Peter Alling posted:
> Subject: Here it is the perfect lens for the pentaxian with everything.
>
> http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=2912698133&category=30077
I've wanted one of those for a while. Haven't been able to
afford the ones I've seen advertised yet. (Not that they're
all that expensive, just that I'm that broke. Paying my HMO
premium and utility bills come first, if I actually manage to
do that this month.) $1.00 plus shipping ... Hmm ... wonder
how much the reserve will turn out to be.
Peter Smekal asked:
> Couldn't such a pinhole be
> easily be made out of a black body-cap, or would this give too much leakage
> of light?
I don't think leakage is the issue -- you need a really _neat_
hole, and I *think* the thickness of the material matters as
well (though I suppose one could scoop out plastic to make a
thin area in the center of a body cap, then drill the whole
through that).
This appears to have been made the same way as my own attempts:
cut a larger hole in a plastic body cap, then mount a piece of
metal with the pinhole in it covering the larger hole.
Peter ([EMAIL PROTECTED]) observed:
> I believe that it is possible to acheive such a tiny aperture with a drilled
> hole and superimposed aluminum foil with pinprick hole.
I've tried that. You'd be surprised at how hard it is to get
a *clean* *round* hole that way! After several attempts, in
which I did manage to get a "proof of concept" piece and some
sample images, I gave up on aluminum foil -- every image I got
was _fuzzy_, presumably due to irregularities of the holes.
(But I had infinite DOF so everything was _equally_ fuzzy.)
OTOH, it was a cheap way to explore things like multiple
copies of the image in one frame from multiple pinholes.
And enough to show me that the right camera for this sort
of thing would be an LX, because metering through a pinhole
is a pain. (Once I have a working pinhole and figure out
the effective f-stop of it, I'll be able to meter with a
normal lens and calculate from there, of course, so an LX
isn't _required_, thank goodness.)
(My experiments so far have been mounted in a screwmount
body cap, 'cause that's what I had spares of, but I did try
sticking that onto the Super Program with rubber bands.
At some point I'll modify a K-mount body cap too.)
I've also tried making holes in brass via different methods,
and have again had trouble getting a perfectly round hole
the size I want. It's probably trivial with the right tools,
but the most advanced thing I've got is a Dremmel, hand-held.
Eventually I'll luck into an unusually cheap pinhole,
AFAIK, most of these pinhole 'lenses' are made of brass.
(That is, the hole is in a small piece of brass mounted
in a plastic body cap.) I notice that this one is made
in steel.
Eventually, I'll stumble across an unusually cheap pinhole,
or I'll finally save up the money to buy one of the commerical
ones, or I'll finally manage to make a good one. I've already
got a small list of projects I want to shoot that require a
pinhole.
-- Glenn
