High speed sync on AF540FGZ
For HSS to function the flash needs to operate in P-TTL. When you take the flash off camera, the HSS does not function unless you use a TTL lead. If you want to use P-TTL wirelessly, the only way to do it that I know of, is the Aotek trigger.
My understanding is it's primarily due to the way HS has to work - by 'peppering' the frame with smaller bursts of light as the shutter curtain moves down the frame. The only pop-up that could do HS wireless was on the *ist-D. (Somewhere I read that the bursts of energy and resulting electrical noise on the power rails on the flash caused problems for SR - who knows!)
You can use manual camera exposure with P-TTL flash though and that does give a modicum of control
Matt
(For gallery, tips and links)
Stuart..
Looks like I could be struggling
What is the concrete challenge?
There is unfortunately no way around using a P-TTL flash connected to the camera (on the hot-shoe or using a cable), but you could use a Cactus V6 (or Cactus RF60) to optically trigger on the P-TTL flash and thus gain a radio trigger signal from the HSS flash.
You are then free to trigger as many off-camera flashes as you like. The Cactus RF60 offers an HSS sympathy mode that achieves HSS bursts for all manual levels, but you can also use pretty much any flash at full power because with most speedlites at full power the pulse is long enough to illuminate the whole frame.
Not strictly true, P-TTL is disabled when a pre-A series lens is used.
I'm not sure what you are objecting to.
Please note that my statement was made in the context of using HSS, i.e., the camera is using a shutter speed higher than 1/180s.
In such an HSS situation, the only way to obtain a trigger signal is optically from a P-TTL flash connected to the camera.
If a pre-A lens disables P-TTL then even that triggering opportunity is gone and in this case you cannot use flash beyond 1/180s at all.
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1973 posts
13 years
Manchester
Stuart..