Pierwsze kroki z portretem prosze o wskazowki

[micles]

Hmm, chyba znalazłem :

The first limitation to be aware of is that you lose about one stop of flash power when you switch to high speed sync. This is usually a small price to pay for the advantages of high shutter speed and/or wide-open aperture.

In addition, if you look at the output power charts in the flash manual, you'll see that for every stop increase in shutter speed, you lose another stop of flash power. Some people incorrectly conclude from this that the flash output is so small at high shutter speeds that it must be useless. That's a mistake.

I jeszcze tutaj :

But when you study the numbers for FP Flash, the first thing you realize is that the guide number is cut in half each time the shutter speed is quadrupled. So your effective distance doesn’t change as you shift exposure settings in a given ambient light situation, matching faster shutter speeds with wider apertures. This makes sense when you think of FP Flash as a continuous light source. For example:
Using the guide numbers for FP Flash and 105mm zoom :
1/250 and f/10 gives you 2.5 meters (25.0/10)
1/1000 and f/5 gives you 2.5 meters (12.5/5)
1/4000 and f/2.5 gives you 2.5 meters (6.3/2.5)

Czyli przy HSS nie zyskujemy na świetle, a tylko i wyłącznie na tym, że możemy sobie proporcjonalnie otworzyć przesłonę i skrócić czas ekspozycji.