[howieb101]

Well here are

We just disagree whether Cactus actually advised someone against their better knowledge.

Well, here are just two posts where Antonio recommends an additional V6 be attached to the Godox light (a AD200 in the first example and a V860 in the 2nd post).
Compatibility with Godox AD200 ? Cactus Community (Post #2 by Antonio)
V6ii on Pentax and godox flash ? Cactus Community (Post #2 by Antonio)

I have the AD200 and I definitely do not require the additional V6 II to be attached to the AD200 to get HSS (the setup is a Godox Xpro-C on top of a Cactus V6 II).

I know they do not recommend trigger stacking but it works well with lots of Godox lights. If you were using a three light setup you would end of buying four Cactus V6 II's if you followed Antonio's recommendations when you only need to buy one.

I know this applies to using a number of Godox lights and may not apply to other trigger systems and flashes. Still, it is worth other Pentaxians knowing if it will save them some money.

[mcgregni]

Just going back to the point about HSS being only compatible with A series lenses or autofocus ones ...... testing I've done tonight seems to suggest that this incompatibility exists not only for HSS operation with the V6II, but for Manual Mode working also.


This is not something I would have expected. Obviously both TTL and HSS would logically require the camera/trigger systems to have the aperture information, so it is understandable why those modes would not work with a manual aperture lens.


I was testing with my old Tamron Adaptall 135mm, plus some basic extension tubes. I normally work this lens with the tubes with its aperture set to Manual (where it stops down in response to the aperture ring settings, and remains stopped down). This is the only way to set a desired aperture, as the tubes have no contacts to allow the camera to set the aperture. Previously I have used my V6 plus RF60 flash with this set-up, and used manual flash control with no problems.


However, tonight , with the V6II and PEN.A.001 firmware, with the flash mode set to Manual, I was unable to gain any good control over the flash exposure. The RF60x display showed the changes to zoom and flash power I was making on the V6II, but the actual light output was not consistent. I would get some very overexposed shots, then some dark ones with only a 1 stop change in power. Also making 1 stop adjustments to ISO and aperture had unpredictable results. The only conclusion I could draw was that the Cactus system was not outputting the power setting as dialled in, and it was varying between shots seemingly randomly.


I also tried with an RF60x on the camera as 'Master', and RF60 as slave (both running one of the 'X-TTL' firmware's), and again there was no consistent Manual power control ....... hmmm, seems strange, but perhaps just a consequence of the way the firmware works. Its a pity, as it means that for my close up/macro work I'll have swap the firmware on my Cactus flashes back to the Multi-Brand one and use the V6 again .....


Changing the lens back to the D FA28-105 solved all the problems and I regained perfect manual control again.


I have seen the posts on Cactus Community Forum where Antonio explains to ClassA that eventually there will be a merging of the firmwares, allowing mixing of the different types. It appears to be that for those of us wishing to use both autofocus lenses with TTL / HSS, and old manual aperture lenses with Manual flash, then this could not come soon enough!

[Class A]

Well, here are just two posts where Antonio recommends an additional V6 be attached to the Godox light (a AD200 in the first example and a V860 in the 2nd post).

Well, in the first post you quote Antonio mentioned the option of trigger stacking, so he gave the person enquiring a clear pointer to a cheaper solution. I don't think you can ask for more than that.

In the second case, I agree with you that Antonio suggests that there is no other solution than buying two V6II. In Antonio's defence,

1. the person enquiring did not state whether they already have a Godox trigger or not. They just mentioned a V860 flash so if that is all the equipment then another device is needed when one makes the assumption that the flash will be used as an off-camera flash.
2. if you want to remote control the power levels and zoom of a V860 via the on-camera V6II, which is not an unreasonable assumption to make, given the enquiry, then a second V6II is indeed needed.
3. the person specifically asked whether the V860 will work on a V6II, so the enquiry wasn't really about the cheapest option for using the V860 with a V6II, but whether the two devices are directly compatible with each other. It turns out, that they really wanted to know whether the V860 works as an on-camera flash with a V6II sandwiched between the V860. As soon as that was established, Antonio confirmed that a single V6II is sufficient.
4. I don't think Antonio can responsibly point out trigger stacking as an alternative solution without a number of disclaimers, given that this approach may not continue to work indefinitely. Future Godox triggers and/or future Cactus firmware versions may not support this approach anymore. In that sense, it is fairer to assume that two V6II will be needed (for off-camera flash).

I agree that ideally Antonio should have mentioned the unsupported trigger stacking with a disclaimer as he did in the first post you pointed to. Then the person enquiring could have made a decision as to whether to buy a Godox trigger (if they don't have one already) or an additional V6II. Having no guarantee that the approach will be supported by future firmware versions may have been acceptable to them (as you can for instance just stick to working firmwares instead of upgrading).

However, note that even the second conversation ended with a cost-minimal solution.

I know they do not recommend trigger stacking but it works well with lots of Godox lights.

Yes, but not with all of them and some need to be configured correctly. The main problem, though, are the Godox triggers; some of which don't seem to be working at all, others only with certain V6II firmware versions, and all, I believe, require some overall configuration (V6II included).

