Leaf shutter fires flash twice(opening and closing)? rz67 w/ modern flash&triggers

[Qiuhong]

Hi, I've ran into issues again trying to find a Speedlight system for my rz67

The Issue: My RZ67 fires flash twice even to 1/250s, once when the shutter is opening and once when closing.

This issue occurs:
-when godox and neewer modern speedlights are used on hotshoe
-when godox x1t trigger is used on hotshoe to trigger godox speedlight with built in receiver
-when connecting godox speedlight via PC sync cable to the lens

This issue doesn't occur (flash only goes off once, when closing):
-when using old vivitar 285 that recycles too slow to do a second fire at closing
-when using the modern speedlights at high power so they also can't recycle in time to get triggered a second time
-when using the more generic peanut trigger and receiver with the same modern speedlight that otherwise will fire twice

I initially wanted to use the godox x1t trigger with godox tt685ii speedlight to do on camera flash power adjustment for efficiency but this double fire seems like a big problem.
Right now the only solution to prevent double flash is to use high power slow recycle time and/or peanut triggers off camera, very limiting!

-Does anybody know why the leaf shutter fires twice?
-If I take a photo with the double flash, is there a chance that the rear flash goes off after the lens closes so it won't get recorded on the photo thus doesn't matter?
-Does anybody know a speedlight that doesn't have this problem when mounted on hotshoe on the RZ and has more power variable than the old vivitar (4 power settings only)

Please advice, thanks!

image shows the godox system (middle), vivitar flash, peanut trigger (which prevents double flash)

 

[MattKing]

I expect that the double flash relates to how long the leaf shutter synch maintains contact - the godox trigger is expecting something that stays closed for a shorter duration.

 

[BrianShaw]

Is it possible that there is something "camera unique" about the trigger that could be causing this behavior? I couldn't help but notice that the unit in the picture is specified as "for Fuji cameras" in the company web brochure, and other variants of that model seem to also be camera-unique.

X1T-F-Product-GODOX Photo Equipment Co.,Ltd.

Founded in 1993 as a high-tech manufacturing facility specializing in lighting and audio equipment, Godox has now become a lighting equipment expert and innovator of gears for photographers, videographers, filmmakers and more. Driven by the mission of offering great lighting and audio solutions...

godox.com

 

[cramej]

My $.02, FWIW.....I wonder if the Godox flash and triggers are far more sensitive to voltage changes over the sync circuit and could be causing it to fire twice. Older cameras and flashes use higher voltages to trigger and newer equipment is much less. It sees voltage rise and fall and isn't discriminating - the hardware is just looking for if V = change then Fire.

 

[Qiuhong]

Is it possible that there is something "camera unique" about the trigger that could be causing this behavior? I couldn't help but notice that the unit in the picture is specified as "for Fuji cameras" in the company web brochure, and other variants of that model seem to also be camera-unique.

X1T-F-Product-GODOX Photo Equipment Co.,Ltd.

Founded in 1993 as a high-tech manufacturing facility specializing in lighting and audio equipment, Godox has now become a lighting equipment expert and innovator of gears for photographers, videographers, filmmakers and more. Driven by the mission of offering great lighting and audio solutions...

godox.com

Not sure, the reason I bought the fuji is to use it with my mirrorless, maybe it was too good to be true haha

 

[Qiuhong]

My $.02, FWIW.....I wonder if the Godox flash and triggers are far more sensitive to voltage changes over the sync circuit and could be causing it to fire twice. Older cameras and flashes use higher voltages to trigger and newer equipment is much less. It sees voltage rise and fall and isn't discriminating - the hardware is just looking for if V = change then Fire.

interesting, if that's the case is there any solution?

 

[MattKing]

If the trigger is designed for dedicated use on a particular camera, you are probably seeing the result of using it on something else - that trigger isn't appropriate for this use.

 

[cramej]

interesting, if that's the case is there any solution?

I don't think so except maybe using an older dumb trigger, but.....

If the trigger is designed for dedicated use on a particular camera, you are probably seeing the result of using it on something else - that trigger isn't appropriate for this use.

I've had the same issue with dumb triggers in the past on a RB67. Then again, I've also used a SB-800 on non-ttl and non-Nikon cameras in A mode with no issue as well has having a flash trigger as soon as I put it in the hot shoe.

 

[Qiuhong]

I don't think so except maybe using an older dumb trigger, but.....

I've had the same issue with dumb triggers in the past on a RB67. Then again, I've also used a SB-800 on non-ttl and non-Nikon cameras in A mode with no issue as well has having a flash trigger as soon as I put it in the hot shoe.

This set up works for all my other film cameras just not the picky RZ, I also have a neewer speedlight that has the same issue, the only flash that works for now is vivitar 285v which is older and only has four power variations...

 

[maltfalc]

you can get more precise control of the 285hv's output by swapping out the vari power module for a potentiometer.

 

[reddesert]

It is possible the issue is switch bouncing, and that whatever the problem flashes/triggers are using to detect the circuit closing is more sensitive to bounce. I understand that you're saying the non-problem flash works because it has slower recycle time, but it might also be that the more modern flashes have a higher speed detection circuit than older ones did, and are more sensitive to bounce.

If I were trying to debug this issue, I would connect a low-voltage DC source (or the problem flash itself) and an oscilloscope across the sync contact to measure the voltage change as the shutter opens and closes and inspect the waveform to look for the voltage change and bouncing.

It may be possible to debounce the switch with a simple resistor-capacitor circuit. There are a jillion articles out there about debouncing, for example https://www.digikey.ee/en/articles/how-to-implement-hardware-debounce-for-switches-and-relays Many of these are focused on cleaning up a signal for input to a digital gate, and the flash trigger sense is more or less analog, which may make it a little easier.

 

[RalphLambrecht]

Hi, I've ran into issues again trying to find a Speedlight system for my rz67

The Issue: My RZ67 fires flash twice even to 1/250s, once when the shutter is opening and once when closing.

This issue occurs:
-when godox and neewer modern speedlights are used on hotshoe
-when godox x1t trigger is used on hotshoe to trigger godox speedlight with built in receiver
-when connecting godox speedlight via PC sync cable to the lens

This issue doesn't occur (flash only goes off once, when closing):
-when using old vivitar 285 that recycles too slow to do a second fire at closing
-when using the modern speedlights at high power so they also can't recycle in time to get triggered a second time
-when using the more generic peanut trigger and receiver with the same modern speedlight that otherwise will fire twice

I initially wanted to use the godox x1t trigger with godox tt685ii speedlight to do on camera flash power adjustment for efficiency but this double fire seems like a big problem.
Right now the only solution to prevent double flash is to use high power slow recycle time and/or peanut triggers off camera, very limiting!

-Does anybody know why the leaf shutter fires twice?
-If I take a photo with the double flash, is there a chance that the rear flash goes off after the lens closes so it won't get recorded on the photo thus doesn't matter?
-Does anybody know a speedlight that doesn't have this problem when mounted on hotshoe on the RZ and has more power variable than the old vivitar (4 power settings only)

Please advice, thanks!

View attachment 323115
image shows the godox system (middle), vivitar flash, peanut trigger (which prevents double flash)

That's one of the trick just imagine the possibilities!

 

[M Carter]

I can't answer the "why" of this (but try Bill at MamiyaRepair.com, he would know). But as far as the 2nd flash registering on film, that's the kind of thing you can test very easily. Do some tests on your next roll, or even cut some photo paper or ortho-litho film and stick a sheet in the back (or use the polaroid back if you have one). Come up with a way to see two pulses independently, like turning the camera when you fire it, so it's aimed at something that will show a single or double exposure.