Hi Daisy!
I love your enthusiasm. Let's see if I can come up with some tips for you ....
With regard to shutter speed: Faster shutter speeds allow you to "freeze" action. Slower shutter speeds allow you to "blur" action.
With regard to aperture (F-Stop): The smaller the aperture, the greater the depth of field. That is, the greater will be your range of focus in front of and behind the object you focused on. The larger the aperture, the shorter the depth of field allowing for you to isolate a particular portion of the subject in the frame. These ranges are dependent, also, on the distance the camera is from the subject. In other words, the closer you are to the subject and the larger the aperture, the more you will find the depth of field shortened.
Which combinations to use: Well, this is entirely dependent on the degree of light hitting and surrounding your subject as well as the ISO (ASA) value you are using. Here's where the real fun comes into play! I'd only shift one setting at a time while I play with the strobes.
To understand what your camera is doing with regard to aperture, I'd recommend you stage a couple different types of shots. Pose your subject standing next to a fence row. The subject should be in the middle of your frame and the fence should run at a slight angle to you. Use a tripod if you can. Set your camera to aperture mode and shoot the subject varying the aperture with each shot. Keep your focal plane the same (that is, always focus on the same spot from the same distance). Since your subject is not moving, your shutter speed will shift automatically for you. You'll be able to see your depth of view change with each change in aperture. You may want to activate your flash so that you don't underexpose your shots as you vary the aperture. Fun!
Now, for the second series, set your aperture to its largest setting (F1.4, or whatever is your largest). Place your subject next to a fence row again like before. Now take a shot. For each successive shot keep your aperture the same but move a foot closer to your subject. Notice the shift in depth of view? Neat, huh!
These exercises will help you understand your camera settings and depth of view. Depth of view is important in portraiture and macro work. The better you understand your camera, the more control you will have over the finished product.
As for shutter speed, your flash system may allow for various settings. Keep in mind that the faster the shutter speed (with flash work), the less ambient light you will be letting in to your camera. If you want to pop your subject out of the background naturally (without using dark backdrops, etc.), you can do so by using a fast shutter speed. Shadows will be harsher. Alternately, if you want to include the details surrounding your subject, then use a slower shutter speed. This allows more ambient light in to your camera.
Whew! I think that's about all I can think of off the top of my head. Hope this helps! Let us know how things go with your new joy!
