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06-01-2018, 05:26 PM   #1
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Why do I need Cactus?

I have read a lot of posts about the Cactus wireless system. They quickly become very technical, and I'm not sure why the system is to be preferred over using several P-TTL flashes (I have an AF360FGZ II and a Metz 52 AF-1 and my son has a Sigma PTTL ring flash for macro work).

There's a sale on Cactus gear at Digital Camera Warehouse in Australia at the moment. I am looking at the V6 II and the RF60x. Can somebody with experience list what I would be able to do with these that I can't do with P-TTL?

I am also a bit confused about how TTL (or is it XTTL) combines with this system.

06-01-2018, 05:41 PM   #2
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I think ttl only works with v5. The v6 allow hss. They work with mutiple brands mixed together. You can have 4 groups and 1 on camera. You can control each groups power from the camera from 1/128 to full power.
06-01-2018, 06:05 PM   #3
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The Cactus V6II supports TTL.

The page below mentions the specification.

https://www.cactus-image.com/special/X-TTL/

Last edited by C_Jones; 06-01-2018 at 06:12 PM.
06-01-2018, 06:09 PM   #4
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Ok i thought it was only pttl but could be used to trigger v5 with ttl.

06-01-2018, 06:17 PM   #5
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I have the V5 units and they don't communicate the P-TTL, so I just use them in Manual mode. They have a grouping feature, but do not have a digital display. I really like them, they work very well, although they do not facilitate remote flash power control.
06-01-2018, 06:21 PM   #6
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Digital display? I have v5. It displays group power etc. What display would you want?

Edit. I have v6 but Not v6ii.
V6ii- 1 version does not equal v5.

Last edited by swanlefitte; 06-01-2018 at 06:26 PM.
06-01-2018, 06:26 PM   #7
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This thread explains some other factors that may be pertinent.

https://www.pentaxforums.com/forums/125-flashes-lighting-studio/355535-cactu...available.html

---------- Post added 06-01-18 at 09:34 PM ----------

The V5 uses dials for its grouping feature. It is very easy to use.
06-01-2018, 09:59 PM   #8
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The main advantage for me is the V6ii allows the user to get above the max flash sync speed on a Pentax, therefore potentially allowing faster speed for say macro ( bee's in flight ) or portraits against the sun.


Instead of being restricted to1/200th ( K1 ) I can shoot up to 1/8000 should I wish to, without resorting to ND filters and you could sync several RX60 units either on separate channels or all on one and control the power from the camera.

06-02-2018, 01:36 AM   #9
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In this context then TTL equals P-TTL .....this is just the Pentax version of digital automatic flash exposure (Program Through The Lens).

Pentax and other dedicated system flashes use “Optical P-TTL”, and the Cactus V6II system offers “Radio P-TTL” and “Radio Manual”. For Radio P-TTL you need to use the firmware versions known as X-TTL ....there is an X-TTL firmware for the V6II and another firmware for the RF60.

Why should you choose it? When you think that Optical P-TTL is limiting you technically, for example with a restricted working range, or the optical communications are unreliable in bright sun (possibly), or you find flash exposure control of the slaves difficult (given that you need to set individual ratio and compensation levels directly on each flash). With the optical system you can only control global flash exposure from the camera.

So if you want to enjoy remote control over the flash outputs in both manual and P-TTL modes, plus remote control over flash head zoom, and adding in 2nd curtain sync in manual mode as well, then the V6II offers that. Also with the RF60x there is AF Assist from the slave flashes, a red beam type, which combines with a beam from the on camera trigger.
07-29-2018, 04:42 PM   #10
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Question, would the orginal RF60 work in HSS as well using a V6II? I have an older one and am curious if I would need to get a V6II and a RF60X or not. Also, would i be able to use an RF60X on the camera using HSS and PTTL? That would be great.
07-29-2018, 06:00 PM   #11
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QuoteOriginally posted by Navmaxlp Quote
Question, would the orginal RF60 work in HSS as well using a V6II? I have an older one and am curious if I would need to get a V6II and a RF60X or not. Also, would i be able to use an RF60X on the camera using HSS and PTTL? That would be great.
I believe the RF60 should allow HSS with V6 II. You may need to update the firmware to version 200 or higher. I believe this also makes it incompatible with the V6 I, although supposedly there is a firmware coming out soon that makes the V6 I more compatible with the V6 II. The main additions to the RF60X is improved charge time, an AF assist light and better prevention of overheating.

---------- Post added 07-29-18 at 09:39 PM ----------

QuoteOriginally posted by Paul the Sunman Quote
I have read a lot of posts about the Cactus wireless system. They quickly become very technical, and I'm not sure why the system is to be preferred over using several P-TTL flashes (I have an AF360FGZ II and a Metz 52 AF-1 and my son has a Sigma PTTL ring flash for macro work).

There's a sale on Cactus gear at Digital Camera Warehouse in Australia at the moment. I am looking at the V6 II and the RF60x. Can somebody with experience list what I would be able to do with these that I can't do with P-TTL?

