[maxfield_photo]

I want 10% of the royalties

[Toni999]

I just received my second pentax 540 unit and put it in pttl,slave, and it does not allow me to switch sync to hss. The master is in hss. Will both be in hss now or what do I need to do?

[mcgregni]

For Pentax optical wireless HSS, only the control (on-camera) flash needs to be in HS sync mode. The slave will be told the mode during the pre-flash passing information.

[awaldram]

Not to nitpick, but this is only true in a certain sense.

If "HSS" means to you "Camera makes shutter speeds above the sync-speed available when using flash" then your statement is correct.

If "HSS" means "Light source produces a burst of pulses that approximate continuous light in order to support shutter speeds beyond the sync-speed" then it is not a subfunction of P-TTL, as my workaround demonstrates.

HSS to me means High Speed Sync

The operative word being 'Sync' i.e the flash starts firing when shutter A starts travelling and stop as shutter B finishes maintaining a constant output during that period

Any method that achieves constant artificial lighting by being available for longer than the shutter is open is unmetered environmental lighting which means you'll be using trial and error to get the exposure correct.

...with respect to TTL functionality.

There are a lot of other triggers that are brand-agnostic with respect to triggering and some of them are multi-brand compatible when it comes to remote power control.

Agreed and only for cameras capable of optical pre flash TTL and TTL

[mcgregni]

I see 'HS Sync' as a Pentax specific, automatic flash control function .... (on the Pentax flashes display we see 'HS' when activated .... On a Nikon flash you see 'FP').

As such this function automatically provides a measured, continuous light output beyond the X-speed, and this requires lens coupling, aperture and ISO information. So it is a sub-feature of P-TTL,

Now, in order to avoid confusion (which we often see here both in relation to the actual terminology as well as the actual techniques) we should probably avoid using the specific term HSS for other ' workaround' approaches and spell out more exactly what they involve in their descriptions.

[Class A]

HSS to me means High Speed Sync

The operative word being 'Sync'...

I understand where you are coming from but the "sync" aspect of HSS flash lighting is just one aspect, and not even the most important, AFAIC.

You can use the standard trigger signal up to about 1/2000s (on my K-5 II) before you see a black bar appearing at the bottom of the frame. No special sync required until then.

The most important aspect of HSS flash lighting is that the duration of the light is extended to at least 1/180s. Even with a P-TTL HSS supported sync signal, you won't get any usable pictures if the flash duration is shorter than that (which it is for the vast majority of power levels).

Hence, AFAIC, the most important aspect of any HSS technology is the increase in flash duration. As the latter is possible outside P-TTL (and different syncing isn't required up to 1/2000s + there are workarounds for even higher speeds), I don't regard "HSS" as a subfeature of P-TTL.

Any method that achieves constant artificial lighting by being available for longer than the shutter is open is unmetered environmental lighting which means you'll be using trial and error to get the exposure correct.

Well, you could use a light meter, if you wanted to.

In any event, automatic exposure support and high shutter-speed flash photography are orthogonal topics, AFAIC.

[Class A]

Now, in order to avoid confusion (which we often see here both in relation to the actual terminology as well as the actual techniques) we should probably avoid using the specific term HSS for other ' workaround' approaches and spell out more exactly what they involve in their descriptions.

While Nikon uses "FP", I've seen "HSS" used in many more contexts than just P-TTL HSS.

I don't think you'll be able to change that so the better approach would seem to me to use "P-TTL HSS" when you want to refer to this specific package that includes automatic exposure support (but has its disadvantages as well), and let people continue to use "HSS" in the rather broad sense that it has always been used with.

[Toni999]

Obviously Pentax has integrated the HSS in PTTL. In general HSS has nothing to do with TTL and is implemented in manual mode in other brands.

[awaldram]

Obviously Pentax has integrated the HSS in PTTL. In general HSS has nothing to do with TTL and is implemented in manual mode in other brands.

Actually HSS is part of PTTL

To get HSS to work you need to talk to the flash units this is done using the PTTL protocol (for pentax) so needs it.

For all manafcaturers

The camera mode is something separate and yes for HSS to work you do not need the receiver (flash) to be in preflash-ttl mode but it does need to be a Preflash-ttl capable flash unit to understand what it being asked to do.

Nikon are pretty succinct in their description - which seems to cover preflash HSS and the workaround mentioned here fro manual flashes.

What is FP High Speed Sync and what are its benefits?


FP (focal plane) High Speed Sync is a feature on several Nikon speedlights allowing flash synchronization at very high shutter speeds (up to 1/4000 sec.). This feature is useful when taking portraits with flash outdoors and in other situations requiring a wide aperture in bright light. With a non-iTTL camera FP High Speed Sync is non-TTL and is available in manual exposure mode only. iTTL compatible camera cameras have an "Auto FP" mode which allows the camera to control the output of the flash, even at faster shutter speeds.

This indicates just how much more mature Nikon n CLS is compared to Canon or Pentax systems, and indeed indicates Nikon had two way communication predating TTL.

