[beholder3]

That's true for P-TTL HSS, but not in general.

It is true in general. High-Speed-Sync "HSS" is a defined thing within all x-TTL systems. It can not exist without TTL.

see:

HSS requires special timing information from the camera. This information is communicated through the TTL pins of a camera's hot shoe. A normal studio flash cannot perform the light pulse technique.

Then there are a number of makeshift workarounds to simply achieve "Supersync" speeds. One manufacturer (pocketwizard) has copyright on the term "Hypersync" as a brand for "Supersync".

There is a big difference between a two way TTL communication using HSS for easy automatic exposure (which is a convenience feature like autofocus) or a basic ability to fire a flash beyond sync speeds (Supersync) which still needs full manual control of its power output.

Both have their use in different scenarios.

The typical camera user with a single pocket flash unit will value the ease of use of a TTL flash system (that is why it's everywhere in the better flashes).

The few people who use multi (studio) strobe setups who define the individual power output personally anyway use Supersync (plus the ones who don't have the money for better pocket flashes).

Who ever wants to know something about this topic should read this here:
Understanding HyperSync and High Speed Sync - PocketWizard Wiki

Anyhow the acon R930 is currently the most advanced flash transceiver system we can get for the Pentax system. No other system support PTTL (and HSS) directly by RF (the aocatec approach is much too homemade).

Now we can use a pocket flash 100% like it was sitting on the camera body with full PTTL features, even if the flash is behind the next corner or sitting in a light former blocking optical signals.

Kudos to the guys in China who made this work.

[Class A]

It is true in general. High-Speed-Sync "HSS" is a defined thing within all x-TTL systems

You can deny this but

1. People and some companies use "HSS" in a broader sense, including any use of flash beyond the sync-speed. You can argue that this is "wrong" and I'd agree, but it happens. It simply isn't true that if you read "HSS" that it always means TTL-based HSS.
2. It makes sense to refer to "HSS" flash photography as long as the flash issues a very fast series of light bursts in order to approximate a continuous light output. It is not essential, that the correct timing is achieved via a TTL protocol. For instance, with a Cactus V6 I can release the camera and the flashes at the "same" time (the flashes need to be delayed) and thus achieve HSS light (i.e., practically continuous) output without involving any expensive P-TTL equipment.

So yes, technically in the context of using a Pentax DSLR, "HSS" only refers to "P-TTL HSS", but you cannot depend on every occurrence of "HSS" to mean "TTL-based HSS" and while some of the deviations are examples for loose talk (as they really mean HyperSync/Supersync), others are valid as they still refer to the correct light output technology but simply do not require TTL.

It can not exist without TTL.

That is only true with a narrow definition of "HSS".

If you include other forms of triggering the same light output then "HSS"-lighting is possible without TTL.
For instance, you can trigger many non-TTL RF60 in HSS mode by just using one P-TTL on-camera flash, or by triggering the camera and flashes remotely at the "same" time (thus not using any P-TTL equipment at all).

Then there are a number of makeshift workarounds to simply achieve "Supersync" speeds.

SyperSync/HyperSync is not a workaround, it is a different technique.

Many lights are not capable of generating a fast series of bursts that approximate continuous light (HSS style light output). However, they can "burn" long enough with just one pulse to still illuminate the full frame.

Neither lighting technique is a replacement for the other, they are just two different ways to take the shutter speed beyond the sync speed and still get the whole frame illuminated. Since they are tied to the technology of lights, it makes sense to distinguish them independently of how the triggering works. Hence my argument to not use "HSS" only in conjunction with a certain triggering technology.

Do you have a suggestion how to call "HSS"-style light output to distinguish it from "SuperSync"-style light output without implying a triggering approach?

The typical camera user with a single pocket flash unit will value the ease of use of a TTL flash system (that is why it's everywhere in the better flashes).

Whether they are "better" flashes, is debatable.

They just support exposure automation. A point and shoot camera with exposure automation is not necessarily better than a manual camera. Likewise, a manual flash could be better in terms of recycling rate, power output, additional features, and value for money.

The few people who use multi (studio) strobe setups who define the individual power output personally anyway use Supersync (plus the ones who don't have the money for better pocket flashes).

There are also many who have the money for more expensive TTL solutions but simply don't want to waste it on (automatic exposure) functionality they don't need. These people know how to get the correct flash power very quickly and enjoy the much more predictable and consistent output of manual flashes instead of fighting the quirks of automatic exposure. I trust you know David Hobby (running "The Strobist") and his philosophy on flash photography.

Anyhow the acon R930 is currently the most advanced flash transceiver system we can get for the Pentax system.

I dispute "most advanced".

