If your camera will be aiming at a screen projector, then make sure that the room is dark and that the lighting in your room doesn't change much change much. Use the software to turn off the automatic focus features and as long as people don't walk in front of the camera, it should be fine. Though this is possible, it is not the ideal way to show something on facebook that requires people to look at what's being projected. Might I suggest you look into OBS, a free streaming software. With OBS, you should have the ability to stream to FACEBOOK and switch back and forth between the WebCam feed and the presentation, meaning that the people watching on Facebook will see the clearest presentation because it's as if they were there in the same room with you. Depending on how much time you have to learn OBS, you may have to use the Webcam the way you want for now, but try OBS for a future presentation. You will love it.