[Class A]

... and indeed indicates Nikon had two way communication predating TTL

I don't see why (FP) HSS would require two-way communication.

AFAIC, it is just another sync mode, just like S-, M-, F-, and X-sync are different types of sync modes with various pre-sync timings.

HSS just requires a slight advance trigger so that the light is already available when the shutter opens. Since the illumination time is always the same (independently of shutter speed), there is no need for another "stop" signal.

Rear-curtain sync could also just be realised via simple one-way communication.

Seems to me that Pentax tied these features to P-TTL in order to make their flashes more attractive compared to non-dedicated alternatives. Canon has been known to introduce similar artificial limitations so that users have to buy their more expensive flashes instead of getting along with their basic Canon flashes.

[photokaybrown]

Sounds like your RF60 is not freaking out then, it's just responding to the V6s (which may be freaking out) if when you turn off the V6s the RF60 stops flashing.



Two things to note here, most importantly, the RX unit, not the TX, should be connected to the camera via the audio cable (perhaps this was a typo?) The TX unit should be held in your hand, it is your "starter pistol" if you will, which starts the race between your camera and the flash, which you've rigged to give your camera a head start (by setting a delay on the RF60).

The other thing is the V6s allow for focus-on-halfpress functionality. This feature allows you to set up a remote camera on a tripod, and focus it remotely with a V6 before it takes the photo. However, if the camera is not confident that it has achieved focus, it may try to do so before it will accept a command to fire. There should be a command in the custom menu of your camera to disable this called AF-S Setting (it's #15 on my K3). Setting that to "release-priority" will allow the camera to fire regardless of whether or not it thinks the subject is in focus. Be careful though, this option prevents a lot of out of focus shots, so use it at your own risk. Setting the lens or the camera body to manual focus will also you to fire at any time.

I may have to use this method for my newly purchased AF540FGZ since I can't get i t to do HSS wirelessly.

[maxfield_photo]

I may have to use this method for my newly purchased AF540FGZ since I can't get i t to do HSS wirelessly.

It may work with an AF540, but I am a little doubtful. The RF60 flashguns have "Sympathetic HSS" mode, which functions a lot like real HSS mode but the power level is manually predetermined by the user. The AF540 on the other hand uses real HSS mode, which is to say pTTL based. Normally an off-camera AF540 relies on a preflash signal from an on-camera unit to tell it when to begin strobing, and how much power to use to achieve a proper exposure. It needs those two pieces of information to know what to do - when, and how much. The "starter pistol method" does provide a sync signal to tell it the 'when' part, but there is no preflash to tell it how much power to use. It's possible that the AF540 might just fire at full power in HSS mode which is, 95% of the time, what you want anyway (and the other 5% of the time you can compensate for with aperture or ISO), but my guess is it won't fire at all. I don't own a 540 to test that hypothesis. Maybe someone else can verify.

As a side note, I believe in order to get the AF540 into off-camera slave mode, you will need to do the following: 1)With the flash off and the camera on, attach it to the hotshoe of the camera. 2)Turn the flash on, and slide the sync switch to HSS. 3) Push the MCS button until the word slave appears in the top right corner of the LCD. 4) Half-press the shutter button on the camera to "register" the flash. I would recommend leaving it on channel 1 unless you are shooting an event with another Pentax user. 5) With the flash still on, remove it from the hotshoe, attach it to a Cactus V6 with the correct delay set, and position it where you want it in the lighting setup. Repeat these steps for any other Pentax flashes you want to use in your setup.

[mcgregni]

I don't think that would work like that .... As I understand it the Cactus in receiver mode will provide a trigger signal and manual power output only. The HSS mode instruction is only sent via a P-TTL optical pre-flash ....(there is no need to set HS sync mode on the slave). I can't see how the AF540 will fire an HSS burst without the optical pre-flash instruction .... ?

[Class A]

It may work with an AF540, but I am a little doubtful.

I can't see how the AF540 will fire an HSS burst without the optical pre-flash instruction .... ?

You are both correct in assuming that the AF540FGZ will not work as an HSS flash on an off-camera V6 receiver. The V6 only supports remote power control, not system-dedicated features like HSS or second-curtain sync for off-camera flashes.

However, if one sets the AF540FGZ to full power then that's almost the same as using it in HSS mode. One obviously only has one power level available and the contribution to the exposure will be a bit graduated, but one can still use the AF540FGZ as a contributer to high-speed shutter photography in this manner.

This approach is often referred to as the "HyperSync" approach.

As a side note, I believe in order to get the AF540 into off-camera slave mode...

Just clarifying that slave mode wouldn't be required when using radio triggering.

The procedure you described is only necessary if one wants to enable optical triggering.

[mcgregni]

Yes, that's for SL1 mode wireless optical ...( when the camera is looking after flash metering and communicating power and mode settings to the slave via an on-camera control flash) .

For SL2 ('dumb slave') mode then again, no need to have a wireless channel set.