The GranView 4x5 had the option of a magnifying lens in the centre of what
amounted to its ground-glass cover. It was/is extremely useful if you want
something better than scale focussing while handholding the camera. It was
nothing more than a simple lens mounted flat in a hole drilled in the plastic
cover, but worked well enough for the purpose. (Because of the unusual design
of the spring back, it was not flush against the GG, and so didn’t anything
else to keep in far enough away to focus.)
I made a similar modification to a 4x5 folding hood. I used a 7x B&L
Hastings magnifier and painted the transparent magnifier housing black.
It was mounted on axis. The result was a highly magnified and very bright
image of a small portion of the scene. This allowed hand-held accurate
focusing under a wide range of conditions. It worked very well.
I don't quite understand the reason for the magnifier since I
prefer to be able to move a magnifier around.
