Why would the edges of the frame suffer from vibration induced blur more than the center?
Was one side of the frame more blurry than the other?
The camera is a rigid body and all parts of the frame are exposed equally.
Q. Why would the edges of the frame suffer from vibration induced blur more than the centre?
A. In the case of the Pentax, and my work with it, the reason seems, to me at least, to be something to do with the manner in which the two curtains open up and close when making the slit that crosses the film plane. I guess that the initial jarr at the start of the opening of the two blinds is high enough to cause a slight movement in the body and that dies down to negligible levels and then hits again with a bang as the travel is completed.
Q. Was one side of the frame more blurry than the other?
A. Where I noticed the effect to be worse was in a series of landscape shots of a harbour where the masts at the extreme right of the transparency were really badly out of focus. I was shooting with slow speeds and small apertures. I am no longer sure which side of the camera the Pentax blinds started their travel, but if from left to right, and you consider the film to be upside down, it would perhaps indicate that the effect was worse at the start of the exposure than the end of it.
The camera is a rigid body and all parts of the frame are exposed equally.
I agree that it´s a rigid body, the reason I bought the damn thing because the alternative, a Mamiya RB or RZ would be like a sail down at a harbour. (It matters because I live on an island.) Having already lost my shirt on a Bronica 6x7 also bought because I thought it rigid, prevented me being bitten by that same dog twice.
As for the exposure being equal, that´s what they all strive for but do not always manage in real life. In fact, there´s a school of thought that says that it was only with the electronically controlled shutter in the F3 that even Nikon managed that fine trick of perfect exposure across the frame.
Difficult on 36x24mm, probably impossible over 6x7!
Cheers
Rob C