Possible to use Ike strobe TTL, + YS-90DX slave?

I just took my first trip with a Nikon D200 in an Ikelite housing. I was using 2 Sea & Sea YS-90DX strobes in manual mode.

I'm thinking about an Ikelite strobe to use via TTL with the Ike housing, but don't want to buy two ($$$), and would like to use one of my YS-90's as a second strobe to reduce shadows. Would it work to use a cord for the Ike strobe TTL, but use a 90DX as slave, and set the Ike housing circuitry at -1.5 stop down?

Someone pointed out to me that using a pair of Ikelite strobes would have an advantage even in manual mode: the housing allows one readily-accessible knob to adjust dual strobe power as much as -3 stops. This could be a lot easier than twisting a knob on each strobe!

I tried slaving a YS30 off a Ike strobe on TTL and it fired on the pre flash instead of the main flash, I don't know if the YS90DX has a setting to ignore preflash.

I tried slaving a YS30 off a Ike strobe on TTL and it fired on the pre flash instead of the main flash, I don't know if the YS90DX has a setting to ignore preflash.

Yes, the YS90DX can be set to ignore the preflash. That's how I imagined it coudl be used here. That means of course that the Ike electronics would adjust the Ike strobe without the S&S, so I supposed setting it to underexpose, and using the YS90 as fill might work...

In maual mode if you can set the YS90 to slave TTL you should be able to control the power of both strobes via the housing control. If the main strobe fires at 1/2 power the slave should fire for the same duration so also less than full power.

In TTL I think you'd probably have to dial in some underexposure as the flash exposure is calculated from the preflash which wouldn't allow for the second strobe, I think the best solution is to try it and see what you get.

With wide angle it can be difficult to get the slave strobe to fire reliably. Pointing it slightly towards the main strobe helps but is more likely to create backscatter. I did consider using a fibre optic connection from slave to main strobe but gave up because of the preflash problem.

I tried this exact setup 1 month ago in Kona. Although you can definitely get the YS-90 to fire by setting it to "slave", it really doesn't work well. The YS-90 is much weaker than the DS-125 and you'll either get a huge overexposure from the DS-125 side or the entire shot will be underexposed. I tried it on several dives and tried setting under/overexposure on my TTL housing, tried +/- in-camera and tried all the different settings on the YS-90.

In addition, if you split the flashes too wide, the YS-90 won't see the DS-125 go off and won't fire. Being in remote detection TTL mode, the YS-90 kept going off anytime another diver took a picture. I had the best results going to manual mode, setting the YS-90 on "10" and the DS-125 on "1/2" and I stretched the optical cord over to the DS-125 to trigger the YS-90.

Pretty much waste of time in my opinion; I used it for one day and then went back to my single DS-125. In the end, the photos from one strobe were all better than any of my attempts with the slaved YS-90. I'll just buy another DS-125 for the next trip

YMMV,

JP

Thanks, JP! This is exactly what I was looking for. I was pretty sure it would "work" (i.e. both strobes would fire, the Ike would act TTL), but not at all sure it would actually perform with the advantages I hoped for.

It's not what I wanted to hear, but it's cheaper to learn from you than to try it myself... so thanks again.