[stevebrot]

Even more astounding news, I'm able to get TTL and HSS with the Xpro-p on my MZ-S.

The *ist (non-D) and MZ-6 should also work. All three cameras support P-TTL with HSS.


Steve

[DimC]

French distributor informed me that GODOX wont be able to deliver to their France resellers for another month

[GeneV]

No. The X1R receivers do not do cross-brand TTL. They are not like the Cactus V6II transceivers; they remain dedicated to a single system and can only do TTL in that one system. You cannot use legacy P-TTL flashes in the Godox system as anything other than manual-only slaves at this time.

Also, you'd need an X1R-P to work with a P-TTL flash, which doesn't yet exist. At this time, the X1R receivers only come in Canon, Nikon, and Sony flavors. And for a trigger to communicate TTL from a camera to a flash, the pins on the foot of the flash have to match the contacts on the hotshoe of the receiver, and both must speak the same TTL communication protocol the camera and transmitter do.

FWIW, I have not had much luck getting a Sony camera to transmit TTL flash control through an Sony X1 transmitter to a Sony X1R to a flash designed for Sony TTL. I have seen on other forums that my issue is not unique. The system is not perfect.

[inkista]

FWIW, I have not had much luck getting a Sony camera to transmit TTL flash control through an Sony X1 transmitter to a Sony X1R to a flash designed for Sony TTL. I have seen on other forums that my issue is not unique. The system is not perfect.

Yup. The X1R receivers are probably the most problematic device in the system. It's why most Godox users will switch completely over to Godox speedlights, not only for the convenience of the built-in triggers, but also for the better function. Sony users also have to deal with a TTL bug; that there's underexposure when used with aperture settings wider than f/4. None of the other systems is seeing anything similar.

However, this bug is also seen with other 3rd-party radio TTL systems (like Jinbei's), so isn't unique to Godox, and probably has something to do with how Sony's multi-interface hotshoe TTL signalling is somehow resistant to reverse-engineering.

The older flash systems, like those from Canon, Nikon, and Pentax, still use analog signals on the flash hotshoe (for backwards compatibility with film-era gear), and seem to be easier to 'crack' for companies like Godox, Yongnuo and Jinbei. The newer mirrorless systems, like Sony, Fuji, and four-thirds seem to have some form of digital signalling as well, which isn't. Sony has a TTL bug in its Godox system, while Fuji and Panasonic four-thirds gear are having HSS banding issues. There are other issues that arise from the newer mirrorless bodies having to implement certain things differently with flash, so issues like HSS banding with electronic first-curtain shutter (Sony bug), and AF-assist not working with IR signals, given that the main image sensor (which is all a mirrorless camera has to focus with has an IR/UV blocking filter over it); are just a few things that the 3rd-party flashes are having issues with and finding workarounds for (e.g., the newer AF-assist lights are LEDs). The Godox picture is not identical for all flavors.

As someone who's using Godox on Canon, Fuji, and MFT, I can categorically state that I get a lot more function out of the Canon versions than the Fuji or the MFT versions.

On top of that, Godox is low-cost Chinese gear. They really don't spend a lot of time on integration testing or corner-case testing. That's part of why the pricetags are so low (aside from making your retailer your support tier). I have a $65 TT600. It's probably the simplest flash that Godox makes in the system. All the advertised features on it work great: I have radio triggering, HSS, and remote power control. It has S1/S2 "dumb" optical slave functions. They work great. There's a MULTI mode. It works great. And if I put the thing into S1 and MULTI at the same time, the stupid thing will repeatedly fire until I turn it off. Doesn't matter how many bursts I programmed for MULTI mode. Because the later bursts in the MULTI mode are re-triggering the optical slave. No integration testing, remember? Do I plan to use it in S1+MULTI? Not really. And it's still a $65 flash that gives me HSS radio triggering. But if anybody tells you Godox is "Just like OEM gear, only cheaper," do not believe them.

So, yeah, Godox isn't a perfect system. But for most of us, it's still perfectly usable. And they can still be a good choice, because the features they do have OEM doesn't (multi-brand TTL support, bigger studio lights, built-in radio triggering, etc.) can trump the inability to use legacy flashes.

