I recently bought a 4 x 5 Tachihara camera and fitted it with a zone plate.
I've been using zone plates on hand built cameras for several years. Large
format photography is new to me. So far I've been fiddling with the camera
and reading a considerable amount of literature on how to use it (for
example, Steve Simon's book). I have quickly encountered two troubling
aspects of the using the camera.
First, I can't see the image without a lupe. This makes composing on the
ground glass impossible. The ground glass is whatever ships as standard
equipment with the camera. Must I 1) upgrade the ground glass to a Fresnel
(will this solve the problem?), 2) buy and use a comparable real lens to
compose (a very expensive choice), 3) check my composition with Polaroids
(an expensive alternative)?
I should mention that I'm used to pinhole cameras without viewfinders, but I
thought I'd have the luxury of seeing an image on the 4 x 5 ground glass.
The second problem is that the camera seems to be in focus through a wide
range of focal lengths. I can't see any difference between the focus quality
at 150mm (which the zone plate is designed for) and, say, 170mm. The
magnification changes, but the focus stays the same. I can set the focus at
infinity by measuring the distance from the film plane to the zone plate.
However, the fine adjustments of focusing with tilts and swings seem at this
point impossible.
I'd appreciate your help.
Chris
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