Depth of field and other photo lessons

Right before moving to Kenya my cousin helped me buy a new camera--a Nikon D40X. It was amazing--the auto setting gave me great photos overall. There were times, though, when I couldn't get the camera in auto setting to give me the picture I wanted. One particular setting that gave me trouble was when I was out on safari, trying to get a picture of a person in the foreground and the animal behind them in the background (you know the shot you want so you can show your friends and say, "look at me! I went on safari!"). On auto the camera seemed to choose one thing or the other to focus on, either the background or the foreground but not both...

I think those are elephants??

I still have so much to learn about photography, but my digital photography class has taught me so far about ISO (film speed), aperture, shutter speed, and I've learned how to change the settings so that I can change the depth of field, which was the problem I was encountering in the above picture/situation. I needed a low aperture to give me a full depth of field (meaning all objects in range of the photo are in focus).

For taking portraits, it's good to have a shallow depth of field in order to allow the focus to fall on the subject. Here's my little model, Dayzney, as she prefers to be called these days. My teacher told us not to use kids because they couldn't hold still enough, but I can't resist this little girl's expressions, so with a little bribery we got some great shots.

Notice how the background is out of focus, allowing you to focus on the subject.

St. Patty's Day Parade

Full Depth of Field

Notice how everything in the picture--from the girl in the left of the photo back through the parade--is in focus.

Shallow Depth of Field

Notice how the little boy and his shamrock hat are in focus, drawing your attention to him, while the rest of the photo is less in focus.