Originally posted by Anvh just use an ND filter.
But ND filter or ISO does not solve the reason why we want a faster shutter speed.
We want faster shutterspeed to low the ambient light while keeping the flash light at the same level.
If you use lower ISO or a ND filter then you're also cutting the flash light so the balance remain the same.
but is the 1/3 stop really relevant? that is the whole focus of the discussion. you seem to be focused on the fact that everything else is fixed except shutter speed. you can increase clearly the flash intensity, and lower the ISO to get to the same balance so it does not really matter in that case. After all we are talking about the relative contribution of ambient light to flash. I will assume for artistic reasons the aperture setting is off limits, therefore, in terms of degrees of freedom, while leaving aperture where it is, we have the following
- iso
- flash intensity/duration
- sync speed
- ND filter
- high speed sync
you can;t be at the limit of all of these unless you are shooting wide open with a very fast lens, in daylight, and at a distance that is so far from the subject that you cannot reach with your flash in high speed sync mode, and therefore, probably wasting your time any way. go back to the beginning, how can 1/3 stop be a sever disadvantage relative to the competition.
the truth is, it does not matter, other than in specmanship. it is somewhat similar to arguing whether a 6, 10, 14, or 16 mp will produce a better 4x6 print, when in reality all you need is about 2 MP.
the other points such as increasing trailing curtain sync to 1/180 as opposed to 1/90, and getting a shorter duration brighter flash are much more important than arguing over 1/3 of a stop