Depth of Field
The field of focus in a scene. The key here is understanding that this depth is adjustable. So more or less of your subject can be in focus.
Normally think of really small objects photographed with a small DOF and medium to large objects as having a larger DOF. This is good to keep in mind when rendering your image. DOF can be adjusted with the camera or if you don’t want to wait, you can often fake it in post production.
Smaller numbers = more dramatic angles. The basic rule here is, the larger the object you’re rendering, the more dramatic you can make it look by reducing the lens length down. Smaller objects work better with a higher lens length. If you’re looking for the isometric look, a super high number can be put in, to make things look parallel. If you are rendering right out of your viewport, often you can set the view to “parallel” and this will make it a true isometric view.
Vignetting is the lessening of brightness around the edges of your render that create a little more mood to your renderings.
Special thanks to Daniele Pesaresi for his use of the Tilt-shift photo!