1y mind with the y 
of me over the sn. 
, but that this ing, 
my most well-founie 
category and ty 
or photogrammep. 
fy 
confer important 
an 
raphic plotter of fiy 
h the servitudes du. | 
nown today have ber 
re always been Ty. 
nd optical devices lh 
the economy of fg 
> when plotting; iy; 
ith extreme ease anf 
8 the use of any fy 
ore than sufficient f; 
f the take camer 
vereoscopic observatin 
| and for the regi 
nages of the mark ay 
le image coming t 
hand any worry al; 
of the photograph ai 
le requisites fori 
‚in fact, the compl 
ative use and peni: 
pect to the observatin 
re it is equipped vil 
ain for the observatin 
ale which arise in fi 
g from the camers 
'w arrangement of i 
ight below, assures f 
yptical model. 
ly as it takes plut : 
endowed us; it shoul 
is an advantage of 
ding to the maxim 
lly at the plane of t 
‘hich some plotters 
servation in the mud 
types of plotters 1 
inciple. Thus falls s 
e even as ij De hi 
cal use, that the vari 
  
. of the enlargement of the images in the plotters based on the P 
mm the case of wide-angle cameras, is not of that importance with Which it is nor- 
even emt for the purposes of the stereoscopic viewing observation and the plotting 
mia fore that the introduction of the device designed to correct it is, for the plotters 
ae) a matter of technical preciousness but not a real requirement. All the same, 
s E S dne device, with which the Photostereograph Beta/2 is also equipped, 
functions with particular ease because, as already said, the images of the photograms in 
this plotter are already fused with the measuring mark while entering into the System 
that brings them to the observation eye-pieces. Le 
I have already noted that, with this plotter, it 1S easy to substitute th 
others of different geometric optical features, without disturbing it 
possible because the camera is an independent element which is mounted on the plotter, 
as one places a camera before a collimator to observe the latter's image through its lens. 
In the Photostereograph Beta/2, in fact the camera preserves its unchangeable elementary 
structure, lens focal plane, completely independent of the optical system carrying the 
images of the camera and the mark, which is part of the plotter. This device brings about 
the elimination of one of the principal difficulties presented by plotters based on the 
Porro-Koppe principle, in which the camera elements are part of the plotter itself, making 
the substitution of the camera with others of different characteristics very difficult and 
even impossible sometimes. 
This eharacteristic of the Photostereograph model 3eta/2 therefore removes the last 
and only objection raised by some against plotters based on the Porro-Koppe principle, 
but it must be pointed out that this is an objection which has a relative enough value in 
arrying out work on an industrial basis. In fact, if some one of the oldest organizations 
engaged in photogrammetric work still uses some old take camera, it is certain that it 
will be quickly forced to use modern take cameras, which have characteristics and achieve 
performances absolutely superior to the old ones: and, since the format of these cameras 
and their geometric features are being modified in agreement with the same elements of 
the plotters, it is obvious that this necessity is destined to disappear. On the other hand, 
if one were to wish to use photographs taken with old cameras with the Photostereograph 
Beta/2, it would be enough to have two cameras for them equipped with optics having 
those characteristics which the manufacturer, the O.M.L, has developed for every requi- 
tement, and the total cost of which is modest enough, since they consist of the metal 
housing that carries the focal plans and the lens itself. 
With the Porro-Koppe principle, there nee 
e cameras with 
S adjustment. This is 
d be no worry about correcting the distor- 
sion, since it is automatically corrected. There is thus no need for the correction plates 
and the other mechanical devices, whose cost is not much different from that of the two 
cameras needed for the Photostereograph Beta/2. 
l've referred to this problem in order to emphasize tl 
tion achieved with the new instrument, 
arent tendency, which wants to equip 
asimilar complex of requirements, mean 
than on the use of the instrument. 
It is my opinion that it is better to reserve one single geometric characteristic to the 
‘meras of the plotters or to the mechanical devices that replace them in other types of 
thiters, and that it is better to transform the original exposures so that they take on these 
tharacteristics, whatever the characteristics of the take camera may be. This can easily 
Ck with the orthoscopic Photoprinters, against whose use there has been no 
m CAR Since the onset of the film take cameras and following the consequent 
e bias against using printed photographs in plotting rather than the original 
ex i je : NS inni 
SINGEN, as was then held indispensable, in order to assure precision, at the beginning 
 photogrammetry. 
lt is, in fact, possibl 
1e practical and economic solu- 
but I have allowed myself to disagree with the 
plotters with every means possible so as to meet 
S which have their influence on the cost not less 
e, with the orthoscopic Photoprinter, to make new photographs 
5 
orro-Koppe principle, 
  
  
  
  
  
  
  
  
  
  
  
  
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