Re: Pinhole Question?

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From: Dave Rose (photo@wir.net)
Date: 01/06/01-08:25:49 PM Z


Hello Sam,

I'm putting the finishing touches on a 12x20" 'superwide' pinhole camera
tonight. It's fabricated from sheet metal (galvanized stove pipe) with a
minimal wooden framework inside for added rigidity, and a brass swing-type
shutter. It has a 9" 'focal-length', a .0235" pinhole, and the film is on a
curved plane, yielding a 130 degree angle of view. I'm planning to shoot
lith film in it tomorrow. WHOO HOO!!! I'll print gum or cyanotype/gum
prints from the negs.

I'm no expert on pinhole cameras, but I'll try to answer your question. The
statement: "size of the pin hole is directly related to angle of view" begs
the question: what exactly is "directly related"? Given the many factors
involved, I don't think it's quite that simple, but in general, yes, a
larger pinhole will yield a wider angle of view. The down-side is the
decreasing resolution as the pinhole diameter increases (from the 'optimum'
diameter). The best advice for your friend is to make the pinhole with
great care in very thin material, e.g. .001 or .002" brass shim stock,
thereby maximizing the angle of coverage, and quality of image.

With a wide angle pinhole and a flat film plane, your friend will experience
underexposure at the corners of the film - regardless of pinhole diameter.
Not necessarily a "bad effect". His camera will also produce true
rectilinear perspective versus the barrrel distortion that our pinhole
cameras with their curved film planes exhibit.

Hope to hear from you again.

Best regards,
Cactus Cowboy
Big Wonderful Wyoming

> Hello Everyone
> This is my first post to the list so please forgive any lack of etiquette
on
> my part.
> I have been making pinhole cameras out of cardboard tubing (basically a
> version of the oatmealbox version) and having a great time with them. All
of
> the sudden everyone
> I know wants to make pinhole cameras, a friend of mine was telling me he
> wanted to make one but wanted to make it square and still get a "wide
angle "
> look to it. He is somewhat knowledgeable about these things and suggested
> that the size of the pin hole is directly related to angle of view. Is
that
> true and if so how does that work?(is larger more wide ect.)
> Thanks
> Sam
>


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