Rear curtain slow shutter speed Sony with UWTechnics Trigger

[JB_Cazajous]

Hello
I use a UWTechnics flash trigger with a sony A7RIII and Nauticam housing
When I want to use my strobes to take slow shutter speed photos, I have a problem
I put my Inon Z330 strobes in Manual mode, rear curtain flash on the Sony A7RIII and below a speed of 1/15s it does not flash correctly
I explain:
For speeds of 1/15s and more, no problem, a pre-flash fires, then 1/15s  later the real flash appears on the rear curtain
However, from a speed of 1/13s or less, the flash on the rear curtain is very weak (like a second pre-flash) and does not sufficiently illuminate the scene to be photographed.

On front curtain it works well for any shutter speed

This problem appears only on rear curtain with speed under 1/13s
Do you have an idea to solve this problem?
Thanks you

Edited May 30 by JB_Cazajous

[FrancoisC]

Hi JB

did you set your Z330 to ignore the preflash ?
small button on right.

Push or pull, I do not remember...

Edited May 31 by FrancoisC

[JB_Cazajous]

Hello Francois

Actually the function of this button is not to ignore the preflash, but to let my Z330 understand if my camera is going to send a preflash to it.
If I activate it (button pressed) the Z330 will consider the preflash of my camera as the main flash
A black image follows.

[Chris Ross]

I would think the problem lies within the camera/UWT trigger combination.  When in manual the INON strobe just fires when it receives a light pulse.  You might be best to message Pavel if he doesn't chime in.

[JB_Cazajous]

After many tests, I finally found the solution!!! 😁

 

On the UWT trigger there is a small dial which allows you to configure the trigger according to the strobe you own
This one was on position 6 which corresponds to the Inon Z330 strobe
This allows you to use the Z330 in s-TTL mode, but it creates a pre flash

Switching this dial to position 0 completely disables TTL mode, but it also disables preflash

All I had to do then was press the preflash button on my Z330 strobes

No more rear-curtain flash sync problems below 1/15s

Edited June 2 by JB_Cazajous

[ChipBPhoto]

37 minutes ago, JB_Cazajous said:

After many tests, I finally found the solution!!! 😁

 

On the UWT trigger there is a small dial which allows you to configure the trigger according to the flash you own
This one was on position 6 which corresponds to the Inon Z330 strobe
This allows you to use the Z330 in s-TTL mode, but it creates a pre flash

Switching this dial to position 0 completely disables TTL mode, but it also disables preflash

All I had to do then was press the preflash button on my Z330 strobes

No more rear-curtain flash sync problems below 1/15s

 

Excellent news!  I have the same setup. Currently I have the UWT trigger set at 0 and use the Z-330s in manual.  If I want to change to TTL, this will be very useful information.  Thanks again!