You’ve probably heard by now that if you want to put the background behind your subject out of focus, you choose a “wide-open” aperture setting like f/4 or f/2.8, but there’s something they’re not telling you. For that to work, you actually have to zoom in somewhat on your subject. So, if you’re using a wide-angle lens (like an 18mm, 24mm, 28mm, and so on), even at f/2.8, unless your subject is really, really physically close to the lens, you’re not going to get that out-of-focus background you’re looking for. So, to get that soft, out-of-focus f/2.8 or f/4 background you’re dreaming of, switch to a telephoto lens, and know that the tighter in you are, the more out of focus the background will appear. So, at 70mm, it’s going to look a little blurry. At 85mm, even more so, as long as you’re fairly tight in on your subject—move back 10 feet from your subject, and you lose it. At 120mm, you’re getting nice and blurry backgrounds when you’re zoomed in, and if you zoom in tight at 200mm.