It could be due to camera shake. To eliminate this as a possibility
then I would advice you to shoot a roll with the camera tripod mounted
and inspect the results closely using an 8x lupe or higher. If you
still have soft images then post back here as there are other factors
that could be involved such as the focussing screen spacing needing to
be adjusted.

The 330 is much lighter than the 33's I used to use that helped cradle the
camera as you do with the rack focusing. So it could be shake but then it
would show over all the image.

I'd check the lens fitting as it may not be fitting correctly and may just
show signs of image softening due to poor registration. I found the lenses
to be crisp and sharp albeit contrasty. But then I like that.

Duncan

exceptionally sharp print. <<<

Peter:

Do you wear glasses, especially bifocals?

Perhaps you're old enough to have prespyopia... the inability of the eye
to focus sharply on nearby objects, resulting from loss of elasticity of
the crystalline lens with advancing age.

If one of the twelve frames was sharp then prespyopia may be the cause,
and I think that if that's the case then all you need is a minus lens in
your waist level finder.

I get around the problem by using a prism on my 220F.

Jim Hemenway

I doubt if your sharpness problem is equipment related, since it doesn't
occur on every image.  My guess would be it's something you are or are not
doing.  I'll pose some questions to further your investigation.

Do you need glasses?  Bifocals?

Do you use the pop-up magnifier when focusing?  You should.  All the time,
every time.

Is your focusing screen, mirror and focusing lens clean or loose, etc?
Do you use filters?  If you do, the filter needs to be on the focusing
lens when you focus.  A filter with 2 air/glass surfaces changes the
optical path which can affect the focus point.

Are any of the "unsharp" pictures shot with the lens wide open or fully
stopped down?  This can affect apparent image sharpness due to lens
aberrations, which mostly disappear after stopping down 2 stops, or image
diffusion, which begin to occur as you approach the higher f-stop numbers.
Try to use a moderate f-stop range from at least 2 stops down to 2 stop up
from minimum aperture.

Lastly, here's a quick test you can do to check if focus is out due to
problems in the camera.  Mount the camera on a tripod facing a blank wall,
level the camera so it is parallel to the wall, place a focusing target of
sufficient size that it fills the viewfinder entirely.  I use a page of a
newspaper, which is mostly fine print.  Make sure it's absolutely flat to
the wall.  No sags or bulges.  Evenly illuminate the target either with
natural or artificial light. A large north facing window opposite the
wall, behind the camera will work.  You just want the light even and
diffuse.  With no film in the camera, open the back and tape a piece of
fine ground glass over the film gate. Make sure the textured side is at
the film plane and pointed toward the lens. If you don't have any ground
glass, substitute any smooth media that will hold the image. Rear screen
projection material is good. In a pinch, I've used a smooth piece of
heavy waxed paper.

Now, with the taking lens wide open, focus on the center of the
focusing target as you normally do.  And use the focusing magnifier.
Remove the focusing hood and place it over the film gate to make it easier
to view the projected image. Is it sharp or out? Now, refocus on the film
gate image making it as sharp as you can.  Examine the image focused on
the normal viewing screen. Is it in focus?  In both cases, if everything
is working properly, the images should have been in focus for both
procedures.

Repeat the test with the taking lens stopped down to a mid-f-stop, f8 is
good.  Compare the results.

Now, without changing the set up, make a test carefully focusing in
the normal manner using medium speed b&w film shooting wide open, stopped
down mid-way, and stopped down all the way.  That chromogenic b&w film
that can be processed in color chemistry is fine. You just want to check
if things are in focus on film when they are in the viewfinder. Don't make
prints. Examine the film directly with at least an 8X loupe.  If images
are out, take your camera and lens to a tech and have it checked it out.

I know that the Mamiya TLR lenses give excellent results having owned a
C-220 and a couple of lenses years ago, that I shot with professionally --
glamour, advertising, editorial, PR, etc.  Never received any complaints
from any ADs or editors about "soft" or out of focus images, unless, of
course, they were suppose to be.  ;-)  The lens(es) you're using are the
black barrel type? Right? Not the chrome ones?

Stef