UW technics flash trigger issues

[clavell]

Anyone having issues with a delay in the flash firing using the UW Technics flash trigger + sony a7r iv + backscatter mini flash II? or the equivalent? I have read and reread the instructions from UW technics, and gotten the correct dial setting for the mini flash II on the UW technics dial for different brand of flash settings, and when testing the setup, and using it in the water, have experienced a delay in the flash going off when I press the shutter button, making the photos unusable...any suggestions or experiences to share are appreciated. Cheers

 

[Barmaglot]

How long a delay? If I understand correctly, MF-2 only supports Olympus RC-TTL, so with a Sony camera, you need to use it in manual mode, WL flash on in the menus - this will cause the trigger to emit a single pulse, obviating pre-flash cancellation and eliminating pre-flash delay.

 

[Nemrod]

Yes. With my Sony A6400 and NA6400 with three different UWT triggers, five different kinds of strobes and two different A6400 cameras widely separated by serial numbers. Yep.

But in your case it might be incorrect set up of the strobe to match the trigger. Can you revert to manual for the strobe, disable preflash for the strobe, set trigger to 0 setting which is for my triggers a universal manual, no preflsh.

 

[Barmaglot]

disable preflash for the strobe

FYI, the Backscatter Mini-Flash (and its close cousin, AOI Q1) doesn't have manual pre-flash cancellation, instead, it has a learning mode - every time you power it on, it waits for a triggering pulse or a sequence thereof, and if there is more than one (some cameras have several), it remembers to only trigger on the last one. While in this learning mode, it will not flash at all; after it finishes learning, it will flash on the last pulse in what it considers to be your flash sequence. It is possible to confuse it by taking several test shots in rapid succession - you might not have a pre-flash at all, but it would learn that you do, and then when you proceed to shoot, a portion of your triggering signals will be ignored.

 

[Nemrod]

Yes, it has a learning mode instead of a physical switch to set the pre-flash or no pre-flash. If the board is set to the 0 setting there should be no pre-flash emitted by the LEDs on the camera side. The A7R, unlike the APS-C models, does have internal manual strobe mode (?) and if I am correct that then set the camera to manual strobe mode, the board to 0 and set the strobe to no pre-flash (let it learn that mode). Thanks for your clarification.

 

[Barmaglot]

The A7R, unlike the APS-C models, does have internal manual strobe mode (?)

Not quite. The divide is more between older and newer menus, not between crop and full-frame. In the older cameras, such as my former a6300, the flash setting was auto/slow/rear/wireless; in the newer models, such as a6700, WL flash is a separate on/off setting. When WL flash is enabled (on newer cameras) or flash is set to WL (on older cameras), it operates in manual mode, with no pre-flash. This only applies to flashes connected via the hot shoe though (and possibly PC socket, I don't have an A1 so I don't know), not to the built-in/pop-up flash - that one always emits a pre-flash, and if an external flash is not connected, the WL flash option is greyed out. Of course none of the full-frame Alpha cameras have a built-in flash, so for them it's a moot point, but a crop camera with a connect flash (or trigger) will operate just like a full-frame one. There is no need to set the board to '0', and in fact it's possible to switch between manual and TTL (provided the strobes support it, which is not the case with MF-1/MF-2) during a dive, without unsealing the housing.

 

[clavell]

How long a delay? If I understand correctly, MF-2 only supports Olympus RC-TTL, so with a Sony camera, you need to use it in manual mode, WL flash on in the menus - this will cause the trigger to emit a single pulse, obviating pre-flash cancellation and eliminating pre-flash delay.

The delay is est. 2-4 seconds. I shoot in manual mode. The flash menu is set up for wireless flash that allows the camera and strobes to fire at a higher shutter speed than the usual limiting 1/250, in theory. The delay occurs regardless of the shutter speed setting however. I have spoken with the guys at Backscatter who have confirmed that the UW technics does work with the sony camera, but this delay remains a mystery. Thanks

 

[clavell]

Yes. With my Sony A6400 and NA6400 with three different UWT triggers, five different kinds of strobes and two different A6400 cameras widely separated by serial numbers. Yep.

But in your case it might be incorrect set up of the strobe to match the trigger. Can you revert to manual for the strobe, disable preflash for the strobe, set trigger to 0 setting which is for my triggers a universal manual, no preflsh.

Thanks. The flash is always set for manual, except it is supposed to be set for “HHS” for use with the UW technics flash trigger i believe. There is no preflash from the sony camera, and I am also aware of the flash “learning” each time I turn it on and do a test flash, per the manual and the advice from the team at Backscatter. So, it may not fire for the first test shot, but that may be normal, and just wait a few seconds before doing a second test shot when testing the rig for proper functioning. The Backscatter team also said to set the trigger dial for 7 for the MF II, which I have done also.
Maybe resetting the dial to 0 on the flash trigger and retesting will somehow get it firing correctly. Thanks again

 

[Barmaglot]

The flash is always set for manual, except it is supposed to be set for “HHS” for use with the UW technics flash trigger i believe.

AFAIK you should only set the strobe mode knob to HSS when the camera is in HSS mode. If your A7RIV behaves in the same way as my A6700, you should see 'HSS' next to the flash lightning bolt symbol when your shutter speed exceeds normal sync speed (1/160s for me, should be 1/250s for you). The triggering signal for HSS is very different from a regular pulse. I don't have an MF-2, but with my Retra Pro, if I have the camera in HSS mode but the strobe in regular flash, it will fire out of sync, and vice versa.

The delay is est. 2-4 seconds. I shoot in manual mode. The flash menu is set up for wireless flash that allows the camera and strobes to fire at a higher shutter speed than the usual limiting 1/250, in theory. The delay occurs regardless of the shutter speed setting however.

Very strange; normally such a delay would be associated with a long exposure + rear curtain sync, but evidently that is not the case. Does the delay occur at the trigger or the strobe, i.e. if you look at the LEDs, do you see them flashing 2-4 seconds after you pull the shutter, or do the LEDs fire immediately and then the strobe firing is delayed? Do you have a regular land flash you could put on the hot shoe and test with?

 

[Nemrod]

^^^What he said^^^

Take your strobe out of HSS mode and set to it to manual mode by whatever means is correct for that strobe. Set a shutter speed less than 1/250 on your A7R. Try something simple like 1/125.

Your camera should shift from normal X-sync to HSS sync when your shutter speed exceeds (your X-sync) speed of 1/250. But I do not think your strobe has any idea about what shutter speed is selected. If you intend to shoot HSS at 1/500 second you will need to set your strobe to HSS mode for speeds above 1/250.

Set your camera shutter to first/front curtain and turn off e-shutter if selected.

Do the test Barm suggests by looking at your strobe and camera with one of the sync cord ports open facing a mirror in a dim room. You should see the led in the open port and the flash fire at the same time in the mirror and in photo review you should clearly see a bright flash and the led in the photo. If not, we got a problem Houston .

Shutter speeds much above 1/125 underwater are not used often, it is luxury to have a 1/250 X-sync and an option to play with HSS but the vast majority of your photos will be done at under 1/250 and probably closer to 1/125 for general shooting dependent upon ISO, macro, CFW, WA, f-stop, ambient light and strobe power setting and all of that other stuff that separates photographers like @Barmaglot from picture takers like me .