set Camera" click it and save the scene...
that button gives you an option to explore more angles without losing the default/desired camera angle....but when you render the scene, the renderer will use the camera angle where the last set camera option was used. For example you choose a camera angle and hit the set camera angle and then you make some changes to the camera angle and forget to hit the set camera button, the renderer will automatically use the old fixed camera angle where the set camera button was activated.
you can always write down the camera coordinates and pitch/rotation of camera and then play around for more angles and if you would like to return to old camera angle, you can just plug in the numbers and off you go!....
I hope I made sense....because I am very bad at explaining things...