1. The Aokatec triggers achieve the same functionality and just require a more clunky setup. We probably agree that they are bulky and cumbersome to set up, but in terms of functionality they are just as "advanced".
2. The P-TTL support added by Aokatec and Acon triggers is not very useful for multiple off-camera flashes. The P-TTL system is simply too outdated to be useful for any but the most simple lighting setups. The nice upshot of getting P-TTL support is HSS triggering and second-curtain sync triggering.
3. There is other advanced functionality, that is not supported by the Acon triggers. For instance, the Cactus V6 support remote control of power of individual flashes and/or the whole group, they support being triggered optically, they allow delays to be configured to achieve the second-curtain sync effect, or staged multi-strobing, or releasing cameras and flashes at the "same" time, or cameras at different times ("bullet time effect"), etc. They furthermore support a relay mode that allows you to configure the flash power and remote release the camera with one and the same trigger. They support group cycling which can be used to swap between normal and background lighting quickly ("mask generation") or alternate between up to four different flashes to achieve virtually zero recycling time, etc. Moreover they support a mode in which different flashes are calibrated to achieve the same absolute power output and can make older TTL flashes emit extremely short flash pulses (shorter than they can do natively).

So no, for some reasonable definition of "advanced" I don't think the Acon triggers are the most advanced.

[Hart-Worx]

Have you not noticed the PrioLite system before?

Also, if you are prepared to use a semi-automatic approach (requires using a manually entered delay time), the Cactus V6 has been supporting HSS / HyperSync for a long time.

Note that studio strobes typically will only support HyperSync (implying a gradation over the frame) as opposed to true HSS (that mimics continuous light). This raises questions as to how suitable the Acon trigger is for studio strobe applications involving shutter speeds above the sync-speed.

i know these priolite sets. but this is simply not working for me ... i have a LOT of Hensel Equipments and they dont offer a comparable product range.

So you say that i should get the Cactus triggers? There I can set the delay?

[Class A]

i know these priolite sets. but this is simply not working for me ... i have a LOT of Hensel Equipments and they dont offer a comparable product range.

I'm not sure what exactly is not working for you.

You can use your Hensel modifiers on the PrioLite lights (the CEO of PrioLite used to work for Hensel).

So you say that i should get the Cactus triggers? There I can set the delay?

The Cactus V6 certainly allows you to configure delays at will (whether it is used as a transmitter or receiver).

You'd be able to fine-tune results to your liking and the only downside I see is that you have to set the delay manually and that the optimal delay value may depend on the aperture value (with a small apertue, the camera needs a tiny amount longer to stop down the lens before it can start the exposure). With my K-5 II, however, I found one delay value that worked for all apertures to my satisfaction.

Whether the V6 are right for you depends on how important it is for you to have a plug and play solution. The Acons may do the trick (someone else successfully used them for hypersyncing). But unless a firmware upgrade will come, you won't be able to fine-tune the timing and you won't have all the other extra V6 functionality I listed in my earlier post.

Keep in mind that if the 645 stops generating a trigger signal beyound the sync-speed (like any other Pentax DSLR) then you either need an HSS-capable P-TTL flash on camera to get an optical trigger signal for the V6, or you need an extra V6 for triggering camera and lights at the "same" time. This means you'd also have to get a shutter release cable (cheap 3.5mm to 2.5mm stereo audio cable) and would have to initiate shots with the remote V6 rather than the shutter release button.

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Last edited by Class A; 10-27-2015 at 03:33 PM.

[Class A]

BTW, Cactus are working on incorporating native HSS triggering (that would obviate the need for manual delay values and the use of an HSS P-TTL flash for triggering, or the use of a remote V6 to trigger both camera and lights at the "same" time).

Cactus have always maintained backward-compatibility whenever possible, so I expect any new product to be compatible with the V6 to the extent possible.

[mattb123]

BTW, Cactus are working on incorporating native HSS triggering (that would obviate the need for manual delay values and the use of an HSS P-TTL flash for triggering, or the use of a remote V6 to trigger both camera and lights at the "same" time).

Cactus have always maintained backward-compatibility whenever possible, so I expect any new product to be compatible with the V6 to the extent possible.

Looking forward to that!

[awaldram]

I dispute "most advanced".

1. The Aokatec triggers achieve the same functionality and just require a more clunky setup. We probably agree that they are bulky and cumbersome to set up, but in terms of functionality they are just as "advanced".
2. The P-TTL support added by Aokatec and Acon triggers is not very useful for multiple off-camera flashes. The P-TTL system is simply too outdated to be useful for any but the most simple lighting setups. The nice upshot of getting P-TTL support is HSS triggering and second-curtain sync triggering.
3. There is other advanced functionality, that is not supported by the Acon triggers. For instance, the Cactus V6 support remote control of power of individual flashes and/or the whole group, they support being triggered optically, they allow delays to be configured to achieve the second-curtain sync effect, or staged multi-strobing, or releasing cameras and flashes at the "same" time, or cameras at different times ("bullet time effect"), etc. They furthermore support a relay mode that allows you to configure the flash power and remote release the camera with one and the same trigger. They support group cycling which can be used to swap between normal and background lighting quickly ("mask generation") or alternate between up to four different flashes to achieve virtually zero recycling time, etc. Moreover they support a mode in which different flashes are calibrated to achieve the same absolute power output and can make older TTL flashes emit extremely short flash pulses (shorter than they can do natively).

