Archived posting to the Leica Users Group, 2001/04/07

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Subject: [Leica] Re: Re: what's the point of a leica pinhole???
From: Jim Brick <jim@brick.org>
Date: Sat, 07 Apr 2001 15:44:50 -0700
References: <200104062027.QAA10681@unix3.netaxs.com> <20010406171539.F20312@oven.com>

Oh my gawd... all of this and you still have a pinhole photograph! That
looks like a pinhole photograph.

Jim


At 01:37 PM 4/7/01 -0400, Dan Post wrote:
>Actually, the focal length would be from the  plane of the pin-hole to the
>film plane- I made a pinhole in a piece of shim brass, and then trimed it to
>fit and old 39mm filter ring. The thread is not the same as the camera, but
>it holds on enough for the use of the pin hole. The distance in this case is
>about 42mm, so it is pretty much like a normal lens as far as perspective is
>concerned.
>Incidentally, the best pin holes I have made were by taking a piece of .030"
>shim brass- I got it at the local Ace Hardare!, and taking a sewing  machine
>needle- the 'ball point' kind that is used for sewing polyester. The point
>is not so much 'sharp' as rounded as these needles were designed to open up
>the fabric and go between the fibres instead of going through them-
>something about maitaining the elasticity of the fabric's seams. The needles
>of this type are superb for making pin holes
>You take a piece of the shim brass, and lay it on a scrap of hard wood- I
>have a little piece of oak that I use for various things around the house,
>and it works fine.
>Lay the brass on the wood, and make a 'dimple' in the metal- like a tiny
>repoussee dot, and don't go all the way through!
>Now take the piece of brass, turn it over so the dimple is now a small bump,
>point ing up. You can then take a piece of 1500 grit wet/dry sandpaper, and
>with a light circular motion, start sanding the bump off the metal surface.
>You will get a pinhole and it will have a knife edge, very thin and the
>refraction will be a lot better than just poking a hole in it, or drilling
>which makes the hole like a 'tube' through the metal, and the image is not
>very well defined as a result. When you finish, examine the hole- it should
>be as round as possible, and you may have to take three or four stabs at it
>before you get one with smooth round edges without burrs!
>
>It is pretty much an experiment in refraction, and the images are really
>soft with a 35mm camera, but it is a fun way to fritter away an afternoon!
>
>Happy long exposure snaps!!
>
>Dan

In reply to: Message from Kyle Cassidy <cassidy@netaxs.com> ([Leica] what's the point of a leica pinhole???)
Message from Jeff Moore <jbm@oven.com> ([Leica] Re: what's the point of a leica pinhole???)