Re: slide vs neg

[P3D Paul Talbot <ptww@xxxxxxxxx>]

The book I mentioned in the previous post is called "The 35mm Film
Source
Book."  It was written by Marc Levey, (c) 1992 Focal Press.  The ISBN is
0-240-80125-3.

Note the copyright date; some of the information is already out of date,
of course.  Early in the book he makes a comparison of "today's films"
to 1985 films.  Keep in mind this would be '91 or '92 vs. '85. A table
is presented on the topic of film speed vs film grain:

                       approximate
                       comparable
                       quality in
     Today's film      1985 film
     ------------      ---------
      ISO  100       ISO 32 or less
      ISO  400       ISO 100
      ISO 1000       ISO 400

* * * * * * * * * * * * * * * 

On the subject of personal EIs for exposing various films, the panel of
expert photographers assembled by the author for the research that went
in to the book, the following averages were computed:

Film                    Low-contrast EI          High Contrast EI
----                    ---------------          ----------------
K25                           32                        25
K64                           80                        80
K200                         250                       250
Ek50 HC                       50                        64
Ek64x                         80                        64
Ek100 Plus                   100                       125
Velvia                        50                        50
Fujichrome 100 RDP           125                       125

* * * * * * * * * * * * * * * 

Resolving power in lp/mm (I do wonder if there is a typo in this chart;
the accompanying text discussion did seem 100% consistent with the
numeric data.)

Film             lp/mm
----             -----
K25               100
Ek100HC           100
Velvia            160
Fuji 100 RDP      125


(continued next post)

Paul Talbot


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