need help calculating aperture with speedlights

[BrianShaw]

... I do use them when the flash is in auto mode just to check if the auto feature is working correctly.

If you don't mind me asking, how? Do you set the auto setting, say, to f/8 and then measure to see if the flash meter says something around f/8?

 

[jstraw]

i have one i use with my lumedyne 244 ...
output can be full 400WS or 2ws or trimmed in between.
its pretty useful ... and i wish everything i used had this feature ..

I can see how that would be useful. It's certainly uncommon. I've never encountered anything like it.