Depth of Field - photos fly by

Hello,

i've searched before i posted, but i couldn't find any answer for my purpose, so please do not berate me for posting this:

for a dvd menue i want to animate a number of fotos flying in from the right and out to the left. While they fly in and out they rotate (3d Objects) on the x-axis. Now i turned on Depth of field for the camera, because i want to achieve the effect that while the Photos are not parallel to the camera plane (facing the camera) they blur... But regardless ho much i crank up the aperture and the blur - they don't blur.

I hope that i made my problem clear and i thank anyone, who can set me on the right path...

Cheers Oskar