A6400 with FA6400: missing pieces to complete :) please advise!

• Electronic synch cord (via m16 bulkhead)
• Fiber optics via built-in flash using fiber optic cables
• Fantasea FA-1 LED Strobe Trigger, but if I read correctly only manual mode work Fantasea FA-1 LED Strobe Trigger

• Via electronic synch cord do I get both TTL and manual?
• Via optical fibre cords? Will the fast recycle time of D3 be limited by the internal flash? Do I get both manual and TTL?

Thanks a lot! 

Welcome to the Sonyside....

I have a FA6500 and YS-D2js so will cover some of that first.

I use the LED trigger as the inbuild flash will only sync to 1/160 sec, the trigger gives you 1/250sec...

However..

I'm interested if the YS-D3 has an improved sensor as I found the sensor with the LED flash trigger and commerical fibre optic cables to be unreliable to say the best!!  I've tried multiple cables from top end to cheapo's and various thread counts.. the most realiable option was to make my own out of 2/3mm side light fibre (also about 1/10 the cost of most cables)...  This allow me to be sure the strobes fire.

Commerical cables mostly work with the internal flash but limits the sync speed and burns far more battery.

If you go the sync cable route you will obviously need the cables and the hotshoe controller, which will add to you budget considerably, and Fantasea I don't believe do one so it will be third party.

I thought of sync cables, but also have a backscatter snnot stobe and that's fibre only.

I use the Tonika 10-17 for wide angle and it works really well.. I run the Sea and Sea acrylic dome which is slightly lighter and larger than the  Fantasea one, but also bought float arms but they are pretty float with a dome on (i.e. positively bouyant), there is a lot of air space with the port and extension ring (I run the 20L extension but thats for the 10-17mm or my 90mm Macro).

 The float arms I mainly find useful with the 90mm as its a beast, or if I use the kit and my old UWL-09F wide angle, then they help.

The mix of 8 and 5 inch arms should work fine, and I'd buy the Dome Diffusers later as they come with 100 and 120 ones.

I would also recommend you get the standard kit lens set from Fantasea as it can also be a good way to get into the base macro and is pretty cheap.

I hope this helps

If you are LED triggering go for the INON strobes instead - far less problems getting them to trigger and they are cheaper - I'm very happy with my INON strobes.  I would get them LED triggering or not.

You could start out using the onboard flash and see how you go - the downside is Sony don't have a manual strobe option and the sync speed issue.   There are a number of options for LED triggers - you could ask specifically for recommendations in the strobes and lighting forum.  There are options for manual or TTL boards - Fantasea make a manual only trigger - UW technics make a TTL trigger but not specifically for the Fantasea housing.

Note I'm not sure you can get higher than 1/160 flash sync with the A6400 - the full frame bodies allow it when an external Sony flash is attached and LED triggers cam  mimic this. You might get a little better than the published speed with a trigger depending on how quickly the flash responds. 

For buoyancy arms you need to know the weight of what you have in water - it will be different with dome vs macro lens and the data is usually not published - not helpful I know,  but you don't want to be positively buoyant and this means unless you find someone who has your exact combination you need to weigh it in water yourself and choose the appropriate amount of buoyancy.  I use a luggage scale and suspend the rig in a tub of water - getting it to submerge completely - fresh water is fine as you normally leave the rig slightly negative and the change is only 3% for salt water.

To use your arm you need to choose a tray - You could use the tray you have with the ball adapters.  Ultralight have a very good name for arms/clamps , look here:  https://www.bluewaterphotostore.com/underwater/accessories/arms-trays

 For strobe arms you can start with a 5" and and an 8", or order everything but armsand weigh your gear in water using a luggage scale to calculate how much buoyancy you need.  The INON float arms are pretty good:  https://www.bluewaterphotostore.com/underwater/accessories/floats-float-arms

Just to add to Chris’ advice, it’s worth looking at Stix floats for adding buoyancy. They are a type of solid foam which are relatively easy to slide on to Ultralight (ULCS) arms, which are excellent, and are highly adaptable. 

The A6xxx series flash is slow to recharge and cannot be adjusted down so I would avoid using it to fire strobes.

I personally also would avoid electronic sync cords, as they're expensive and an additional failure point, and TTL triggers have made them obsolete.

While the fantasea LED trigger is manual only, there are plenty on the market that can do TTL.

I use the TRT electronics trigger with my YS-110a's, and TTL works perfectly. (s-TURTLE SMART)