# Detailed oper ations – Sony HVL-MT24AM User Manual

## Page 37

HVL-MT24AM_GB 2-889-493-01 (1)

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Detailed oper

ations

When twin flash units are at different power level settings

The values given in the preceding tables for the twin flash units assume that both

twin flash units are set at the same flash level.

When they are set to different flash power levels, the aperture needed for correct

exposure can be calculated using the following equation:

Aperture*
= (A flash aperture)

2

+ (B flash aperture)

2

Example:

Using a 100mm F2.8 Macro lens with a pair of twin flash units with no
arm, “A” flash is set at a power level of 1/8, “B” flash unit is set at 1/16, and
the magnification ratio is 1:1
The A flash aperture set at a power level of 1/8 is f/19 and the B flash aperture set

at a power level of 1/16 is f/13 (refer to the table on 36 page).

Apply these results in the above equation.

19

2

+ 13

2

= 361 + 169 = 530

22

Therefore, in the above example, an aperture setting of f/22 will give proper

exposure.

* When both twin flash units are used.

Continued on the next page