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10-23-2009, 07:36 PM   #61
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QuoteOriginally posted by GerryL Quote
I do hope that you buy one and debunk the reliability issues so that there would be another source.
I received my Cactus V4 trigger set today and they are great. Even with the transmitter very close to the receivers, they fire reliably. Didn't play extensively with them yet, but 5m distance were not a problem at all.

Syncing at 1/180 is not a problem at all, no black bars whatsoever.

I noticed, though, that putting two receivers very close to each other sometimes causes one of them to not fire. Leaving a space of ~4cm, however, makes all of them fire every time.


Last edited by Class A; 11-26-2009 at 03:49 AM.
11-24-2009, 05:27 PM   #62
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Here's how the Cactus V4 boxes look like.

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Each trigger / receiver pair comes with a manual, a booklet showing strobist examples (images and the corresponding flash setups), and three connector cables.

I just completed my first flash DIY project. I successfully modified my Centon FG105D flash so that it now can be triggered with my Cactus V4 radio triggers.

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Finally, here's my first fun image using two flashes and a bit of ambient light to create a "motion" effect. I know the image sucks in a number of ways but it was fun to do as a quick test whether triggering two flashes would work reliably. It did!

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Last edited by Class A; 11-26-2009 at 03:42 AM.
11-30-2009, 07:55 PM   #63
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i'd just like to note that, these being radio units, distance does matter, self interference and distorsion of the wave will happen at too low a distance. (i work with and support radio equipments which are a bit more expensive than these triggers -- in the 5 figures range -- and it is still true for them). also, keep in mind how much sense it actually makes for their intended use to trigger the receivers with the transmitter a few centimetres away....

on another note: from my experience so far, i would take cactus, who had some buggy triggers released in the beginning, which recalled them, and which respond to customer questions and requests as they do (and to youtube reviewers), rather than some other brand who had no outstanding issues, but is high in an ivory tower. maybe it's just me, but nobody is perfect, i'd rather know you can handle not being perfect properly, when it will happen. my regards to the cactus pr/tech support people.

i recently got the phottix pt-04's. they work fine as stated here too, save for one strange bug: on the 540fgz, under certain conditions, they don't work at all. after some more thorough testing together with my friend (and forum member) levy, we concluded it is the temperature which does it, and more precisely the battery temperature in the receiver. it would be interesting if you guys can test with the cactuses (or is that cacti?) you have (i am not talking extreme here, for quick tests i used the freezer for about one cigarette time ). note that this only happened with the 540, another pentax-compatible flash we had (bottom of the line metz) worked without issues.

i think this might be due to the triggering circuit which does not handle the (alleged) low pentax triggering voltage when the temperature (voltage put out by the batteries) drops bellow a certain level. more on this when i can do further testing.

other than this issue, i am quite happy with how they work, 100% trigger, and no other outstanding issues overall. the hotshoe on them is mounted in a very unfortunate position imho, but i'm not going to be using the hotshoe most of the time anyway.

i will be getting a version -- which apparently isn't really out yet -- tomorrow, and see how that goes, i will do a full writeup somewhere in the forum here as soon as i find the time, on both versions.

oh, there was a question about using them as remote camera release: it should work fine, there should be no voltage on the contacts, just closing the circuit, same for flash as for the electrical cable release, some people have already tried this, all you need is an adapter to plug it into your cable release (of course, if in doubt, measure the contacts before, or, better, don't try )
12-01-2009, 01:34 AM   #64
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QuoteOriginally posted by nanok Quote
on another note: from my experience so far, i would take cactus, who had some buggy triggers released in the beginning, which recalled them, and which respond to customer questions and requests as they do (and to youtube reviewers), rather than some other brand who had no outstanding issues, but is high in an ivory tower.
I agree, their customer service has been outstanding. They promptly answered all my questions before I made a decision to buy the product and were very helpful afterwards as well.

QuoteOriginally posted by nanok Quote
i think this might be due to the triggering circuit which does not handle the (alleged) low pentax triggering voltage when the temperature (voltage put out by the batteries) drops bellow a certain level.
The low trigger voltage of the modern Pentax flashes is not alleged. You can measure it. I believe it is not much more than 3V. In cold temperature even the trigger voltage may drop and if there is a receiver effect added, it may just be enough to cause a problem. I'm sure you know of the modification that was necessary to some triggers to make them sync faster than 1/30 with Pentax flashes due to the low trigger voltage.
QuoteOriginally posted by nanok Quote
i will be getting a version -- which apparently isn't really out yet -- tomorrow, and see how that goes, i will do a full writeup somewhere in the forum here as soon as i find the time, on both versions.
Looking forward to that.