It is great that it works in some cases, but it may be a bit much to expect from Cactus to track success stories and advise people accordingly.

Still, it is worth other Pentaxians knowing if it will save them some money.

Absolutely!

I'm not Cactus' lawyer so I don't want to defend them more than necessary, but from what you have shared here, I wouldn't conclude that they are deliberately withholding information from people in order to increase their sales.

[Class A]

However, tonight , with the V6II and PEN.A.001 firmware, with the flash mode set to Manual, I was unable to gain any good control over the flash exposure. The RF60x display showed the changes to zoom and flash power I was making on the V6II, but the actual light output was not consistent.

Did you set the RF60X's group to "M" (manual) on the V6II?
Did you use shutter speeds that did not exceed the sync-speed?

If so, your results are not good at all. AFAIC, the V6II should not care about the lens, as long as the above two conditions are met.

I also tried with an RF60x on the camera as 'Master', and RF60 as slave (both running one of the 'X-TTL' firmware's), and again there was no consistent Manual power control ....... hmmm, seems strange, but perhaps just a consequence of the way the firmware works.

That doesn't make sense to me at all, unless it happens with any lens for some reason.

The RF60X lacks any means of digital communication with the camera, so it doesn't know whether the attached lens has an "A" mode, is fully manual, or whatever. The RF60X should work independently of any P-TTL matters (like HSS or lens type).

This experience suggests to me that your conclusions about the V6II not working with a fully manual lens may not be correct, or that there are multiple bugs (in the V6II and RF60(X)) involved.

Changing the lens back to the D FA28-105 solved all the problems and I regained perfect manual control again.

Did you try the RF60X on-camera again?

As I said, I believe it to be technically impossible for the type of lens to have any influence on the reliability of the communication between an on-camera RF60X and an off-camera R60.

I have seen the posts on Cactus Community Forum where Antonio explains to ClassA that eventually there will be a merging of the firmwares, allowing mixing of the different types. It appears to be that for those of us wishing to use both autofocus lenses with TTL / HSS, and old manual aperture lenses with Manual flash, then this could not come soon enough!

I don't understand how you arrive at this conclusion.

Did you not just report an issue with the "A"-type firmware? If that is confirmed then the announced roll-out of the "A"-type approach to all firmware variants could mean that the latter get broken as well.

I hope your issues can be explained in a different way. Otherwise, I'd encourage you to report the problem to Cactus before it spreads to all other firmware variants.

[cameradork]

Hey guys,

Finally my 45-85 arrived today and hss worked immediately, upto 1/4000 (with very slight darkening of the top of the frame) with a Vii on the hot shoe, and one into the sync port on the AD600.


Looking forward to trying the 35A when it shows up.

I have yet to try any other trigger setups, but hoping to try a Profoto b1, a Godox canon trigger and the ft16 setup this weekend.

Thanks for all the help!

-Tony.

[mcgregni]

Great to hear its up and running now ... I'm not familiar with the 645 line of lenses, but I presume the 45-85 is an FA type, or at least it obviously has aperture contacts to the camera. The A series 35mm should also work OK.

---------- Post added 26-04-18 at 18:43 ----------

Did you set the RF60X's group to "M" (manual) on the V6II?Did you use shutter speeds that did not exceed the sync-speed?

Yes indeed, yes to both of these (but if course it was not possible to go beyond the max sync speed). The power settings were observed changing on the RF60x display in response to inputs on the V6II, but as I reported the actual flash outputs were inconsistent and not really controllable.


I have re-tested this, and can add some more detail now ..... specifically I found this problem to only occur with the RF60x unit, when working as slave with V6II as Tx. The older RF60 showed no issues at all under the same conditions (ie X-TTL firmwares, M flash mode on V6II, old lens with tubes and no aperture contacts). The RF60x is running A.03, and the RF60 A.02. I will update these to the latest soon, but there's nothing in the firmware notes to suggest this would help .....


I have not yet re-tested with the RF60x as Master on the camera with a DA lens ..... I see your points ClassA about how the lens should not have any effect with this, but I'll check. As you say, the problem should exist regardless of the lens.


I also see your point about the rollout of A type firmwares ..... obviously if this is a universal bug then it may spread to everything. However I am a bit reluctant to complain to Cactus really .... it seems fairly unreasonable to demand their digital TTL flash trigger system should provide support for lenses more than 35 years old (pre A series). Of course Manual mode is exactly what is needed for these old lenses (as indeed it is within the Pentax flash system also, unless you have an Auto-Thyristor flash), and we Pentaxians are big on the whole 'backward compatibility' thing in lens terms ..... but is it really fair to expect Cactus to also embrace such an ambition?

[Class A]

I have re-tested this, and can add some more detail now ..... specifically I found this problem to only occur with the RF60x unit, when working as slave with V6II as Tx. The older RF60 showed no issues at all under the same conditions (ie X-TTL firmwares, M flash mode on V6II, old lens with tubes and no aperture contacts).

Strange.

