Digital BW, The Print

Mark writes:

> ... if you look into the viewfinder of a
> Hasselblad (or any camera), you are not
> "focusing" on the ground glass, right? You
> must be focusing on the distance of the
> subject.

Not so.  You are focusing on the ground glass.  And since it is only a few
inches away, if you are farsighted, you won't be able to focus on it without
glasses.  Using the little magnifying lens can help here.

> If I look through the viewfinder of my hassie,
> and I'm focusing on a subject that's 25 feet
> away, are my eyes "focused" at 25 feet, or
> are they focused on the distance to the viewfinder
> ground glass?

They are focused on the distance to the viewfinder ground glass.

If you are using a prism viewfinder, the same is true, except the focus
distance of the ground glass is slightly different.

All SLR viewfinders work in this way.  Usually the viewfinder system is set
up so that the ground glass has a "virtual" distance of about 1-2 metres,
which is a distance at which most people can see pretty clearly.  However,
when you are looking at the ground glass directly without any intervening
glass, as in the waist-level finder, you must focus on the ground glass
screen directly, at its actual distance from your eyes.  If you cannot focus
at distances of less than a foot or two, it can be hard to see the ground
glass clearly without holding it so far away that fine detail is not clearly
visible.  The solution is to flip up the little magnifier, and, if necessary
to replace the standard magnifier with one that matches any correction you
need in your vision.

> I guess I know the answer,because I see fine
> through the camera, even without any diopters ...

Are you using the standard WLF or a prism finder?  Prism finders are
preferable if you are farsighted, for reasons stated above.