When taking landscape photographs and discussing aperture, there's an old expression that comes to mind, 'F8, and be there'. Being Australian, we've put our version, which is, 'F8 is your mate'. F8 gives us that nice in between aperture, it's not too shallow, or the number's not to small, the lens isn't too wide, that we're not getting that blurry background.
Everyone seems to assume that if we don't want the blurry background, take our aperture up as far as it can go, F22 or F32, and make it nice and tight. The problem with that is that we get something called diffraction, that is when all these blades in the lens close as the aperture closes. Light starts diffracting, or seeping through the cracks, and we start getting a softer image, it's not as sharp. With aperture of 8 you'll notice that even though my focal point is at the front of a photograph, I'm still getting detail all the way in at the back. So F8 and be there, and it's still going to be your mate.