Depth of Field

Short Depth of Field 

Walker Evans 

This photo by Walker Evans utilizes a short depth of field, the two people sitting are the main focus and the background behind them is blurred and out of focus.  This is effective in conveying movement as it seems they are on a train or subway.  Without the focus on the two people and not the background the picture would read very flat and would not tell the moving story that it does. 

Long Depth of Field

Walker Evans 

This photo also taken by Walker Evans uses a long depth of view.  All three of the people and the environment around them are all in equal focus.  This helps the photo tell a story about the three men.  If the Barber shop sign was out of focus in the background or the building blurred out the men would be out of context and it would take away from the composition of the photo.