580EX2 against 600EX more power ?

[Timothy_Bruce]

wonder if the 580 has more power ...
580EX2  58 at 105mm  and the 600EX  is 60 at 200mm.
what will the 600 have at 105mm ?
anyone know about ?

[MikeHunt]

Even though the manufacturers typically quote the maximum flash distance fully zoomed, the standard comparative test is to measure all flashguns at 35mm angle @ ISO = 100 and the old 580EX2 is rated at GN 36 at 35mm, but test results have shown it higher (see link below)

http://speedlights.net/2011/04/18/canon-speedlite-580ex-ii-flash-review/

What we really need to see from the new 600EX and 600EX-RT is the GN @ 35mm