"Camera, picture", you say it and he's ready

Camden is far from camera shy. If he sees a camera, or hears the word "camera" or "picture" or anything along those lines, he says "Cheese". Unfortunately we don't get many kandid smiles from him anymore because he is saying "cheese" everytime and giving a fake smile. We'll take what we can get. There have been a couple of times that someone is talking about a picture or camera, even when one is not present, and Camden pauses whatever he is doing and turns around and says "cheese" looking for the camera. He's got a lot of great expressions lately that I hope to somehow catch on camera, but I'll haven't figured out yet how to

sneak up and take the picture before he sees the camera and says cheese.