1
THE (\JElil LüILD E4 AUTCFCCUSING ENLARGER-RECTIFIER
by Robert Scholl
UILD HEERBRUGG LTD
In the development of the new Uild E4 Enlarger-Rectifier, good use
has been made of the knowledge gained from practical experience
with the Wild UG1 Enlarger and the Uild E3 Enlarger-Rectifier. Since
the basic construction of the E3 has proved entirely sound, there
was no reason to change it. The elements for control of the auto
matic sharp focusing have, however, been simplified and in addition
several new features have been provided on the E4 so as to make
its operation easier.
Like its predecessor, the E4 belongs to that group of rectifiers
having a vertical optical axis and a projection table rotatable
about two axes with a horizontal zero position. The five degrees
of freedom of the instrument, namely the enlargement U, the two
table tilts/3 about
about the x axis and the
made on a horizontal plane or on one that is inclined in space.
Since all the above-mentioned movements are provided with scales,
the E4 can also be used for rectification using given values, e.g.
data obtained from measurements on horizon camera pictures or
from Autographs.
The ranges decided upon are as follows:
for the enlargement V, 0.8x to 7x
for the table tilts , +15^ each
' y 7 -
0 sin U), where f is the focal length
f that of the aerial camera, one can
c 7
From the equation sin/° =
of the rectifier lens and
compute the largest nadir distances V? with which rectification in
a single step is still possible. The maximum nadir distances for
the most customary camera focal lengths f are listed in Table I.
It is interesting to note that the values of the former in grades
correspond to those of the latter in centimeters: