Angle between sun, observer with vertex at center

I am a photographer and it would be useful to me if I could calculate the angel that the sun will be shining from when I shoot at an object. The center could mark the subject, but there needs to be a way to add another marker to represent the observer. The vertex would be the center with a line drawn to the observer and another to the sun. The angle could also be broken down to into constituent parts of azimuth and elevation.