[mcgregni]

Thanks, I think we're starting to unravel this now ... These subtle differences I think have not been communicated clearly yet by Cactus themselves, probably because they have only issued the Quick Start sheets for X-TTL, not complete user Manuals. I have detected hints of these issues in various Cactus forum discussions (eg Antonio saying to use the long press on the menu button to switch between TTL and M modes for the on -camera flash).

At this point in time I believe I have still been seeing the previous behaviour for this action, ie switching TTL Passthrough on and off, so I wonder if there's a bug. However now with more understanding of what should be expected I can test this more. There's no reason for my AF-540FGZII not to work as expected (it presumably is the model that Cactus used themselves?) ....perhaps it's the K7 where some incompatability exists .....?

I also have found the concept of the "fifth group" confusing, mainly because there does not seem to he a display aspect related to it ....I have not yet seen any display information for the on-camera flash, apart from the usual tiny TTL indication at the bottom left to show passthrough is activated. Without a clear display relating to "fifth group" it will be difficult to gain good control over it .....however maybe I have not been working it properly, as I assumed that the concept of TTL passthrough was the same as on the multi-brand firmware. I will test it tonight by combining the menu button and turning the dial .... Who knows, maybe the display will magically come to life and let me set my on-camera flash exactly ....... However it will not be easy to keep good control over things (in the manner that Photodana wishes to use the system) if the"fifth group" display disappears apart from when it is being adjusted.

It is only through this discussion and your prompting that I was led to consider a possible difference in the passthrough concepts ..... I do not think there has been any effective explanation of these differences from Cactus themselves when releasing the X-TTL varient, therefore no general understanding that operating that part of the device had changed.

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Last edited by mcgregni; 04-15-2018 at 03:16 AM.

[Class A]

These subtle differences I think have not been communicated clearly yet by Cactus themselves, probably because they have only issued the Quick Start sheets for X-TTL, not complete user Manuals.

Yes, I agree that while the quick start guide is useful, it is not a full replacement for a proper manual. I've been suggesting to Cactus that a full blown X-TTL manual would be useful, but I guess they have been very busy with completing the X-TTL support and developing the RQ 250.

...perhaps it's the K7 where some incompatability exists .....?

Possibly.

Wouldn't make a lot of sense to me since the K-7 seems to be compatible as far as off-camera flashes are concerned and according to my hypothesis in the X-TTL variant an "on-camera" flash is pretty much treated like an off-camera flash (including flash system translation). So my money would be on the flash model rather than the K-7. However, that's just speculation.

I also have found the concept of the "fifth group" confusing,

I call it that; I'm not sure anyone else does.

mainly because there does not seem to he a display aspect related to it

Have you tried keeping the menu button pressed while turning the dial?
That temporarily brings up the screen for the "fifth group" on the multi-brand firmware.

[Photodana]

YES! I cracked the code (about TTL Key light/fill light). It is embarrassing simple. (This reminds me of Lightning McQueen trying to turn on a dirt track): In order to reduce the fill light, turn up the key light! It's that simple! The TTL metering system will see to, that the final exposure is OK/the fill light is reduced correspondingly :-) Basic editing only: Crop, Auto Contrast, Resize, Save for web.

[mcgregni]

PEN.A.001 "TTL PassThrough" Testing

I got it going .... although there are some bizarre behaviours, which suggests this feature is buggy in some way. I'll just list things as I found it :

• The setting preventing my AF-540FGZII firing was the Sync Mode (Function Menu) - this was set to 'HSS OFF'. When changed to 'Normal HSS' the flash started working
• The flash continues working whilst the flash head was in a bounced / rotated position - when the flash head is returned to its front facing position it stops working again .... and the V6II Sync Mode goes back to 'HSS OFF' . It is impossible to return the sync mode back to 'Normal HSS' without recycling all the equipment off and on. The flash head must remain in a bounced / rotated position in order for the Sync Mode to remain at 'Normal HSS' and for the flash to continue working.
• The controls work in this manner : 1. Long press on the Menu button cycles between TTL and M for the PassThrough flash. The only indication is the tiny TTL bottom left to indicate TTL mode. There is no indication for M mode. 2. Pressing the Menu button and simultaneously turning the dial brings up a single display item for the compensation setting (TTL) or the Flash Power level (M).
• It is easy to imagine that TTL Passthrough is not activated when set to M mode, as there is no indication. It confused me before!
• You have to be fairly quick after pressing the menu button to turn the dial in order to make adjustments, because otherwise it becomes a long press and flicks into the other mode
• Metering is not right for me ..... the 0.0 compensation setting produced exposures about 2.0 stops too low. Keeping the setting at +2.0 produced good exposures.
• The differential between compensation stop settings was good and consistent, and other flash metering aspects seemed consistent and normal, eg the differences between zoomed in and wide angle shots. Changes to aperture and ISO did not affect TTL flash exposures, as expected
• Compensation settings on the Flash controls itself appeared to have little effect
• HSS worked normally, with consistent flash exposures holding well between 1/180th and 1/2000th, with a steady drop in flash exposures beyond that, which is consistent with what I have seen from the slave flash performance with this system

