Depth of Field (DOF)

Alright, so it's been a very long time, but I've finally researched it and I will now explain depth of field.
What it means is the distance between the furthest and nearest object. Your camera can really only focus on one thing at a time and the unsharpness decreases gradually on either side of the object in focus.
Depending on the picture you aiming for, you may want the entire picture to be entirely sharp or only a certain object or area to be focused, making the background and foreground extremely blurry.

Again, this picture is from Wiki, not mine, but it explains visually what I just wrote up there. As you can see, everything before and after the middle butterfly is blurry, while the middle one is sharp.
The photo below shows again what I explained.

This picture is taken at f/32 and the flower isn't the main point of concentration.

While this pictture is taken at f/5.6 and the flower is the main attraction.

Thanks for reading, any questions, email or just reply.

OR: http://en.wikipedia.org/wiki/Depth_of_field