User manual

78
X2D 100C
User Manual
CONTENTS
Light level at
image plane
T fully open
Maximum aperture
Stopped down
one stop with True
Exposure ON
Stopped down
one stop with True
Exposure OFF
Time
T stopped down = T fully open
(Using True Exposure)
T stopped down > T fully open
(Without True Exposure)
True Exposure is an XCD and HC/HCD lens function that allows the shutter speed to remain
unaffected when stopping down. This effect is perhaps not so commonly understood as it is
restricted specifically to integral lens shutters as opposed to focal plane shutters.
When a lens is stopped down, the effective shutter speed becomes longer, consequently
affecting the set exposure. At slow shutter speeds the effect is minimal but at faster speeds,
e.g. 1/500s, the effect becomes clearly visible. Automatic compensatory measures in speed
setting adjustments are employed.
As compensation can only be put into effect where speeds can be adjusted, this prevents
the possibility of adjusting the fastest speed. To counter this, compensatory adjustments
are therefore made to the aperture instead to retain the set exposure. This compensation
is not always required and when using flash/strobe as the main light source it is actually
undesirable because compensation will result in underexposure. Therefore, when using
flash/strobe as the main light source, disable true exposure in Main Menu > Exposure > True
Exposure on the touch display.
Download a complete explanation of this situation from www.hasselblad.com.
True Exposure Explained