
Stereoscopic restitution of vision 303
3.5
z
max
Prohibited area
Z
p
o
Zone of observation
3
2.5
0.5
0
0.5
0.75
1
1.25
1.5
1.75
2
2.25
2.5
1.5
2
Prohibited
area
1
f
f
f
f
S
Figure 13.11 Zone of observation possible without ocular strain as per the focal lengths
between 16 and 32 mm and also for a zone of observation more than 1.5 m (all values
can be >1.5 m for z
p
0
in this case). On the other hand, if the zone of observation
is between 1 and 1.5 m, it is limited (depending on f ) around the distance z
p
0
that
must be the distance from the main object observed. Viewing with wide focal length
f > 48 mm is done with depth flattening. Near vision (less than 1 m) is very difficult.
It