51
Electronic Flash Emission
0
0.2
0.4
0.6
0.8
1
1.2
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17
Time (ms)
Output level (%x100)
Now, to understand the next component we need to remember
that a focal plane shutter (as fitted to a D-SLR) consists of two
curtains. The shutter-speed set for any given exposure denotes
the delay between the departure of the first curtain to uncover
the sensor to the incoming light, and the departure of the second
curtain to blank it off again.
At speeds up to and including the X-synchronisation speed, the
gap between the first and second curtain exactly equals the
height of the sensor’s imaging area. Thus, if we were to emit a
short burst of light at the moment that the first curtain
completely uncovers the sensor, the entire sensor area would be
able to record the flash light being reflected off the subject.
FP FLASH MODE EXPLAINED
At speeds beyond the X-synchronisation threshold, however, the
first curtain has only completed a portion of its travel before the
next curtain starts closing off the sensor. Thus if we were to
pulse the flash at any of these speeds we would only find a
To Next Page
Loading...
Need help?
General
Weight and Dimensions
