Does anyone using the new Underwater Technics external flash trigger ? The one which goes un the M24 bulkhead ?

While it may provide better signal quality (according to UwT), i am concerned it may be too tall and cannot fit under the metal cross bar above the housing (Canon R5 and Marelux/Nauticam type).

Any though or inputs ?

thanks!

Cyrille, it’s worth dropping Pavel a PM and asking him. He could give you height details etc. he may well chip-in here of course.

First the new UWT external trigger is outstanding. I have been using it in TTL with the Marelux Apollo S strobes and it has been very accurate. I tested with a wide lens at ISO-50 from F/2.8 to F/22 and it was accurate across the full range of F/numbers. Past TTL solutions I have used over exported at F/2.8-F/3.5.

I have attached photos of the M24 UWT trigger mounted on the Marelux Sony A1 housing. I had to reverse the direction of the current crossover bar because it hits the trigger and can't be secured the grips. Reversed it slightly blocks the vacuum valve and as a result I could use a manual vacuum pump but not the power vacuum pump. After adding a grip extension and moving the bar to the left I am now able to use the power vacuum pump.

The A1 housing is advertised to be 126mm deep while the Canon R5 housing is advertised to be 149mm deep so each housing is going to be different regarding the crossover bar installation.

Also the new housings like the Sony A1 II have an M24 that is tilted outward about 15/20 degrees and this may help.

Phill, thank you for your research into this new product.

This is important information, both regarding TTL imaging accuracy and installation.

Also thank you for the photos of installation on the Marelux housing.

Edited October 5Oct 5 by Pavel Kolpakov

33 minutes ago, Pavel Kolpakov said:

Phill, thank you for your research into this new product.

This is important information, both regarding TTL imaging accuracy and installation.

Also thank you for the photos of installation on the Marelux housing.

I also have one mounted on the Marelux A7C II/R housing and no problems. Headed to Bali tomorrow for extensive testing of all features.

On 10/5/2025 at 10:41 AM, Phil Rudin said:

I also have one mounted on the Marelux A7C II/R housing and no problems. Headed to Bali tomorrow for extensive testing of all features.

We will be waiting for the test results from your trip to Bali.

Edited October 8Oct 8 by Pavel Kolpakov