here’s how to constrain the camera to an object…it makes the rendering a lot easier…go into object mode— select the cam, hold shift and selct the object, press control t, select old track, select your camera(only your camera) then press alt r and clear rotation…now when you move ur cam, it’ll stay focused on the object, you can still rotate the cam for a better framing…so there it is ;D
it would be more easy to understand if you had a better structure for the tutorial, just a tip for future tutorials. 
admin.
Rather than rotating the camera later, I usually parent a giant empty to my model and make the camera track that instead of the model. When you move the empty, the camera follows it.
Just an alternative.
What is a giant empty?
Spacebar (or Shft-A) >> Add >> Empty. Scale it to make it Giant.
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I added a cam track empty to my b.blend awhile ago . Now its always there:).
The b.blend stores the default start up scene the cube camera and lamp. On Windows the b.blend is in the Blender program file. To change the b.blend press ctrl u. If you don’t like the way Blender starts after you change it delete the b.blend and restart Blender.
So you just move the camera to where ever, then move the empty to whatever you want the camera to focus on, and you don’t have to mess with the camera rotation? Camera stays upright pointed just where you want it to point? And you can mess with the camera rotation if you want to?
Sweet.
Thanks for starting this thread, i_am_lime.
Just for completeness, there is also a non shortcut way to do this, select the camera, go to Object buttons and add a Track To constraint through Constraints pane.
Hi!
I can’t get this constraint to work. I select the camera. Apply track to constraint and input empty in the target text field. My Empty is placed at center of scene. When I move camera it doesn’t change rotation.
For some reason the track to label text has a red background - seems to signify that something is wrong but I cant figure out what?
I think I got it now. The to: and up: values were both set to ‘Z’ which may be an impossible combination. I now set to: -Z and up: Y. Seems to work perfectly.
So more or less you just saved my life, thank you. I registered especially to tell you so.
I was tracking an object with my camera. Problem was, after a while the object had to move and the camera had to stay still.
So I used an empty, had it follow the same path as the object, and had the camera track it. When the object had to leave the frame, the empty stood still and voilà.