Archived posting to the Leica Users Group, 1998/11/22

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Subject: Re: [Leica] test for film speed
From: Eric Welch <ewelch@ponyexpress.net>
Date: Sun, 22 Nov 1998 17:21:12 -0600

>OTOH, if you are culling evidence to support a pedantic dissertation
>admonishing the film's manufacturer to re-label their product's ISO
>rating, then Erwin's test would be the more effecacious.

Not that I'm picking on you Nigel, I really am not. But I see Erwin's
advice as a very simple, practical thing to do to really know how your
lenses, camera, film, developer and technique work -- compared to anyone
elses. 

Just because one might come up with an EI of 320 or 250 or even 200 for
Tri-X instead of 400 is more a function of that than it is a reason to
criticize Kodak. They develop their films according to a specific standard,
not in terms of the real world. It's for us to determine how our equipment
and technique responds in contrast (pun intended) to that standard.

Many people are happy not to calibrate their own system. They do things by
feel. But to get the utmost performance out of a film (as Ansel Adams says,
use the minimum exposure to get the right shadow detail and no more) one
has to calibrate. 

For a more precise system than Erwin proposes without getting too fussy
(like "Beyond the Zone System" gets) is to get Adams' books and read them
very carefully. Anyone can learn to do fine black and white work with just
those books, if they try.
- -- 

Eric Welch
St. Joseph, MO
http://www.ponyexpress.net/~ewelch


According to my calculations, the problem doesn't exist.