Quote Originally Posted by Amir Aziz View Post
Advance the shutter then use your finger to flick the shutter button (very fast and light) and the mirror locks up (MLU).

This also works on Spotmatics, the KX and ESII.
I tried this and for a while I was just firing a shutter, but after a while I managed to do it. The best way I can describe it is as if your finger is coming into land on the shutter button, hits the button hard for a fraction of a second and comes back up instantly...