"Diaphragm vibrations"? Good lord. Is the mirror/shutter silent? That's another one making the rounds.
Where do these questions come from? Is there a room full of obsessive-compulsive worry warts somewhere?
I'm right. The world has gone mad. I use OM - 2,2n and 4Ti bodies with lenses from 28 - 300mm.+1.4 converter. The OM system was introduced to be largely handheld. The last thing I would consider is diaphragm vibration, but if in dought, use a GOOD tripod.
I'm into painting with light - NOT painting by numbers!