I am also a bit confused about how TTL (or is it XTTL) combines with this system.
The main draw of the V6 II is the RF wireless transmission of the P-TTL signal. In short, the P-TTL signal is transmitted through the hotshoe and basically tells the flash unit some information about the exposure, the flash does a pre-fire and the camera/flash will evaluate the result to determine the actual flash power to properly light the scene; it is essentially auto exposure for flashes. The V6 II is able to take that data from the hotshoe and transmit it wireless to a remote flash unit. There are other wireless RF triggers, but they do not transmit P-TTL signal, so the flashes need to have their power level set manually. The other wireless P-TTL system native to Pentax flashes relies on optical triggering from the pop-up flash or an on-body flash acting as a controller/master. In some lighting situations, the contribution of the on-body flash is undesirable, but with this setup relying on optical triggering, it is difficult to prevent. In theory, you could put an IR-pass filter over the flash, but that can be unweildly at times.


In short, the V6 II allows you to have a flash remotely placed and have its power set automatically.


The RF60X with their Pentax firmware is basically a Pentax P-TTL flash with a Cactus V6 II built in, with the opportunity to also change it to some other brand should you choose to switch systems or sell the RF60X. You could also just buy more V6 II for your current flashes. It is also a HSS so you can use it above the sync speed.


You can also remotely adjust the power level of the remote flashes. Instead of having to go to each unit to adjust the +/- EV or power ratios, you can do that from the on-camera transmitter.


Finally, the V6 II can work with multiple systems, hence the X-TTL nomenclature. In theory, you can borrow someone's Canon E-TTL flash or Nikon iTTL flash and have it work like a P-TTL flash. There is a note about incompatability regarding the P-TTL system, but I am not sure if that means Pentax bodies can't use other brand TTL flashes, or other brand bodies cannot use P-TTL flashes.
08-01-2018, 08:21 AM   #12
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QuoteOriginally posted by Navmaxlp Quote
Question, would the orginal RF60 work in HSS as well using a V6II?
Yes, you just need a recent firmware version.

QuoteOriginally posted by Navmaxlp Quote
Also, would i be able to use an RF60X on the camera using HSS and PTTL?
No, if you mean "directly mounting the RF60X to the camera's hot-shoe".

You always need to involve a V6II if you want to use HSS or P-TTL, the RF60X on its own does not support the required digital communication with the camera.

QuoteOriginally posted by sprint113 Quote
In theory, you can borrow someone's Canon E-TTL flash or Nikon iTTL flash and have it work like a P-TTL flash.
That's not quite true. Cross-brand HSS is supported, but P-TTL only works with P-TTL compatible flashes (or the RF60/RF60X/RQ250). Cactus state that timing differences between P-TTL and other flash systems prevented them from fully realising the X-TTL approach for Pentax.
08-01-2018, 08:37 AM   #13
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QuoteOriginally posted by Class A Quote

That's not quite true. Cross-brand HSS is supported, but P-TTL only works with P-TTL compatible flashes (or the RF60/RF60X/RQ250). Cactus state that timing differences between P-TTL and other flash systems prevented them from fully realising the X-TTL approach for Pentax.
Ah, I remembered that Pentax had some incompatibility, and couldn't remember if it was Pentax flashes not working with other bodies or Pentax bodies not working with other flashes. Well, maybe they'll be able to find an "impossible" solution down the road.
08-07-2018, 08:17 AM   #14
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QuoteOriginally posted by Paul the Sunman Quote
I have read a lot of posts about the Cactus wireless system. They quickly become very technical, and I'm not sure why the system is to be preferred over using several P-TTL flashes (I have an AF360FGZ II and a Metz 52 AF-1 and my son has a Sigma PTTL ring flash for macro work).

There's a sale on Cactus gear at Digital Camera Warehouse in Australia at the moment. I am looking at the V6 II and the RF60x. Can somebody with experience list what I would be able to do with these that I can't do with P-TTL?

I am also a bit confused about how TTL (or is it XTTL) combines with this system.
My experience may be of help. I've had an RF60x and two V6ii for a few months; I've played with it in manual mode and using a Metz on one of the V6ii - the results were OK, but lot of effort involved. When the xTTL firmware was released, I tried it straight away... and found it unreliable.

Last week I received the DFA*50 - WOW - great lens, so I thought I would try the flash with it. Updated the firmware on both the V6ii's and RF60x, what a difference!! Using in Av mode, it worked as a fill-in to natural light with no problems in HSS domain, just wound down the power -0.7 to balance the exposure. Indoors, good result using M on the camera.

As mentioned above, the P-TTL only works with Pentax and Cactus RF60x flashes. I haven't tried the Metz remotely, but as it does P-TTL on the camera I expect it will - just no HSS as it isn't capable...
08-07-2018, 09:28 AM   #15
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Just for clarity, the XTTL firmwares provide TTL/HSS with P-TTL dedicated system flash types (HSS as you said only if the flash offers that), plus the RF60 and RF60x flashes.

Last edited by mcgregni; 08-07-2018 at 10:05 AM.
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