Electronic Flash in Digital and Film Photography 339
are much darker or much brighter. This does not happen too often and does not need to be
considered too seriously when the fl ash is used as a fi ll-in light. Usually the measuring area
includes an arrangement of many brighter and darker shades, even in wedding photographs,
but you should be aware of this fact as it may come up, for example, in copying. You can
adjust for differences in the refl ectance values by setting the ISO to a lower value for brighter
subjects and to a higher value for darker ones. You can also use the fl ash compensation con-
trol. A 1 setting turns the fl ash off earlier than 0 to compensate for the lower refl ectance of
darker subjects.
Dedicated Flash in Digital Imaging
Most dedicated units are still based on the fi lm refl ectance and need a correction for the dif-
ferent refl ection values of the sensors. On the 503CW and 503CWD camera models dedicated
fl ash can be used by setting the ISO on the camera 1
2
/
3
f stop higher than the ISO set on the
digital back; for example, to ISO 160 for an ISO 50 setting on the digital back. Evaluate the
results on the histogram. When dedicated fl ash is used with H3D camera models the letter D
appears in the fl ash menu on the LCD display and the camera automatically makes the adjust-
ment for the different refl ectance value of the digital sensor.
Rather than compensating for the digital sensor, some professionals have found that the
automatic setting on the fl ash unit works beautifully. In this case the sensor in the fl ash unit
determines the length of the fl ash duration. Set the aperture on the lens. Set the fl ash to auto-
matic and for the aperture set on the lens. When changing the lens aperture, you naturally
need to change the aperture setting on the fl ash also, something that is unnecessary in dedi-
cated use.
FLASH PHOTOGRAPHY WITH H CAMERA MODELS
Flash Units
The eye-level viewfi nder of the H camera is equipped with a built-in fl ash unit (Figure 18-4)
with a guide number of 12 (for meters) or 40 (when distances are measured in feet) good
enough for family pictures indoors or as a fi ll light outdoors. The fl ash illuminates an area
within a 56-degree angle horizontally and 44 degrees vertically, producing even illumination
with lenses 80 mm and longer. The unit works in dedicated fashion with the light measured
from a 40 mm center area on the image plane.
Other shoe mount units can be mounted on the fl ash shoe. To work in dedicated fashion,
they must be specially designed for the H camera. Currently, only fl ash units compatible with
the SCA3002 system from Metz can be used and are used in combination with the Hasselblad
SCA3902 adapter made specifi cally for the H camera. Do not use fl ash units dedicated to
other cameras as damage can occur either to the camera or to the fl ash. You can identify a
dedicated fl ash by having more than one contact pin at the bottom of the fl ash shoe. With
handle mount fl ash units in the SCA3002 system, attach the control unit from the fl ash to
the Hasselblad SCA3902 adapter, which is mounted to the viewfi nder hot shoe. As usual, fl ash
units used in dedicated fashion are set to TTL.
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