There are several ways of setting up depth of field in the scanline renderer in 3d Studio Max. On the one hand, you could use a similar method as we used in the mental ray renderer version. You'll create a camera using the Ctrl + C method or by creating one manually, and under the “Multi-Pass Effect” group you'll enable the “Depth of Field” effect. When you render, however, you'll notice that it uses a very primitive method for creating depth of field, and this is generally not recommended.