----- Original Message -----
From: "Andrew Fildes" <afildes@xxxxxxxxxxxxxx>
To: <olympus@xxxxxxxxxxxxxxx>
Sent: Monday, February 12, 2001 5:42 AM
Subject: Re: [OM] pinhole body cap
Andrew,
I think the ground down hole works best
because-withcare- there is less material thickness to distort light rays
which are coming at an angle to the axis of the hole. I find it best to
punch dimple, stone down, then as hole appears carefully shape with point of
needle from inside of can and then stone down again. Done carefully it is
possible to obtain a very good result.Check with a magnifier. I find hole
sizes of about 0.030" or 0.75mm give exposure times on paper of about 3 mins
in good light. One day when I get time I will use the same method with a
smaller can and cut film. Or I will try my present setup with film if I can
obtain some cheap sheet in sizes about 6x8" or above! Life is never dull!
Regards,
John Duggan,
Wales U.K.
> One of the reasons that 'ground down dimple' holes seem to work best, I
> believe, is because a sharp edge to the hole improves the image (reduces
> diffusion or diffraction - I can never remember). > Andrew
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