Olympus-OM
[Top] [All Lists]

Re: [OM] Body Cap with a hole, is pinhole "lens"?

Subject: Re: [OM] Body Cap with a hole, is pinhole "lens"?
From: Moose <olymoose@xxxxxxxxxxxxx>
Date: Sat, 31 May 2003 16:46:05 -0700
I suspect the fuzziness was a result of a poorly formed and likely too large hole. If you check the web resources on this subject, you will see how important a very smooth and thin edged hole of proper size is. And how relatively difficult such a hole may be to produce. The optics are based on diffraction at the edge of the hole (The very thing that causes loss of sharpness at very small apertures in lenses!). The bigger the hole, the less of the total light is properly diffracted and the fuzzier the picture. Since it is the interaction of the light waves with the edge of the hole that does the work, the accuracy and smoothness of the circle is a very important factor in performance. In theory, the edge of the hole should also be as thin as possible, hence the techniques that abrade a hole in thin material.

Moose

Lama-Jim L'Hommedieu wrote:

I made a pinhole camera with the "objective" about 1" from the film plane.

I poked a hole in aluminum foil and mounted it on a cardboard tube (okay, it 
was a toilet paper roll!)

I made 4 film guides with pushpins, and loaded it with a 90mm stip of Tri-X.  
It worked but I was only able to make a contact print
24mm x 90 mm.  It's probably just as well because even at that size it was 
blurry and of course, the cylindrical shape of flat film
plane gave me additional distortion.




< This message was delivered via the Olympus Mailing List >
< For questions, mailto:owner-olympus@xxxxxxxxxxxxxxx >
< Web Page: http://Zuiko.sls.bc.ca/swright/olympuslist.html >


<Prev in Thread] Current Thread [Next in Thread>
Sponsored by Tako
Impressum | Datenschutz