Lesson #1 to taking a picture of a child. Get down low. Be on their level don’t take pictures of the tops of their head.
Lesson #2 is to focus on the eyes. This is true of almost any portrait. Focus on the eyes. When we talk to people, look at people, it is the eyes that engage us. In a picture we can’t use our voice to speak, so it is our face that does our talking, and most especially the eyes.
I took this picture in shadow, without flash or any artificial lighting. Shadow is often better than direct sunlight for portraits if you don’t want to use a flash. When the subject is in complete shadow you don’t have to worry about having dark shadowed circles where the eyes would be or on the side of the nose. There are not the extremes of contrast. It is often a nice even lighting, with subtle hints of shadow upon the face. There are times where harsh shadows can make a face more interesting, but that is more often the exception than the rule.
Try to have the brightest part of the sky, or whatever is lighting the scene behind you and your camera. This way it can be reflected in your subjects eyes, giving them that extra little spark of life. It also means that your subject won’t be silhouetted, and will have the best color tones in their face. This picture was taken at the beach. The light in the eyes is the last light of the day, and is at my back. In front of me was cliffs. If I had taken the picture from the other side of the child, the picture would have been a silhouette- suitable for a landscape with a person in it, but not a portrait.
This picture was taken with a fairly long focal length- 420mm. This gave me a shallower depth of field, even though my aperture was at 5.7 (meaning that even though the eyes are in focus, the ears are out of focus). Such a long lens also meant that there would be little distortion from the lens (some of the wider angle lenses can change the shape of a face). An alternative to this long of a lens is a shorter lens while still maintaining the shallow depth of field, is to open aperture wider (meaning a smaller aperture number such as 2.8 or 1.2). I usually will not go shorter than a 50mm lens on portraits however, unless I am trying to elongate or distort some part of the body, such as the legs or arms.
I also prefer long lenses when photographing children, because it allows me to be farther away, not so much in their face, which I feel often allows them to relax more. Adults on the other hand, if you point a really big lens at them become more nervous (unless you are far enough away that they don’t really notice you.)