This is hard to explain so I'll use sequential screen shots. For simplicity, I'm using the Appearance Model supplied with Visualize (standard version). When I create a new camera (see sc1.jpg), there is a camera inserted into the viewport. Notice I have "show in viewport" checked at bottom. Also notice that the numbers filling the fields under camera positioning are 7.10, 19.30, 0.00. The next image (sc2.jpg) shows the same model, but with different camera position numbers. The camera and its position move from one image to the next as you'd expect with different camera position coordinates. If there is only one camera in the scene, why am I seeing it in the image instead of seeing through it (or through the virtual viewfinder)?????
I am not sure of the correct procedure to turn these cameras off. In sc3.jpg, the "share in viewport" is not checked, but the camera is still visible. I was able to get the camera to go away by opening another camera, then unselecting "show in viewport" under Camera positioning, and then opening the desired camera back up (see sc5.jpg). I haven't a clue as to what's going on with the interface here.
Lastly, when I click on multiple cameras in the camera palette, they are sequentially added to the scene, but I can only delete them and can't figure out how to turn them off or remove them from the image. Deleting them from the project is the only thing that seems to work.