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Last edited by inkista; 11-05-2018 at 07:32 PM.

[Class A]

The older flash systems, like those from Canon, Nikon, and Pentax, still use analog signals on the flash hotshoe (for backwards compatibility with film-era gear)...

That's absolutely not true.

The Pentax hot-shoe design that supports P-TTL has a pin which is dedicated to support digital data communication. Flash power is communicated with digital codes, camera settings are communicated digitally, etc. I'm sure it is the same for modern Nikon / Canon flash protocols.

I'm not saying that there is no analogue signal support anymore, but that the analogue signals are pretty much irrelevant for modern flash protocols like P-TTL. An explanation as to why some flash protocols are better supported / reverse-engineered cannot be based on a distinction between analogue signals vs digital communication.

[awscreo]

Does anyone know if godox will release a P version of the v860 II? I wasn't able to find anything on that topic.

[stevebrot]

I'm not saying that there is no analogue signal support anymore

Yep...it depends on the flash*. Some support the legacy analogue TTL and dedication protocols for use on older cameras and some don't. Bottom line is that those protocols never apply to P-TTL.


Steve

* I believe the most recent Pentax-brand flashes to support the analog protocols were the AF360FGZ and AF540FGZ. Current product does not.

[inkista]

That's absolutely not true.

The Pentax hot-shoe design that supports P-TTL has a pin which is dedicated to support digital data communication. Flash power is communicated with digital codes, camera settings are communicated digitally, etc. I'm sure it is the same for modern Nikon / Canon flash protocols.

I'm not saying that there is no analogue signal support anymore, but that the analogue signals are pretty much irrelevant for modern flash protocols like P-TTL. An explanation as to why some flash protocols are better supported / reverse-engineered cannot be based on a distinction between analogue signals vs digital communication.

Good to know. I'd assume the fire/sync signal, however, is still analog (short from sync to ground), as that's part of the ISO standard for hotshoes. But I wasn't aware the quench pin signal was no longer relevant to power cutoff. Camera settings being done digitally makes perfect sense, and is the one part of the flash signaling protocol that doesn't seem to fully be part of the Godox communication, except for Canon users (i.e., menu communication being fully two-way only with Canon bodies).

[mcgregni]

I don't imagine a "quench" signal is relevant to digital TTL ... Remember that the main technical difference between the older and newer types of flash metering is the exact stage that the correct exposure is determined.

For P-TTL this decision is made before the exposure, pre-determined. Older film plane TTL and thyristor types determine the output during the actual exposure. This seems to me to be the single most important distinction.

[inkista]

I don't imagine a "quench" signal is relevant to digital TTL ... Remember that the main technical difference between the older and newer types of flash metering is the exact stage that the correct exposure is determined.

What I'm talking when I say analog or digital has nothing to do with how the TTL metering is done. That's definitely digital processing in the camera body. What I'm talking about is the flash hotshoe pinout. Not whether we're shooting film or digital TTL.

Remember, when you're reverse-engineering, all you have to go on is the pinout. You don't have any visibility into the internals of the design. All you can do is measure signals on the pins and make a best-guess, and test it to see if it works. Godox probably has no clue what the TTL algorithms are that anybody's using.

Flash firing is all analog signalling. It was set up that way in the ISO standard. Rails are ground. Center contact/pin is firing. The signal to fire the flash is a short from sync to ground. That cannot change without making the flash or the hotshoe non-ISO compliant, and all those manual-only single pin flashes/triggers wouldn't work any more.

A quench signal is how you turn the firing off. Remember that power is a function of time. You're not just pushing more volts/amps through to get "more power" you're leaving the flash tube turned on for longer. So power control is done with the quench signal. Use a lower power setting, send an earlier quench signal. Use a higher power setting, send a later quench signal. How and what the power is set to (via M ratio or TTL metering) is just a way of adjusting when the quench signal occurs.

First curtain/second curtain and hypersync are all about timing when the sync signal happens.

HSS is different, since that's about repeated firing for a specific duration.

But analog is easier to reverse engineer, because you eventually figure out what each pin signal is for.

Digital is harder to reverse engineer, because it can be multiple pins, it can be a sequence of signals on a single pin, and it could all just break down into just numerical codes that are interpreted as commands, which you have to decode.

