RE: Pinhole Focus

>"Ian McKee" <photoian@earthlink.net> wrote:
>
>>Calumet sells a set of twelve pinholes ranging from .0059" to .032". I have
>>mounted these on a 4" x 5" camera and shot the whole series at an
>>arbitrarily selected bellows extension=focal length of 210 mm. With each
>>pinhole I get the same image and the same degree of sharpness. The only
>>variable is exposure time.As you might expect, the smaller the pinhole the
>>longer the exposure to achieve equal density.
>

>"Dieter Bublitz" <dieter@die-lochkamera.de> wrote:
>This has been done before - with opposite results. You can find an
>example of this in Eric Renner's book "Pinhole Photography -
>Rediscovering a historic technique" (Second edition) on page 129.
>There are 8 images of the same object taken with a Super Speed Graphic
>with a focal length of 2 1/4 inches and 8 different pinholes (f/22,
>f/32, f/45, f/64, f/90, f/128, f/190 and f/288). There are noticeable
>differences in sharpness from one image to the next.
>This is what physics is telling us and what innumerable pinhole
>photographers have experienced taking their images.

The pinhole range that Calumet sells would make lenses with f stops from 300
to 2100
when used on a camera with a 210mm extension. Eric's example is to show other
possibilities other then tack sharp. Ian's question has to do with optimum
size and
smaller apertures while Eric is describing the wonderful possibilities of
different focus
qualities using larger then optimum holes. I have never tested the
effectiveness of hole
size to sharpness or smaller then optimum holes, but I have enjoyed working
with big
apertures for the quality they give.

Chris Peregoy
peregoy@umbc.edu
http://userpages.umbc.edu/~peregoy
Received on Wed Dec 18 11:14:54 2002