OK, so my feelings so far ..... at least it works and I could use it if needed. There seems to be the same metering problem with Photodana's shot above, as the Fill Flash is underexposed at a 0.0 setting, as he reported above. I will try and test later with a TTL slave working also to see how the flash balancing works out between the two. With two slaves I have not seen the behaviour described by Photodana, I have seen the flash exposure of each slave hold its own against the other, not change in any way .... so for example I have seen plus compensations on one slave have no effect on the output from the other slave (which is what I would want really), and this is also how the Pentax Optical system responds also. I will test this also with the passthrough flash and report back.


Generally I found it awkward to operate the adjustments on the V6II, as I was handholding. I had to place the camera down on a table each time to adjust as it needs both hands, so I would actually prefer to be able to make the adjustments on the flash controls directly, ie in the manner of a 'traditional' TTL PassThrough concept.


Update : I've tested now with a Radio TTL Slave (RF60x) on Group A, with the Pentax AF-540FGZII continuing in the TTL PassThrough role, and I have found the flash exposures to be remaining independent of each other .... I shot a big cardboard box with light bounced from the on camera flash from over my shoulder back onto the top of the box, while the Slave flash bounced light from a wall onto the side of the box, and apart from a bit of light spill from one to the other I was able to exert very precise control over each surface of the box, and there appeared to be no connection between the two flash exposures. A flash compensation setting applied on the camera itself (flash modes screen) had an effect of globally adjusting the exposures from both flashes equally, as expected.


The compensation problem with the passthrough flash continued, always needing about +2.0 for a good exposure, while the slave flash was OK, needing about +1.0 for a tightly zoomed in subject, again that's normal. Zoomed out with a wide view flash exposures were brighter , again normal behaviour.

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Last edited by mcgregni; 04-15-2018 at 07:58 PM.

[Class A]

The flash continues working whilst the flash head was in a bounced / rotated position - when the flash head is returned to its front facing position it stops working again .... and the V6II Sync Mode goes back to 'HSS OFF' .

I just found a bug report on the Cactus Community forum that seems relevant to the difficulty you had to get it working.

It is easy to imagine that TTL Passthrough is not activated when set to M mode, as there is no indication.

I don't quite understand. If you select manual mode, there is no "TTL pass-through". As a matter of fact, using the X-TTL firmware variant, there is never a true "TTL pass-through" only the option to control the on-camera flash in TTL mode.

Metering is not right for me

How would you know which output would be the correct one?
If you remove the V6II and use optical triggering, does the on-camera flash use more power in this case?

Compensation settings on the Flash controls itself appeared to have little effect

I don't know what the intended behaviour is. Your statement sounds a bit inconclusive, though. Was there some effect or not?

There seems to be the same metering problem with Photodana's shot above, as the Fill Flash is underexposed at a 0.0 setting, as he reported above.

Photodana had the opposite problem, didn't he?
He wanted less fill flash, whereas you seem to be wanting more.

Generally I found it awkward to operate the adjustments on the V6II, as I was handholding. I had to place the camera down on a table each time to adjust as it needs both hands, so I would actually prefer to be able to make the adjustments on the flash controls directly, ie in the manner of a 'traditional' TTL PassThrough concept.

You are referring to making changes to the on-camera flash via the V6II, right?
I agree that the two-handed operation approach is not ideal. I guess for those using on-camera flash, it might be nice to re-purpose group D (or so) to reference the on-camera flash. That would allow one-handed operation throughout.

[Class A]

Just found this on the Cactus Facebook page: A demonstration of the various "TTL pass-through" modes for the V6, V6II, and V6II running X-TTL! And here's the killer: The video even uses Pentax gear!!!

You Tube

You Tube

Usage is the same in all three cases but note that Cactus confirm that the V6II running X-TTL does not do a real "TTL pass-through" anymore, just as I gathered from following comments on the Cactus community forum.

@mcgregni
Interestingly, the flash on the V6II + X-TTL seems to produce a perfectly fine exposure. So I'm unsure what you mean by a two stop underexposure. Perhaps there is an interaction with the off-camera flash but judging by the video, the very same should happen if the on-camera flash is mounted on the camera directly.

