In article <31656174.B2B@pacific.net>, brooke@pacific.net says...

>I put a Hass. 500C on a tripod and made a few exposures allowing the >mirror to slap, and some where I locked the mirror.
>The ON tripod shots with the mirror slaping showed bluring!
>You can imagine what whoud happen if the camera was hand held
>and the mirror slapped!

The mirror in the square-format medium format camera is far larger
(and probably more massive relative to the overall camera/lens mass)
than the mirror in a 35mm SLR, so it could present more of a problem -
though I find the damping affect of hand-holding sometimes an advantage.
BTW, some particularly strong and sturdy-looking tripods succeed
in sustaining vibrations for remarkably long times - sometimes
floppy and unsteady-looking tripods actually have better damping.
Hope This Helps