[Culture]

Will a yongnuo flash work it has been described in this video with the Acon R930. You get the concept between 2-7 min mark.

You Tube

You Tube

[rawr]

Will a yongnuo flash work it has been described in this video with the Acon R930.

Probably yes. I haven't experimented with a non-HSS flash though.

But since all he seems to be doing is triggering a manual flash at full-power, whilst shooting at faster than the default sync speed, any old radio trigger that mounts on your hot shoe could do the job. Trial and error required.

[W.j.christy]

What he is doing is not really true high speed sync. HSS requires a communication between the flash and the camera to ensure a properly lit photo.

Please someone correct me if I am wrong, but how a flash adjusts the amount of light for a given exposure is by the duration of the light from the flash. The higher the power longer the duration of the light pulse, (this is for nikon but you get the idea How does the power of a flash relate to the duration of the flash pulse? - Photography Stack Exchange)

Most likely what is happening is that at 1/8000 of a second at full power the flash duration is triggered at just the right moment and last for along as the shutter is open to be capable of lighting the scene in the video. However, as it is not a controlled pulse of light, meaning that the Tx Rx and flash are not talking the HSS TTL language and therefore the flash may not pulse for the entirety of the shot.

How HSS is supposed to work is the camera relays a shutter speed and power level to the TX which sends it to the Rx who then tells the flash ok you need to pulse for x amount of time at x power to light this scene. Therefore instead of illuminating the scene with a single flash pulse (If we go back the numbers at the site above ) with a single pulse duration at 1/1 power for 1/1000s the camera tells the flash ok you need to pulse 4 times once the shutter is released at 1/4 power to get this scene right (this is an example only I truthfully don't have actual numbers). To do this, the camera, the flash, and the Tx and Rx must all speak the same language which is some form of TTL.

Interestingly the cactus flash V6II have HSS capabilities but the last I checked they don't support P-TTL even though some form of P-TTL is required (or so i think) to get HSS, ( again someone correct me if i am wrong)

In any case, could this occur with the ACON 930's? Sure. Is it likely that it will occur? Probably not as I am willing to bet its very system Dependant. It would be a neat experiment for someone with those flashes to try...

@Mcgregni is the local strobe expert on the forum and has a fantastic book that may have a better explanation of what is happening and why. I know mine is very basic and may not be 100% correct.... Hopefully he will way in.

[Culture]

Probably yes. I haven't experimented with a non-HSS flash though.

But since all he seems to be doing is triggering a manual flash at full-power, whilst shooting at faster than the default sync speed, any old radio trigger that mounts on your hot shoe could do the job. Trial and error required.

I dont think it is possible to use just any trigger. I dont know how the old radio triggers work.
With regular manual triggers, I dont even think the flash will go off if you go below 180s.
I am guessing hss triggers allow you go beyond this?

[W.j.christy]

I dont think it is possible to use just any trigger. I dont know how the old radio triggers work.
With regular manual triggers, I dont even think the flash will go off if you go below 180s.
I am guessing hss triggers allow you go beyond this?

This is where the video gets sketchy and the system dependencies come into play. I know when I mount an AF540FGZ to the Acon R930 transmitter it will not fire above 1/180 when the flash is set to a mode other than HSS.

However, the flash will fire at speeds below 1/180s with the Acons and with other systems as well. HSS is not need to go below the 1/180's mark. It is when trying to exceed it.

[rawr]

His technique seems to just rely on the fact that at full-power, the flash duration is long enough to allow a faster than sync shutter speed to work (under some circumstances). Same as using continuous lighting, essentially.

FWIW, contra to my post above, I can confirm that if you set the shutter speed above the sync speed, a manual flash and/or radio trigger is not likely to be asked by the camera to fire the flash [tested with a pair of Cactus v5's on a K-1, Metz 52 flash set to manual]. So a HSS compatible radio trigger - like the YN 622 N in the video, or the Acon R930 - will be required to convince the camera that it is OK to trigger a remote flash above sync speed.

[mcgregni]

Well I'm flattered to he referred to as an expert, but truth is there's many of us here who are are expert at aspects of flash with Pentax cameras .... It's when all the knowledge is pooled and shared that the best learning takes place!

Certainly Acon and Yongnuo will not be my field, but from the descriptions here it sounds like the technique used is 'hypersync', where a full power burst from a basic manual flash lasts long enough to cover all or most of the image frame during an exposure beyond the max sync speed. The key issue with Pentax DSLRs is that the cameras need to detect a P-TTL flash with HS mode engaged in order to provide a flash trigger signal beyond max sync. So for radio triggering we need special, rare, kinds of triggers like the Cactus V6II, Acon or Priolite ....types of trigger that simulate the presence of an HSS flash so that the trigger signal can he generated.

Hypersync can he cheaper then HSS, but the flash exposure control will be more difficult, as you will not have the option of simple power/compensation adjustments .... You have to use other flash exposure component settings.

[Culture]

I have not played around with this much as I just go my V6II. I placed the yongnuo trigger on top of the V6II.
The V6II allows the pentax camera to trigger beyond sync speed. Which is nice but there is still significant banding at the bottom.

Culture.

[W.j.christy]

I have not played around with this much as I just go my V6II. I placed the yongnuo trigger on top of the V6II.
The V6II allows the pentax camera to trigger beyond sync speed. Which is nice but there is still significant banding at the bottom.

Culture.

I take it you returned your acon 930's? what was the final straw that made you send them back?

[Class A]

The V6II allows the pentax camera to trigger beyond sync speed. Which is nice but there is still significant banding at the bottom.

A stacked trigger approach is always a bit problematic as one is getting the latency of both trigger systems and that can be enough to introduce black bars.

Having said that, this approach still works fine in many instances and it is possible that a different firmware update will remove the black bars.

Have you tried V1.1.006? That seems to be the last known good one for Pentax. From what I understand V1.1.009 was supposed to fix Pentax issues but may not have addressed all of the problems.

[Culture]

I take it you returned your acon 930's? what was the final straw that made you send them back?

You guessed right. Its on its way. I just couldn't deal with the color coding. Or the Morse code. I don't even remember my wife's phone number. How can I remember this?

I lost some money but I thought better that than years of buyers regret. I bought my yongnuo triggers years ago and I still use them on a regular basis.

I am sure the Acon is good for what it is. I just feel that the cactus gives more even though it cost more. Also I wouldnt have to buy another adapter in the future should I use a different brand flash.


PS. I really appreciated your help. Thanks.

Culture.

---------- Post added 03-05-17 at 08:39 ----------

A stacked trigger approach is always a bit problematic as one is getting the latency of both trigger systems and that can be enough to introduce black bars.

Having said that, this approach still works fine in many instances and it is possible that a different firmware update will remove the black bars.

Have you tried V1.1.006? That seems to be the last known good one for Pentax. From what I understand V1.1.009 was supposed to fix Pentax issues but may not have addressed all of the problems.

The triggers came with V1.1.006. And I read somewhere that that was the most stable version. So I have not updated it.

I removed the Yongnuo triggers and mounted the flash directly to the Cactus. I figured it should be able to trigger the YN560II. Still banding using power sync mode.

What is this manual flash option in the flash setup. Will the RF60 be that manual flash being talked about?

Culture.

[clackers]

I removed the Yongnuo triggers and mounted the flash directly to the Cactus. I figured it should be able to trigger the YN560II. Still banding using power sync mode..

Power sync is just firing full power and trying to arrange it to sustain as much as possible throughout the shutter exposure (you can try to add delay to the triggering time). Banding/gradients are always a possibility.

HSS is even exposure over the frame. The YN 568 can do it.

[Class A]

The triggers came with V1.1.006. And I read somewhere that that was the most stable version. So I have not updated it.

Good.

I think even V1.1.009 isn't as good as V1.1.006 was (as far as Pentax is concerned). Hopefully, they'll keep working on getting Pentax support back at 100%.

I removed the Yongnuo triggers and mounted the flash directly to the Cactus. I figured it should be able to trigger the YN560II. Still banding using power sync mode.

By "banding" do you mean a black bar?

Some gradation is to be expected when using Power Sync. Only when using HSS (with an HSS-capable flash) you should expect an even exposure across the frame.

Have you tried setting the flash system on the on-camera V6II to "Nikon"?
I've read that this is the best setting for the trigger stacking approach.

What is this manual flash option in the flash setup. Will the RF60 be that manual flash being talked about?

The RF60 does not require any configuration.

The "MANUAL" flash option is for flashes that are not system-dedicated, i.e., that work by centre pin triggering.

Normally, the "MANUAL" setting should also be the best choice for your trigger stacking application. For some reason (read "a bug"), however, choosing "Nikon" as the flash system is the better choice.

BTW, for Power Sync you can change the trigger timing. Press the dial and turn it at the same time while you are in the Power Sync menu option. This timing flexibility can help you to remove black bars. However, if the bar is at the bottom (and you are not using a K-1) then I don't think you'll be able to improve matters as the default timing should be "as fast as possible" and a black bar at the bottom means "too slow".

It is possible that the Yongnuo triggers are too slow. There are models that require communication with a camera to be as fast as they can. Otherwise, they'll introduce some lag (which will manifest itself as a black bar at the bottom).