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For example, if you are using two filters, one with а filter factor
of 2/3 and the other with а factor of 1 2/3, the filter factor of
the two together is 2 1/3 (2/3 + 1 2/3 = 1 4/3 or 2 1/3). То add
this compensation value to the meter's operation, press and
hold the ISO button an.d press the down control 7 times (6
times for the 2 whole-stops plus once more for the additional
1/3-stop). lf you are using ISO 100 film, the meter should now
read ISO 20. Now, each time you take а meter reading, the
Auto Meter IV F will automatically compensate for the light
absorbed Ьу the two filters.
ILLUMINANCE MEASUREMENTS
The Auto Meter IV F provides you with the means to
determine the illuminance, in lux (lx), of an amЬient light
source.
1. Attach the flat diffuser to the Auto Meter IV F.
2. Turn the meter оп, select amЬient mode, set the film speed to
ISO 100, and set the digital display to EV.
3. Position the meter so that it is near your subject, point the
receptor head directly at the light source you are measuring,
and press the measuring button to take а reading.
4. Use the EV indicated Ьу the meter and refer to the tаЫе 4 to
determine the illuminance. Find the integer value of the
meter reading in the left-hand column and the decimal value
in the top row. Where the row and column intersect is the
approximate illuminance measurement in lux.
For example, if the meter displays а reading of EV 10.7, the
row for the integer 1 О and the column for the decimal 0.7
intersect at 4200 lx.
• llluminance сап also Ье calculated using the following
formula:
IX= 2.5 х 2
EV
• For precise measurements of illuminance, use the Minolta
llluminance Meter.
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