Quote Originally Posted by David A. Goldfarb View Post
The laser pointer and penny tests don't really tell you if the vibration is affecting the image. There could be a lot of vibration when the mirror returns and the shutter closes, and that wouldn't make any difference.
In my understanding, however, the laser pointer test involves actually photographing the laser point on the wall, not just viewing it with your eyes. Therefore, the test should work just fine to tell you if the slap is affecting the camera during exposure.

As for the penny test, it is just silly, IMO.