Armasight DAB10X42RF0ARM1 10x42 Binoculars - Manual (Page 14)

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L = H/ω = 25/60 = 0.4166km = 416.6m
Therefore: the distance between the observer and the adult is 416.6m.
For example 2:
There is an adult whose height is 1.70m (H = 1.70m).
The Vertical View Angle of the adult is 4 decade mils (40mils).
L = H/ω = 1.7/40 = 0.0425km = 42.5m
Therefore: the distance between the observer and the adult is 42.5m.
Figure 13. Ditance Measuring
4) How to Measure a Object’s Size (Height and Width) Using
According to the formula for distance measurement, you can calculate the height using:
H = L × ω.
When measuring the size, you first estimate the distance to the object, then measure the View Angle.
With these measurements, you can calculate the height of the target using the formula.
For example:
the distance is 0.6km between the observer and the object. You can measure that the Horizontal View
Angle is 6 decade mils (60mils) and the Vertical View Angle is 3 decade (30mils). So, using the formula
you can get:
The height: H = 0.6 × 30 = 18m
The width: h=0.6 × 60=36m
5) quick Distance Measurement
The reticle is consisted of one horizontal line and a diagonal line. And regards the H=2m as known
height to quickly measure the common target such as vehicle or adult. Placing the target projection
between the 2 lines, The reading on the tangency of the projection and diagonal line is the target
distance (line value:100m). as shown in Figure 14, the distance between the target in 2m high and the
observer is 550m.
Figure 14. quick Distance Measurement