Hi Matt
The Lens format has changed in the new lens.
It depends on why the lens is faulty as to how easy it will be repair.
You would need to send the camera in to Peter Wood with some example shots and he will put it on our test rig for examination....... it may be best to ask for an estimate

Mamiya Service
JP Service Solutions
Hempstalls Lane
Newcastle
Staffs
ST5 0SW

By Matt Fraser on Friday, October 31, 2003 - 02:23 am:

I recntly purchased a used 645 Mamiya Sekor C f1:3.5 35mm lens serial no.32657. The lens is in immaculate condition, no marks,scrathes,rattles or damage of any kind.

Other than style of markings it looks identical to the current model C f1:3.5N 35mm lens, external specs.& weight are the same.

However on testing the lens I found it to give poor performance, very soft edges & corners. It is easily visible on a polaroid! well below pro standard.
performance improves as the lens is stopped down.
I have used the current model N lens and found it to to have excellent sharpness across all apetures
My question are,

How old would this lens be?

Has the internal element/grouping design changed?(it would be unlikely that it would have, given that the lenses are physically identical)

If the lens design has not changed can the lens elements be recalibrated to fix this problem?