When dealing with #3 shutters is there any difference in the smoothness and quie tness of the release between Compur, Copal and Proctor shutters? Is the compur less likely to shake as it releases? I understand from people that have used #3 shutters on long lenses that the Copal 3 releases with quite a klunck causing vi bration. The weight of some lenses mounted on #3 shutters, as for example 300 a nd beyond Symmars or Sironars should help dampen shutter-caused vibration, howev er my concern is with lighter lenses such as Apo Ronar 360, which relative to th e shutter are lighter than their sironars or Symmar counterparts. Compurs are m uch more expensive. Aside from their other advantages such as 1/3 stops and dura bility, are they worth the money as relates to vibration? One informat says Comp urs are quieter and soother.