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(669)
LONG DISTANCE PHOTOGRAPHY IN GROUND RECONNAISSANCE
AND THE POSSIBILITIES IT GIVES FOR PHOTO INTERPRETATION!)
an abstract of a lecture given at the World Congress by the Chairman
of the Military Section of Commission VII, Captain Ragnar Thorén,
Royal Swedish Navy.
In my report to the Congress, entitled *Photo-Interpretation in Military
Intelligence", the subject dealt with is based on Photo Reconnaissance from the
air and ground — terrain and sea — as well. In my daily work as a lecturer in
photo interpretation for Staff Officers and also as an ex-combatant officer in
the Finnish-Russian war, I have always found that top results are achieved by
the interpreter only when he has the opportunity of combining information
from both air and ground photographs. According to this and a desire expressed
by the President of Commission VII, Professor Robert N. Colwell, the above
subject concerning long distance photography had been chosen.
In order to illustrate the advantages of comparative analysis of aerial and
ground photos, I showed a series of slides of naval long distance photographs
in ground reconnaissance, taken by me in World War II, in comparison wit
some aerial pictures of the same objects, photographed simultaneously or on the
same occasion.
As an example of long distance cameras with Smith's mirror optics I show-
ed a picture of a Swedish-built reconnaissance camera, constructed by Mr. E.
Aulin, AGA, Stockholm-Lidingó. This extremely good instrument with a focal
length of about 59”
(150 cm) and as great
an aperture as 11,8”
(30 cm) is suitable for
photographing at
dusk. In the following
picture a fine Ame-
rican ship of the
Moore-McCormack
Lines was shown re-
corded with that ca-
mera from a relative-
ly short distance, 5
miles away: Rather Fig. 1. An American ship of the Moore-McCormack Lines pho-
small details of the tographed with a Swedish-built reconnaissance camera with
ship show up very Smith's mirror optics and a focal length of abt. 59" (150 cm)
well (see Fig. 1), and from a relatively short distance of 5 miles (enlarged photo detail).
the high quality of
the picture presents extensive possibilities of detail analysis.
1) NOTE: In connection with this article the reader is encouraged to refer to Figures 1 through
7 of another article by Captain Thorèn which appears elsewhere in these Archives. The article
is entitled “Photo Interpretation in Military Intelligence” and appears as Part IV of the Report
of Commission VII. Ed.
52
