If you downloaded Sensei Format 3 before September 4, 2013 then you may encounter a glitch when using the depth of field. If you downloaded it after September 4 then there shouldn’t be a problem. To fix this you don’t need to download SF3 again, just turn on Blender hover your mouse over the bottom right hand portion of the screen where it says “Use Nodes” and hit the tilde key on your keyboard (top left corner of the keyboard) to maximize the window. In the top menu bar of the window make sure that “Use Nodes” “Free Unused Nodes” and “Backdrop” are all unchecked and that Autorender is checked and that the thumbtack icon next to autorender is also pressed down. Hit the tilde key to get out of that screen.
The place where it normally says “Use Nodes” in the bottom right hand side of the screen, might looked messed up now. Just hold down your middle mouse button over that area and drag your mouse to the left to pull the menu back to its previous position where you can see the “Use Nodes” checkmark box again like it was. Leave it unchecked for now until you want to use depth of field later. Then go to File in the top left hand side of the screen and select “Save Startup File” and everything should be fine.