The Sigma EF-500 flash - Light duration vs. output power
The measurements in the below table help to illustrate the amount of time that the flash is emitting light in each of its various power setting. This time is crucial when taking high speed photos.
Measurements were done with a Photo-diode, oscilloscope set to 50ohm.
| 1/1 Output power |
 |
| 1/2 Output power |  |
| 1/4 Output power |  |
| 1/8 Output power |  |
| 1/16 Output power |  |
| 1/32 Output power |  |
| 1/64 Output power |  |
| 1/128 Output power |  |
contributed by Karsten Stroemvig (aka Lullaby)
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Comments
What is the time span?
The labels on the horizontal scales include "400 us" for
the first four, and "40.0 us" for the last four. Are those
full width of the respective plots, the half width, or what?
Re: What is the time span?
It's obviously the time per division. The author was kind enough to include cursor measurements of the pulse width as well, which you can clearly see on the right hand side.
Time Scale:
The "µs" in the "time scale" means "microseconds". The "µ" is actually the Greek symbol for the lowercase letter M, or mu.
Time Scale
The actual length of the flashpulse is given in red next to the triangle (uppercase delta) in ms (milisecond, 1/1.000 s) and µs (microsecond, 1/1.000.000 s).
To give a more comprehensive number to the photographically inclined, the last one (32.8 µs) would equal to a exposure setting of 1/30800, if I am not mistaken.
(As 1/ 0.0000328 = 30800).
Hope that helped the guys not familiar with oscilloscopes.
-D
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