I used to spend my professional life documenting register pinouts on SOC products. I have a very warped/different view of these things than most people.

[ProfessorBuzz]

I've joined the club thanks to you pioneers. My shiny new XPro-P (firmware v1.0) is working great with my Canon-footed TT685c (firmware v3.3), on a K1 and 645Z.

I haven't tested the heck out of it yet, but thought you might want the data point.

The existing TT685c firmware 3.3 seems to be fine, no need to wait for an update.

[inkista]

I've joined the club thanks to you pioneers. My shiny new XPro-P (firmware v1.0) is working great with my Canon-footed TT685c (firmware v3.3), on a K1 and 645Z.

I haven't tested the heck out of it yet, but thought you might want the data point.

The existing TT685c firmware 3.3 seems to be fine, no need to wait for an update.

This is good to hear! I'd suspected as much from the TT600's ability to do HSS. I'm assuming the only thing that won't work without a specific Pentax firmware update for the TT685 flashes is TTL. HSS and remote power control are probably fine.

Out of curiosity, what does it say on the LCD of the TT685-C to indicate it's in Pentax mode?

[Class A]

I'd assume the fire/sync signal, however, is still analog (short from sync to ground), as that's part of the ISO standard for hotshoes.

Yes, connecting the centre pin against ground is the standard fire signal. This method definitely applies for shutter speeds that do not exceed the sync-speed.

I'm not sure whether there is a corresponding digital signal, though. I do know that there are a few flashes which won't fire, even when you connect their centre pin against ground. These flashes require digital communication with the camera. This could mean that the flash doesn't enable the standard firing method before it has "talked" to the camera, but it could also mean that such a flash "listens" for a digital fire signal.

I don't imagine a "quench" signal is relevant to digital TTL ...

Correct, it isn't.

The quench signal was used for analog TTL. The moment the camera sensed that enough light has fallen on the sensor, it activated the quench pin, thus causing the flash to immediately stop creating output. As inkista wrote, the length of the output determines the power of the output (for IGBT-controlled flashes, i.e., all speedlights).

N.B., I'm keen on trying the XPro-P, but I'll await the release of the Mark II version for Pentax. The Mark II version has more functionality (e.g., Bluetooth) and quicker access to many functions.

[stevebrot]

I'd assume the fire/sync signal, however, is still analog (short from sync to ground), as that's part of the ISO standard for hotshoes.

I'm not sure whether there is a corresponding digital signal, though. I do know that there are a few flashes which won't fire, even when you connect their centre pin against ground. These flashes require digital communication with the camera. This could mean that the flash doesn't enable the standard firing method before it has "talked" to the camera, but it could also mean that such a flash "listens" for a digital fire signal.

Some months ago I quite by accident* discovered strong indication that neither the pre-flash or main P-TTL discharge are fired from the center contact. The clue was that while the center contact (pc fitting too) on my K-3 is "dead" above the X-sync speed, P-TTL dependent HSS works even though. HSS in Pentax-land is, after all, just a special case of P-TTL.


Steve

* I was trying to piggyback a hard-wired discharge from one of my speedlites onto the main flash from my P-TTL flash set up for HSS.

[mcgregni]

My assumption was that the term "quench signal" was referring to camera to flash communication (for film plane TTL), and flash light sensor to flash (internally) for thyristor types.

How digital P-TTL flashes technically turn their output on and off internally is beyond my electronics knowledge, but also surely beyond what an operator and controller of flash exposures needs to know ...? There has to be a calculation of duration, but inkista, you seem to be suggesting that this is carried out by the camera and communicated at the point output ceases..... But P-TTL output is all pre-determined during the pre-flash stage, so it seems more likely to me that a coded data message is sent from the camera containing the "output instruction" ...(is this a time value or something else that is converted to a duration inside the flash?)..

But in any case, it seems to me that exactly how a digital TTL flash technically achieves the right duration has little significance to practical P-TTL flash operation.

The coded message could be something like this ...(English translation) .."Turn on ...wait 1/10,000th sec ....Turn off". But I am thinking this is all carried out by the internal electronics of the flash, and not through hotshoe contacts (apart from the data transmission at the end of the pre-flash stage).