[AZ-Observing] Re: Eyepiece religions
- From: Rick SCOTT <rmscott@xxxxxxx>
- To: az-observing@xxxxxxxxxxxxx
- Date: Wed, 16 Apr 2008 21:26:56 -0700
Steve,
You may learn some from plain old graph paper like distortion, chromatic
aberration and softening in the corners, but there is much more that can
be measured using the appropriate test targets. Below is a link to a web
site put together by Norman Koren, an ex Hewlett-Packard engineer and
fine photographer, with tons of great information on everything
technical you may want to learn about film and digital photography. You
may even learn some things that will cause you to spend more money on
better equipment, but as you well know, good equipment is worth it.
http://www.normankoren.com/Tutorials/MTF5.html
This link will take you to his lens testing page, but I'm sure you can
figure out how to find the rest of his wonderful site. I've spent many
very worthwhile hours absorbing what he presents.
Enjoy Learning,
Rick
-------- Original Message --------
Subject: [AZ-Observing] Re: Eyepiece religions
Date: Wed, 16 Apr 2008 20:19:30 -0700
From: Steve Coe <stevecoe@xxxxxxxxx>
Reply-To: az-observing@xxxxxxxxxxxxx
To: <az-observing@xxxxxxxxxxxxx>
Brian, et al;
I would seem that the makers of eyepieces want it that way. I don't know
enough of the science of optics to speak too much about using an optical
bench. But, in the era of the digital SLR camera could not a
knowledgeable person aim the eyepieces at a flat sheet of graph paper,
take an image and learn quite a bit from that image?
Just thinking out loud;
Steve Coe
-----Original Message-----
From: az-observing-bounce@xxxxxxxxxxxxx
[mailto:az-observing-bounce@xxxxxxxxxxxxx] On Behalf Of Brian Skiff
Sent: Wednesday, April 16, 2008 4:06 PM
To: az-observing@xxxxxxxxxxxxx
Subject: [AZ-Observing] Re: Eyepiece religions
It's too bad the marketplace has made it difficult to determine actual
facts about the eyepiece designs as actually sold, so as to allow the
discussion to be brought into the realm of quantitative comparison
rather than "religion". The US magazines (at least) provide no such
information, and without a pretty good optical-bench set-up, it would be
a lot of work (and expense) to reverse-engineer the commerical products.
Maybe some patent searches would turn up actual specs you could run into
an optical-design program to yield details about image quality, color
aberrations, field curvature, distortion, etc. I know this was done for
the original Nagler design (it was in an issue of 'Telescope Making'
back in the 80s), but what about the many newer styles that have come
out since then?
\Brian
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