Most people shoot the 67 with the mirror lock-up whenever possible. Even so, shutter bounce is a real problem. See http://luminous-landscape.com/reviews/cameras/pentax67ii.shtml (which is, on the whole, a *very* favorable review of the 67) for discussion and examples of the effect. All but the earliest ones have the mirror lock-up capability.
-- Mark Roberts Photography and writing www.robertstech.com
