Re: "rings" on photos. What could be the cause?

I see these sometimes, but not always. They usually seem to be related to a
light source, so i'd guess it's diffraction. try a shot away from any light
source and see if they're still there.
----- Original Message -----
From: "Justin Bell" <j.bell@paradise.net.nz>
To: <Pinhole-Discussion@pinhole.com>
Sent: Thursday, July 04, 2002 12:36 AM
Subject: [pinhole-discussion] "rings" on photos. What could be the cause?

> Hi. I've been playing around with pinhole photography, and I'm still in
the
> mode of figuring it all out.
>
> Recently, I decided to change the focal length from 110mm to about 35mm. I
> have an old Agfa Bily, and just removed the entire front end except for
the
> 'accordian' part, the pinhole lines up with the front of the camera.
>
> In doing so, I made another pinhole. But now I have tried 2 pinholes with
> the new modified focal length, and I'm getting 'rings' on the photo
> (http://soupisgoodfood.net/temp/pinhole.jpg, sorry for the poor photo, I
had
> to take a digi of it using my monitor as a lightbox :).
>
> I'm guessing I didn't see the rings before I changed the focal length
> because it fell outside the frame.
>
> What do you think is causing it? Pinhole too small/refaction of light? The
> fact that I made it from heavy aluminium foil (one of those pie trays that
> comes with frozen pies to be exact). The "drill" method?
>
>
> Thanks for any input.
> Justin.
>
>
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Received on Fri Jul 5 21:29:00 2002