Field Of View - Extech Instruments 42545 User Manual

Field of View

The meter's field of view is 50:1. For example, if the meter is 12 inches from the target
(spot), the diameter of the target must be at least .24 inches. Other distance ratios are
shown in the field of view diagram.
The target should always be larger than the spot size. The smaller the target the closer you
should be to take measurements. In instances were accuracy is critical make sure your
target is at least twice the spot size.
Note that measurements should normally be made less than 3 feet from the target. The
meter can measure from further distances but the measurement may be affected by
external sources of light. In addition, the spot size may be so large that it encompasses
surface areas not intended to be measured.
Diameter of Spot
0.5"
25"
36"
Distance to Object
0.72"
50"
5
2"
1"
100"
Model 42545 Version 1.1 12/ 04