Maya - Lighting and Rendering - Depth of Field

Depth of Field works in Maya through Arnold to blur out the foreground midground or background to create the desired depth of field, resembling a real world camera. In the Arnold settings of Arnold you are able to change many things like focus distance, aperture size and aperture aspect ratio. 

Through the Arnold tab in the camera you can also add effects like vignette. The depth of field in Arnold works effectively however it has a long render time and you also have to render without the added blur before hand and composite the two together if you want to change between the two. 

Depth of Field Final Render