12-01-2009, 06:11 AM   #65
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I have some Cactus v4 -- definitely a significant step above the v2 that was out there. Seem much more reliable and the fact that you can use AAA batteries in them is a definite plus. Overall just seem to be a much better put together product (and still relatively cheap).
12-01-2009, 04:57 PM   #66
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QuoteOriginally posted by Class A Quote
I agree, their customer service has been outstanding. They promptly answered all my questions before I made a decision to buy the product and were very helpful afterwards as well.


The low trigger voltage of the modern Pentax flashes is not alleged. You can measure it. I believe it is not much more than 3V.
around 3v is out i heard as well. i don't have the means to measure that though (i would need an osciloscope, i wouldn't even bother using a multimeter, or am i missing something?)

QuoteQuote:
In cold temperature even the trigger voltage may drop and if there is a receiver effect added, it may just be enough to cause a problem. I'm sure you know of the modification that was necessary to some triggers to make them sync faster than 1/30 with Pentax flashes due to the low trigger voltage.
i am flattered by your confidence , but i don't think i do know. very interested

QuoteQuote:
Looking forward to that.
they are called the "aster pt-v4". they do not work out of the box with the 540fgz. they do kind of work after a bit of a hack (i am wondering if it has anything to do with what you mentioned above). i am not sure what this hack might do to the device, the battery life, and so on, but at first glance it seems to work reliably. i will try to understand the circuitry better, and figure out how bad this hack might be (don't hold your breath though, i'm a bit behind with "modern" electronics, and i see an IC there, which pretty much means..ahem.. i'm out )

apart from that, compared to the previous version (the l-bracket ones, already widespread), they are much nicer built and designed: more compact, smaller, look much sturdier, and, finally, they don't add that huge height to the flash if you want to use the hotshoe on them (they are now "flat"), they use a cr2 (3V) lithium battery in the receiver, the already usual 12v "23a" car remote battery in the transmitter. the transmitter is nice and small (i love that compared to the monstruous pw's, i don't think i'd ever get used to having that lump of plastic on my hotshoe). the receivers are probably about half the size of the previous ones (ymmv, but given that, i think i can live with the cr2 instead of aaa). the size of these new ones means i am no longer scratching my head about what side of the flash i could "stick" the receiver to, should i want to use velcro or whatever, with a pc chord and not hotshoe, because i can stick it pretty much anywhere now. there are new features: a four way switch to select the channel (4 channels still), instead of the binary two switch design (i kind of liked the geekiness of the binary switch ), there is a switch to turn the transmitter off too, this time, and an option to trigger all channels. i am able to trigger the old (l bracket) phottix receivers with the new transmitter, i am not able to trigger the new receivers with the old transmitter (more testing might be in order on that). the build quality and design upgrade show inside too, the rough and "built on a sunday" look of the old pcb is gone (i admit i kind of liked that on the old ones, too..), replaced by a reasonably separated battery compartment, an asymetrical plug for the hotshoe to connect to the pcb, an actual on-pcb mother socket for the pc sync socket, redesigned pcb, with traces which look machine made rather than hand drawn (aaaah, should i mention i was kind of fond of the old ones?.. ). because of the compact design and good plastic used, they look and feel much sturdier than what i have seen so far (i'm not saying they are, just look and feel). oh, there's an optical slave function now on the receiver, i'm not aware if it works or not, i'm not sure i actually give a damn (i have yet to figure out why i would want that, sorry)

edit: forgot one obvious note: the most evident disadvantage of these new ones is that adding an antenna will be more trouble, given the "nicer" pcb design, and because of the shape of the body, it will not be trivial to integrate it somehow with the body (we're talking a square of about 5cm across, and a height of less than 3cm, with hotshoe included, at first glance; so no 14cm antenna to be hidden inside )

there's also a metal tripod mount on the bottom now (opposite the hotshoe), unfortunately, while the idea is very welcome, i am not excited about the way it was implemented (in a hurry). i'd have preferred a brute force, "what the hell, let's put two bolts, and make them big ones" aproach.

