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10-10-2016, 03:31 AM   #1
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Acon R930 P-TTL radio trigger and 2 flash setup, what flash do i need.

Ok, here is the thing.
I have: 540FGZ flash, a camera, Acon R930 transmitter, and 2 recievers.
For now, i'm using single off camera flash setup. I'm always using P-TTL and never go manual in flash settings, because P-TTL is providing good results each time.
I have a plan to get second flash, to use more complicated light setup.
The problem is, i can not decide, should i get P-TTL flash, or just any flash, and go manual on it?
For instance, i use 540FGZ as main light with P-TTL, and second flash for hair light. Would the second flash mess things up if it also will be in P-TTL mode? Or i will just use exposure correction to make it less power?
Another instance, i'm planning to shoot a party, and usually i put my single flash with small softbox somewhere to cover whole room, and P-TTL does all work for me, if i will use 2 flashes, 1 of them with no P-TTL, what results will i get? One with manual mode will fire designated power, and P-TTL will adapt each time, i assume? Or, because P-TTL use pre-flash to meter exposure, the manual flash will mess things up, because it will fire with main impulse from P-TTL flash, and exposure done with pre-flash does not considering this?

10-10-2016, 04:21 AM   #2
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No, the manual flash will not affect the P-TTL exposure, because the pre-flashes have occurred before the main flash output. The power of this is already decided and fixed and the manual flash will simply add it's light to the scene 'on top of' the P-TTL exposure. The P-TTL system will be unaware of the manual flashes existence.. You will obviously have to account for the extra light being added through the normal ISO, aperture, flash zoom settings and the distance.

---------- Post added 10-10-16 at 11:23 ----------

So long as your manual flash is radio triggered then it will fire on the main exposure and not be interfered with by the pre-flashes.

---------- Post added 10-10-16 at 11:25 ----------

Regarding the issue of 2 flash wireless P-TTL with the Acon triggers ... Well, you may end up being the one who has to come back here and tell us how it all works ....

Last edited by mcgregni; 10-10-2016 at 04:29 AM.
10-10-2016, 06:22 AM   #3
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Guess, i'l have to borrow P-TTL flash and make some tests...
10-10-2016, 01:20 PM   #4
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I look forward to hearing how it goes! To be frank, the amount of consistent and clear information I've been able to discern from posts around here, especially relating to the control of multiple P-TTL slave flashes using the Acon triggers is, ...well,... patchy. I'm not sure if we can safely assume that the features and functioning is the equivalent of a 2 flash P-TTL optical wireless setup, but with radio remote control. I can't say that I understand if there is any degree of independent remote control available from the trigger device, whether global flash compensation from the camera control would work .... These are some obvious first questions that occur to me.

10-11-2016, 08:04 AM   #5
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Ok, a guy came to me at work with Metz-58. While he had his coffee, i had some time to play with triggers and flashes. (i have AF 540 FGZ and K-S2 with Sigma 17-50 2.8)
Both 2 flashes in P-TTL mode - works, sort of. Sort of - becasue if you change any settings on camera, or just go to "play" mode to watch photos you just took, something goes wrong, and next picture is overexposed, and keeps staying that way.
One flash in P-TTL mode, and 1 manual - works only the P-TTL one. (which is weird). Both flashes trigger, but only one in P-TTL mode visible on picture.
Both flashes manual mode - for some reason this did not work at all, because 540 did not wanted to switch in manual.
Both flashes in A mode - works ok, exposed correctly.
We did another test, put Metz on top of transmitter unit, that sit on a camera, and 540 was on reciever unit. Both flases trigger, but only 540 light is visible on picture.
I borrowed Metz flash for deeper testing at home, and we will try to test with 2 540 flashes in thursday.
Guys, if you have some ideas about testing, it is right about time for you to tell me.
10-11-2016, 12:47 PM - 1 Like   #6
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I made some more tests. For now, it is clear that two P-TTL flashes from different manufactures can not work together on Acon triggers. Only usable results are with 1/125th shutter speed. It is even noticeble that flashes do not fire right in the same time.
Need more tests with flashes of same manufacturer.

P.S. I've also tested "manual power control" mode of the Acon transmitters. Mine is only v 3.0 firmware, so it is only mode available to me. But it works, and works ok, but you can not control power for each flash, they act like one.
10-11-2016, 06:08 PM   #7
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Thanks for the updates and the testing .... It does sound disappointing so far. Am I right to assume that single flash P-TTL works ok with both the Metz and Pentax flash? It's just when you combine the two that things are going wrong?

I must admit I have not ever tried to mix one P-TTL slave with one manual mode one, not with normal wireless optical triggering .... I've only used the 2 slaves both in P-TTL, so I'm not even sure it this mixed mode approach is valid for the Pentax system. Perhaps someone else will know, as it may be unfair to blame the triggers for this particular issue .....
10-12-2016, 12:20 AM   #8
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QuoteOriginally posted by mcgregni Quote
Am I right to assume that single flash P-TTL works ok with both the Metz and Pentax flash? It's just when you combine the two that things are going wrong?
absolutly. single P-TTL works fine.

10-12-2016, 11:59 AM - 1 Like   #9
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I've made more tests today.
I managed to get things working in P-TTL, sort of... Both flashes must be in same mode: for me, rear curtain worked. And both flashes must be in -2.5 EV compensation, to get right exposure.
I hope i will have a chance to make a test with 2 AF 540FGZ flashes.

p.s. Acon recievers eat batteries like hell. They discharge faster, then batteries in flash. I did not noticed that in regular use (i'm not heavy strobe user).
10-12-2016, 03:20 PM   #10
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It doesn't sound very encouraging. I wonder if you have the best firmware for that 2-flash P-TTL purpose ? I know there are different firmwares around for the Acon units, but I'm not sure whether you can change the firmware on the same units to give different functioning .... ?
10-13-2016, 12:32 AM   #11
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QuoteOriginally posted by mcgregni Quote
I know there are different firmwares around for the Acon units, but I'm not sure whether you can change the firmware on the same units to give different functioning .... ?
Yes, you can change the firmware on the same hardware, for example to switch a unit from P-TTL to i-TTL.

QuoteQuote:
A receiver can be updated with firmware of Acon R930PN (Pentax to Nikon), The receiver can hol
d a normal Nikon flash or a Nikon radio trigger. allowing multi-brand HSS. or both update to the
R930N firmware, make it an i-TTL trigger. A Canon flash also can be added to this system.
(Note: some earlier R930 may not have hardware for Nikon &.Canon)
They have published a IMHO better (clearer) v5.1.6 manual: http://acon-photo.com/?wpdmdl=269
10-13-2016, 12:42 AM   #12
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I can not update software, because i dont have a cable for that. it was not included.
10-13-2016, 02:53 AM   #13
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QuoteOriginally posted by GraySaint Quote
I can not update software, because i dont have a cable for that. it was not included.
Mail them and ask them when they will send it to you.

It is part of the kit, see they photo: http://acon-photo.com/wp-content/uploads/2015/05/IMGP8308.jpg on the right side.
10-13-2016, 04:37 AM   #14
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alredy did. no ansver, though
10-14-2016, 07:03 AM   #15
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Final update: 2 AF540 FGZ flash units failed to get stable results in P-TTL mode. Some shots overcast, some not. Also, seems one of my recievers is broken, batteries in it discharge very quickly, and it turns off with no reason. And it did not saw much use, what a shame.
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