Re: Fun!!! Large Format Lens Question. Low tech answer

----- Original Message -----
From: "Janet Neuhauser" <jneuhauser@wavecable.com>
To: <alt-photo-process-l@sask.usask.ca>
Sent: Friday, February 25, 2005 8:31 PM
Subject: Re: Fun!!! Large Format Lens Question. Low tech
answer

>
>
>> What would be real fun is to have a on line
>> competition or on
>> line exhibit of images using home made simple lenses or
>> low tech lenses..
>> These lenses take images that really lends themselves to
>> alternative
>> processes..... The competition could be the process of
>> your choice
>> submitting a good clear digital image of your hand
>> crafted lens along
>> with a taken with it using alt processes.............
>> The competition
>> should probably exclude pinhole
>
> What would happen if you put the lenses over a pinhole?
>
  There is a relationship between the position of a stop and
the performance of a lens. In a very simple lens the
introduction of a stop will reduce the spherical aberration
and coma and reduce the effects of some other aberrations.
Box cameras used simple meniscus lenses. A meniscus lens is
one where both surfaces are curved the same way. There is an
optimum shape for this kind of lens for best correction.
When its combined with a stop at the right distance the
correction is even better. Such simple lenses are capable of
surprizingly good images.

---
Richard Knoppow
Los Angeles, CA, USA
dickburk@ix.netcom.com