The RF60x is running A.03, and the RF60 A.02. I will update these to the latest soon, but there's nothing in the firmware notes to suggest this would help .....

If a firmware update doesn't help, could you please report it to Cactus?

First, I think such inconsistent behaviour should not exist. The RF60 is definite proof that it need not exist. Also, if there is something wrong, it could manifest itself in other circumstances and hence I think for that reason alone Cactus should appreciate your bug report regardless of whether or not they think the RF60X should support manual lenses as well as the RF60 does.

However I am a bit reluctant to complain to Cactus really .... it seems fairly unreasonable to demand their digital TTL flash trigger system should provide support for lenses more than 35 years old (pre A series). Of course Manual mode is exactly what is needed for these old lenses (as indeed it is within the Pentax flash system also, unless you have an Auto-Thyristor flash), and we Pentaxians are big on the whole 'backward compatibility' thing in lens terms ..... but is it really fair to expect Cactus to also embrace such an ambition?

I think it is more than fair to expect that there isn't any unnecessary inconsistent behaviour. I also don't regard using a manual lens as exotic, in particular not with a trigger system that has been quite focused on manual control for a long time and still has strong support for it.

Cactus themselves are big on compatibility and backward compatibility. As a matter of fact you could argue that the Cactus transceivers are designed to make old/existing gear work with new cameras (see the V6 that made old analogue TTL flashes useful again, or the V6II that supports reusing one's system flashes instead of having to buy new lighting solutions). So my view is that they shouldn't regard your bug report as being out of line. See also above, as to why removing the bug may not only help with using manual lenses but potentially in other circumstances as well.

N.B., I think a bug report shouldn't be mistaken with a "complaint". An irate complaint letter with a rich set of expletives but sparse on technical details probably won't evoke happy feelings, but a well-written bug report that ideally allows a problem to be replicated should be welcome by any company.

[mcgregni]

I'll try and avoid too many expletives ..... OK, I'll make a report to Cactus. It would be reassuring to know that compatibility with manual aperture lenses and basic tubes can be secured going forwards, even if there is a merging of firmware types with the V6II and RF60x. I note also that the RF60 is a discontinued model, so new buyers will not have the current advantage I have of being able to use it if needed. Of course I also would like to be able to use two flashes if needed in combination with an old lens / and tubes.


Here's what all this is all in aid of ..... here I put it into action with the V6 and RF60 last year ......











The subject is the tiny purple flower in front of the softbox .......










The current problem means that to repeat this type of shoot I'd have to change the firmware on the flashes back to the multi-brand version and use the V6 as trigger again. Another plus if they can carry out a merging would be to enable the V6 to be used as a Receiver (up to max sync speed) with a V6II as transmitter .... at present it would be necessary to change the firmware on the V6II to the multibrand in order to allow this. It seems though that Cactus are committed to making things more convenient as they progress, and that's a strong aspect of their product offer.

[cameradork]

Quick question. How much power on average do you all think you are losing on hss? I realize this isn’t a Pentax specific question but my guess is I’m losing about 2 stops.

[mcgregni]

Guide Number tables for the AF-540FGZII indicate an approx. 1 stop power loss between 1/180th and 1/250th. That's the immediate price to pay for engaging HS .... GN 54 down to GN 24.


From then onwards there's a further drop in GN for each step up in shutter 'speed' ... (eg 1/500th GN 18.8 .... 1/1000 GN 11.7 .... 1/2000 GN 9.5 .... sort of a decreasing scale). So at 1/1000 you're nearly 3 stops down. This all is approximate of course, and assumes stops equals GN mathematically which I know is not really exact, but this is where it gets beyond my maths skills!


Of course the key difference to note is that below the max sync speed the exposure time value does not affect the GN ....once past the max sync speed then the exposure times have a dramatic effect on GN.

[Class A]

I'll try and avoid too many expletives

OK, I hope you #%$&! manage it.

OK, I'll make a report to Cactus.

Great.

[Class A]

Guide Number tables for the AF-540FGZII indicate an approx. 1 stop power loss between 1/180th and 1/250th. That's the immediate price to pay for engaging HS .... GN 54 down to GN 24.

If the drop is from GN54 to GN24 then that constitutes a 2.34 stop decrease.
Accounting for the difference in shutter speeds, it is a 1.87 stop difference due to switching to HSS.

As you correctly pointed out the main point is that HSS flash will be affected by shutter speed once the shutter speed exceeds the sync-speed. BTW, that's not a limitation of HSS flash, but a natural consequence of focal plane shutters.

[mcgregni]

Thanks for the correction ..... I'm afraid that the maths of flash is not one of my strong points.

[Class A]

Guide number are expressed in a funny "currency", as they are defined by the product of f-ratio * distance. They therefore inherit the stop-basis from f-ratios which is the square root of two rather than just two.

F-ratios use a base of square root two because they are defined as focal-length / aperture-diameter, and each time the area of the aperture (which is the relevant magnitude for exposure) doubles, the diameter of the aperture only increases by the square root of two.

[mcgregni]

Ah, thanks, that's cleared that all up perfectly then!