Konica Minolta T-10A, Инструкция по эксплуатации

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54
[Conforms to JIS]
Since the brightness at the measurement plane is proportional to the cosine of the angle at which the light
is incident, the response of the receptor must also be proportional to the cosine of the incidence angle.
The graph above shows the cosine correction characteristics of Konica Minolta Illuminance Meters T-10.
The cosine error of T-10 are shown in the table right.
Class General class Precise General class AA General class A
f
2
(%) 1.5 3 6
f
2
can be calculated as follows.
In addition, f
2
* (
θ
) is represented by the following equation.
The following shows the angle deviation from cosine characteristics in terms of the incident angle of
the light for reference.
Oblique incident angle General class Precise General class AA General class A
10° ± 1% ± 1% ± 1.5%
20° ± 1.5% – –
30° ± 2% ± 2% ± 3%
40° ± 3% – –
50° ± 4% ± 6% –
60° ± 5% ± 7% ± 10%
70° ± 8% – –
80° ± 20% ± 25% ± 30%
The instrument has the following optical characteristics of the oblique incident lights denoting that this
is an illuminance meter conforming to JIS general class AA (f
2
=3% max.).
60 60
40 40
20 20
0
100 %
80
%
60
%
40
%
20
%
80 80
Konica Minolta Illuminance Meters
T-10A/T-10MA
Ideal curve
Cosine Correction Characteristics
f
2
=
0
180
f
2
* ( θ ) sin2 θ θ
d
ʃ
80 π
f
2
* （ θ ）=
Y
0
cos θ
Y（ θ ）
­1 100 （ ％ ）
Y
0
: Vertical illuminance values
Y (
θ
) : Illuminance values in the incident angle (
θ
)