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10-27-2011, 01:33 PM   #16
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QuoteOriginally posted by maxfield_photo Quote
I think HSS on my Metz 58 works at quarter power down to 1/256th power. So that would be two stops under full, maybe other units are different, but if I crank my shutter up to 1/4000th, that's a lot of ambient-light-killing power, yet the light from the flash is unaffected. I don't know, you may be right, I just got the Metz 58 a month ago, I haven't had a chance to really compare the two methods.
No, in HSS mode, the flash behaves just like a continuous light source, so any increase in shutter speed will just eat power from it...
After all, once the flash hits its maximum power in HSS mode, doubling the shutter speed will halve the amount of light provided by the HSS flash (the traveling slit is half the size it was!).
So at 1/4000th, your Metz 58 will mainly illuminate the shutter itself, and the amount of light actually hitting the sensor will be very small.

Some flash manufacturers provide the maximum GN delivered at given shutter speeds, and doing the math, you can conclude that using a ND filter eats less power than using HSS... See the last page of the Sigma 610 Super manual.

Quite easy to understand, as they both behave the same way once you passed the first step (adding a one-stop ND filter will give you exactly the same results on ambient and flash as doubling the shutter speed in HSS), but in HSS mode, the flash will lose some power by firing slightly before and after the exposure, and because of the electronic constraints caused by the sinusoidal wave modulation of the flash output.

11-01-2011, 04:29 PM   #17
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QuoteOriginally posted by dlacouture Quote
Some flash manufacturers provide the maximum GN delivered at given shutter speeds, and doing the math, you can conclude that using a ND filter eats less power than using HSS... See the last page of the Sigma 610 Super manual.
Roughly, each halving of the flash time in HSS "eats" one stop of flash output. This makes complete sense, if you think about it, as the HSS output is effectively a continuous light.
11-01-2011, 05:05 PM   #18
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If you want to try to use HSS with a mono light you'll need to find one that has a very long flash duration.
Einsteins are very fast so all you'll get is a small slit of light as the two shutter planes pass by the sensor.
You need a long flash T1 duration or a significantly bright T5 duration, such that the entire sensor is somewhat evenly lift for the 1/180 sync speed for this to even remotely work.
Now you just need to figure out how to talk PTTL such that you can fire the non-PTTL flash.

I know Paul C Buff has a lot of questions on the Alien Bees forum site about this. They have no plans to make their strobes multi-fire to properly support HSS.

And Sadly, Pentax doesn't seem to have any plans to make their cameras flash-capable above their sync speed.

Best option, make a rig like Joe McNally and tie a dozen af-540fgz flashes together all using HSS. :-) :-) :-)
You might get decent results as long as your not trying to over power the desert sun.
12-12-2011, 12:20 PM   #19
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Wireless HSS workaround with full power

See here:

Re: Russell, do you know if 530superDG....: Pentax SLR Talk Forum: Digital Photography Review

Basically, stick your HSS-capable flash on camera. Set your external Metz 58 or 48 flash for "Slave, servo mode" at full power (this will allow this flash to trigger when it sees the on-camera flash's pre-flash, but not until the main exposure). Shoot at faster than 1/180 sync speed!

I've tried this and verified up to 1/4000 with a K5 and Metz 48 and 58 units. Less than full power doesn't work though, but if you're trying to overpower full sun, you're likely shooting full power anyway and you can just vary the output by distance to subject. Just have to make sure the sensor on the off-camera flash can properly "see" the HSS signal (which can be troublesome with this sort of line-of-sight technique in bright sun, so you may need to shield the sensor; just turning it away from the sun seems to work fine).

Wireless HSS at full power. On a Pentax. Awesome.

12-12-2011, 12:23 PM   #20
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That's very good information. I will definitely give this a shot.
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