The depth of field in your photography can have a dramatic effect on your subjects. A focus distance of four feet or more with the iPhone 3GS/4 means everything to the horizon will be in focus. But a focus distance of 4 to 18 inches can bring some compositional magic to your photos.

Depth of Field Distance Values
Focus Distance to Subject (inches) Near Focus Point (inches) Far Focus Point (inches)
4 3.5 4.5
8 6.5 10
12 9 18
18 12 34
48 and greater 19