hmm, this was not supposed to be a review, just a quick before-i-finally-go-to-bed report (and seeing as i am well over 24h of uptime, take it all with a grain of salt, btw)

Last edited by nanok; 12-01-2009 at 05:06 PM.
12-01-2009, 06:38 PM   #67
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QuoteOriginally posted by nanok Quote
i don't have the means to measure that though (i would need an osciloscope, i wouldn't even bother using a multimeter, or am i missing something?)
A digital multimeter (or an analogue one with high internal resistance) will be fine. You are interested in the trigger voltage which is present between the SYNC (middle) and GND (side) contacts of the hot-shoe mount of a flash constantly as soon it has charged up.


QuoteOriginally posted by nanok Quote
i don't think i do know. very interested
This was a problem of the CTR-301 receivers where some flashes wouldn't fire at all and others not sync above 1/30 shutter speed.

The fix was to add a wire between the receiver hot-shoe GND and the battery GND. Explanation:
QuoteQuote:
Here's what I think is happening with your mod. That little black chip that we think is an optoisolator driving the hot shoe in the CTR-301 receiver is actually a bridge rectifier, not an optoisolator. It's marked HD08 on my receiver and I looked up the data sheet. So it's there to handle the flash trigger voltage, no matter the polarity. Adding the extra ground wire to the hot shoe kills a diode drop in the bridge rectifier and allows the trigger circuit to work.
Apparently, there is a more in-depth modification that someone found necessary to apply.
12-02-2009, 01:01 AM   #68
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gnd to battery minus is exactly what i did. thanks for the links, i'll certainly have a look!

12-02-2009, 04:00 PM   #69
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it seems the problem is an integrated diode bridge, it sounds to me the soultion would be looking up an equivalent one, but which support lower voltages as well, to fix this issue "the nice way" instead of "the hackish way". or am i reading this wrong?

nice information nevertheless, thanks a lot class a, saved me a lot of trouble
12-02-2009, 04:22 PM   #70
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QuoteOriginally posted by nanok Quote
it seems the problem is an integrated diode bridge, it sounds to me the solution would be looking up an equivalent one, but which support lower voltages as well, to fix this issue "the nice way" instead of "the hackish way". or am i reading this wrong?
Not sure if such a "proper" modification exists for this design.

Glad I could help.
12-06-2009, 01:57 PM   #71
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update on the "phottix aster" receivers: did the modification with the battery minus connected to the gnd of the hotshoe (outside of shoe). they work well, except for a thin stripe at 1/180. will have to bypass the bridge altogether, hopefully that will solve it. they seem quite reliable otherwise, haven't had the chance to play with them as much as i'd want though.

i am not sure changing the rectifier bridge will help, it seems the voltage drop will happen anyway, and it's the circuitry behind the bridge (the radio receivers triggering circuit itself) which cannot handle such low voltage, if that's the case, save from redesigning the receiver, bypassing the bridge seems the only reasonable solution. i was also considering raising the voltage slightly, but i am not sure the triggering circuit inside the pentax flash itself would find that amusing..
04-06-2010, 05:26 AM   #72
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QuoteOriginally posted by nanok Quote
... bypassing the bridge seems the only reasonable solution.
That definitely works!
04-06-2010, 07:52 AM   #73
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QuoteOriginally posted by Class A Quote
That definitely works!
Did that, and works wonderful!
12-11-2010, 01:55 AM   #74
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Bumping

I got my set yesterday! And im quite impressed by them.
They are not crappy in their build, but not built like a tank either.
PW's and their likes are built better........but why the hell compare

So heres some pics.

As mentioned before. The packaging leaves nothing more to ask for. Good.




Its possible to use the receiver as a foot for the flash, and it works with the 540. But if i turn the flash head to the side, it will fall. With smaller flashes its probably more stable.


Test shots. These are not exactly impossible to do with the wireless system on the camera. But i had the flash out of the cameras line of sight and kinda hidden behind me, so it may have been difficult to achieve the same result with the built in flash controlling the 540.



This was taken through my apartment. From the kitchen through the hall and into the living room. Theres alot of walls and doorways. The flash was placed on the floor in the living room. Distance from camera is about 8-10 meters.
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