[mcgregni]

That video gives some clarification, yes ...." Its TTL PassThrough Jim, but not as we know it " . Actually, its not 'true' Passthrough, and I see the reason is that it allows other camera system types to be used on the V6II also, whereas the previous Passthrough was only for flashes from the same system as the camera. Its a pity there is still a reference to "TTL PassThrough" in the X-TTL Quick Start Guide, and also there is a menu item to activate it within the Function menu... I think this will continue to confuse because of that. In fact the activation in the menu is simply another way to switch on the TTL mode for the on-camera flash. Without that switched on then it defaults to Manual.


I re-tested again, this time with the flash directly on the camera (no V6II), the same image with 90deg bounce from a wall, and I got good exposure immediately ....(by that I mean midtones around 30-50% on the histogram, highlights at about 75%. But once I added in the V6II, same image, same bounce, same settings, I got it about 2 stops underexposed (midtones around 15-30%, highlights at around 45%). Setting a +1.5 stop compensation brought this exposure near to that taken without the V6II.

If you remove the V6II and use optical triggering, does the on-camera flash use more power in this case?

... Yes, about 1.5 to 2 stops more

I don't know what the intended behaviour is. Your statement sounds a bit inconclusive, though. Was there some effect or not?

I checked again, and this time the compensations made on the flash itself did in fact have a cumulative effect on top of the V6II compensation setting and the adjustments seemed to have the expected full effect for each stop I input, both up and down. There is only one other setting I changed from last night, and that was the flash profile, which was previously set to Auto Pentax, and I changed it tonight to AF-540FGZII (I had hoped I might have found the cause of the exposure problems also, but alas not), so I can only assume that this profile setting changed the behaviour of the flash compensation setting.

..... it might be nice to re-purpose group D (or so) to reference the on-camera flash. That would allow one-handed operation throughout.

That would be excellent yes, and being able to operate the on camera flash in the exact same way as the slaves would be ideal. I would think that it is extremely unlikely that anyone would be wanting to operate 4 slave groups plus an on camera flash, so allocating one Group when there's an on camera flash should not be a sacrifice. Most uses for on camera flash with the V6II are going to be scenarios like Photodana's, a simple set up with one slave and a need for fill-in.

Interestingly, the flash on the V6II + X-TTL seems to produce a perfectly fine exposure. So I'm unsure what you mean by a two stop underexposure. Perhaps there is an interaction with the off-camera flash but judging by the video, the very same should happen if the on-camera flash is mounted on the camera directly.

Actually, I observed on the video that the exposures taken with the multi-brand firmware were significantly brighter than that taken with the X-TTL firmware, which looked underexposed to me .... I didn't see that he changed anything in the key settings, and the scene he pointed at was the same.


I will add the key issues here to a report and post it at Cactus Community Forum, hopefully they will be able to incorporate a fix in a future firmware update. I'm not personally too bothered as I am unlikely to be using an on camera flash now with the V6II, since I have 2 RF60/x flashes, so I think I will tend to use a reflector for fill now. I do think the general discussions here have been helpful and added to the general understandings of the Cactus system and the subtle developments recently.

[Cactus]

That video gives some clarification, yes ...." Its TTL PassThrough Jim, but not as we know it " . Actually, its not 'true' Passthrough, and I see the reason is that it allows other camera system types to be used on the V6II also, whereas the previous Passthrough was only for flashes from the same system as the camera. Its a pity there is still a reference to "TTL PassThrough" in the X-TTL Quick Start Guide, and also there is a menu item to activate it within the Function menu... I think this will continue to confuse because of that. In fact the activation in the menu is simply another way to switch on the TTL mode for the on-camera flash. Without that switched on then it defaults to Manual.

We are glad to hear the video helped.

And good point on the old wording - TTL Pass Through - we shall update it on subsequent version of the X-TTL Quick Start Guide. Thanks for pointing this out.

.... But once I added in the V6II, same image, same bounce, same settings, I got it about 2 stops underexposed (midtones around 15-30%, highlights at around 45%). Setting a +1.5 stop compensation brought this exposure near to that taken without the V6II.

This used to be bug on Multi-brand HSS, a tilted / rotated flash head, would not function properly. We shall fix this on the next firmware release.

I will add the key issues here to a report and post it at Cactus Community Forum, hopefully they will be able to incorporate a fix in a future firmware update...

Yes indeed we will include these fixes on the next firmware version and we very much appreciate your efforts in helping us out.

Thank you!

[mcgregni]

Great , good to hear from you Cactus, and thanks for your response, much appreciated.

[Cactus]

Great , good to hear from you Cactus, and thanks for your response, much appreciated.

We appreciate your patience while we get the new firmware ready.

Thank you!