Samsung GX-1L Using the Built-inFlash, Example), Sensitivity, Built-inflash guide number, Built-inflash guide number, L2 = 3.9 ÷ 5 = approx. 0.8 (m)

Using the Built-in Flash

Distance and Aperture when Using the Built-in Flash

A set criteria is necessary between the guide number, aperture and distance when shooting with the flash. Calculate and adjust the shooting conditions if flash is not sufficient.

Built-in flash guide number

Sensitivity	Built-in flash guide number
ISO 200	15.6
ISO 400	22
ISO 800	31
ISO 1600	44
ISO 3200	62

Calculating Shooting Distance from Aperture Value

The following equation calculates the distance of the flash for aperture values. Maximum flash distance L1 = Guide number ÷ Selected aperture Minimum flash distance L2 = Maximum flash distance L1 ÷ 5*

*The value 5 used in the formula above is a fixed value which applies only when using the built-in flash alone.

Example)

When sensitivity is [ISO 200] and aperture value is F4 L1 = 15.6 ÷ 4 = approx. 3.9 (m)

L2 = 3.9 ÷ 5 = approx. 0.8 (m)Therefore, the flash can be used in a range of about 0.8 m to 3.9 m.

The flash cannot be used when the distance is less than 0.7 m. When the flash is used at closer than

0.7m, it causes vignetting in the picture corners, light is distributed unevenly and the picture may be over-exposed.

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