1 ACCEPTED SOLUTION
The 580EX II and 600EX should be very close in flash duration.
Keep in mind that when comparing flash duration, there are 2 different flash duration time definitions in use. One is called t 0.5 and the other is t 0.1
t 0.5 is the time between the moment where the flash intensity curve starts to exceed 50% of the maximum intensity point and the moment where the falling intensity curve goes underneath the 50% maximum level again.
The t 0.5 time is about 3 times shorter by definition and therefore used by most speedlite manufacturers, (e.g. Nikon and Canon) to exaggerate short flash duration.
Page 133 of the Canon 600EX Manual shows the t 0.5 duration times.
The 580EX II Manual only lists a 1/1 power t0.5 time duration of 1.2ms and that equals about 1/833 sec.
Since 580EXII and 600EX have the same Guide Numbers at identical zoom levels, I would expect them to have similar flash durations at comparable power settings.
This blog...
Flash Duration Analysis uses t0.1 times and has some test numbers that show some difference between the 580EXII and 600EX. The differences may be due to variations in individual flash units, or the testing methods, and I have seen other values quoted by other testers.
These tests below were were all done using t0.1 times..........
Actual Measured Flash Durations of Small Speedlight Strobes
speedlights.net 580EX II Flash Review
The 580EX II and 600EX should be very close in flash duration.
Keep in mind that when comparing flash duration, there are 2 different flash duration time definitions in use. One is called t 0.5 and the other is t 0.1
t 0.5 is the time between the moment where the flash intensity curve starts to exceed 50% of the maximum intensity point and the moment where the falling intensity curve goes underneath the 50% maximum level again.
The t 0.5 time is about 3 times shorter by definition and therefore used by most speedlite manufacturers, (e.g. Nikon and Canon) to exaggerate short flash duration.
Page 133 of the Canon 600EX Manual shows the t 0.5 duration times.
The 580EX II Manual only lists a 1/1 power t0.5 time duration of 1.2ms and that equals about 1/833 sec.
Since 580EXII and 600EX have the same Guide Numbers at identical zoom levels, I would expect them to have similar flash durations at comparable power settings.
This blog...
Flash Duration Analysis uses t0.1 times and has some test numbers that show some difference between the 580EXII and 600EX. The differences may be due to variations in individual flash units, or the testing methods, and I have seen other values quoted by other testers.
These tests below were were all done using t0.1 times..........
Actual Measured Flash Durations of Small Speedlight Strobes
speedlights.net 580EX II Flash Review
