In article <32B54310.7292@psy.ulaval.ca>, everett@psy.ulaval.ca says...

>For a while, I have been thinking of getting into medium
>format, and last week I actually started handling some of
>these cameras to see how tempted I would be. I was
>surprised to find that the image obtained in the prism
>viewfinder was not as sharp as I had expected. In fact, a
>side-by-side comparison with a Nikon body and 50mm
>nikkor lens gave me a sharper image than I could get with
>an equivalent focal length in medium format (Mamiya 645,
>Bronica and Pentax were the models I tried). I understand
>that medium format negatives are larger than 24x36 and
>so a sharper final image will be obtained in theory, but is
>it normal for the viewfinder image to be less sharp, or
>should I keep looking for a medium format camera that
>gives sharp viewfinder images?

I am not familiar with newer Mamiya VF image quality,
but the old M645/645J/1000S series VF with standard prism
is quite sharp. A Bronica ETRS VF I looked into wasn't
particularly sharp. It appears that in MF cameras, as
in 35mm cameras, there is variation in VF image quality,
and the latest may not be the best...
BTW, having just reentered the MF arena, I am once again
struck by the fact that (everything being equal), the unit
film area quality of the MF (and more so in LF) is not up
to good 35mm unit film area quality, but the larger film
area does produce higher quality prints in a given print
size. Still, it is surprising to see graininess in 8x10
MF Tri-X prints when prints from 35mm Tri-X can look so
good...(and even more surprising to see grain in 8x10's
from 4x5 Tri-X...!). Larger film area does not cure all
ills, just reduces them... ;-)
Hope This Helps