So no, for some reasonable definition of "advanced" I don't think the Acon triggers are the most advanced.

I would argue the Aokatec is a more elegant remote xTTL flash solution
It may be more cumbersome to set up and less reliable (optical RX could conceivably move during shoot)
But I can pick up a Canon and use my Aolatecs for RF triggering, Pick up my Olympus or my Sony a or my Nikon and do the same all without any modification to the triggers as purchased.
That is a very advanced level of functionality for an inherently brand locked protocol.!

The Aokatecs also operate very well in multi flash RX setup and can themselves drive two flashes each (grouping) by the addition of a cheap Optical feed

The Acom can only control 1:1 flash to Rx'r and there is no infication they support anything but 1:1 RX to TX

I have happily used 1:2 TX to RX with 1:2 flashes attached giving 1:4 TX to flash with 2 goups

The Cactus V6 can also be easily used using pass through to give great mix manul/P-ttl with Cactus V6's and Aokatecs

So in summary if my suspicions of the Acom functionality is correct it ai just a very expensive wireless P-ttl cable substituent.

Whereas both Cactus,Aokatec and every other RF flash trigger (I know) deliver fan out for multiple flash triggering.

P-ttl obviously uses light+flash ID for the back channel

Can the Acom respond from the associated ID and direct the the correct Rx'r

This isn't a problem for Aokatec as it carries full feed from the camera to each flash and the flash decodes which data is its own.

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Last edited by awaldram; 10-29-2015 at 05:28 AM.

[patarok]

Sounds great! I'd really like to be able to do remote wireless RF HSS sometimes.
Unfortunately my P-TTL flashes are a Sigma (not listed) and the Metz 58 AF-2 which seems to have no green in its row on that compatibility chart. I wonder why that is when all those other Metz flashes seem to be compatible.

AFAIK there is a problem with the Metz 58 AF-2 communication in general. Google Strobist+P-TTL+Guide, when found look for info on the interoperability of different flashes.
Maybe he does not know everything that works... (my Sigma EF 610 DG Super does work very well in combo with the 540FGZ) but he dedicatedly reported a problem with SOME Metz Flash...(sry i dunno which one but i guess it was the 58...) -v-o-v-

[patarok]

any progress on a user patchable firmware to fine-tune the sync delay?

i would like to hear something.

[Alizarine]

Hope they ship worldwide. Great to hear some Pentax following from other countries picking up where OEM can't make some!

[mattb123]

AFAIK there is a problem with the Metz 58 AF-2 communication in general. Google Strobist+P-TTL+Guide, when found look for info on the interoperability of different flashes.
Maybe he does not know everything that works... (my Sigma EF 610 DG Super does work very well in combo with the 540FGZ) but he dedicatedly reported a problem with SOME Metz Flash...(sry i dunno which one but i guess it was the 58...) -v-o-v-

I emailed them about it and was told they have the Metz issue solved so I ordered a pair!
Haven't gotten them yet...

[Andrzej Makuch]

Hello, I read all about controlling the flash, because so far I have had K-5 and now I k-3II and Metz 48AF-1. With K-5 could control the lamp Metz 48AF-1 firmware update which also has HSS and modeling flash.
1. The Pentax K-3 HSS works with feet but altogether I do not have a remote control pTTL, even what was in the K-5 with built-in Lights- because K-3II this lamp is not there. Saddens me very much that PTTL and HSS that could help in this situation thanks to Acon - for the camera and flash is not working. (?)
2. However, if the act - whether the transmitter can be both a receiver to another transmitter? They are sold in pairs and 2 pairs of transmitter - receiver could've been interesting in buying if one transmitter can also operate as a receiver - we have 1 transmitter and 3 receivers for 3 lamps, one of which is the "supplementary" transmitter.
I hope you have understood me.
Regards.

[thomaskplee]

I just got a pair of Acon 930 today, and tested it on my 645Z and Metz 64 AF-1 flash and it works well for HSS by 1/4000, so it seems is a workable solution for the Pentax med format camera for HSS remote control. However, it does not come with any user manual, and I found the Acon website's link for downloading user manual does not work any more, while the company sold me the set is off for Chinese New Year holidays now, so anyone have a copy of the user manual of Acon 930 that can share with me? Now I can only power them on to work, but have no idea of how to change channel, or set ABCD groups. Will the Acon 930 able to have multi receivers for grouping?

Regards

[beholder3]

Now I can only power them on to work, but have no idea of how to change channel, or set ABCD groups. Will the Acon 930 able to have multi receivers for grouping?

I think they are only for controlling a single flash remotely. On my unit I can not set anything else (but that was what I wanted it for).

But basically you can set other PTTL-HSS flashes to slave mode.

Consider the acons as a cable without a cable.

[Andrzej Makuch]

Raczej pojedynczą grupą lamp... choć nie wykluczam że ktoś znający Chiński mógłby uruchomić i pozostałe grupy.