Can I mix a DS-51 and a YS-90DX

[under water]

I have (or soon will have) a G9 in an Ikelite housing with a DS-51 hooked up via TTL sync cord. I also have a YS-90DX TTL Duo that I would like to use in slave (cordless) TTL mode.
The only concern I have is that the YS-90DX manual states that in the cordless TTL mode "the master strobe's guide number must be equal or higher than that of the YS-90DX. (If it is less, the YS-90DX may not yield correct exposure)"
The guide number of the YS-90DX is 22 & for the DS-51 is17. The YS-90DX is reduced to 16 if the diffuser is used.

Am I doomed to having overexposed shots when I use them both in TTL mode?
Can I get around this by using the diffuser on the YS-90 and not the DS-51?

Also the DS-51 puts out 5700 degrees Kelvin light and the YX-90DX is 5100 +/-300 Kelvin with diffuser.
Will that be noticable or be covered up by the fusion of the light?

Thanks!

 

[marcaumarc]

Can I piggyback on this question? I just got at d90 and I will be getting housing, etc. for it. Would it be possible to use my YS-27 in combination with another strobe, so I would only have to get 1 new strobe? I've never had ttl, so I don't necessarily think I would need it.

 

[under water]

Can I piggyback on this question? I just got at d90 and I will be getting housing, etc. for it. Would it be possible to use my YS-27 in combination with another strobe, so I would only have to get 1 new strobe? I've never had ttl, so I don't necessarily think I would need it.

In your case you can always use two strobes in manual mode, which is needed with the YS-27 anyway (I have one of those and like it). You just need to adjust them accordingly. The gist of my question was about cordless TTL mode and how effective that would be.

 

[Cathy Church]

All you have to do to adjust the ratio between your two strobes is to move one closer or further away from your subject, and/or (as you already noticed) use a diffuser. If both strobes are working as TTL strobes, as the 90DX should be doing) then the power difference will not matter. The camera will shut both strobes off at the same time, and the more powerful strobe will simply have contributed more exposure during that time than the weaker one. Keep track to use your weaker one for fill. If this doesn't help, let me know.

 

[under water]

All you have to do to adjust the ratio between your two strobes is to move one closer or further away from your subject, and/or (as you already noticed) use a diffuser. If both strobes are working as TTL strobes, as the 90DX should be doing) then the power difference will not matter. The camera will shut both strobes off at the same time, and the more powerful strobe will simply have contributed more exposure during that time than the weaker one. Keep track to use your weaker one for fill. If this doesn't help, let me know.

Thanks Cathy,
The setup seems to be working fine in test shots on land. TTL seems to work out OK and I like the fact that I can even manually control both strobes together by adjusting the manual settings on the DS-51 and leaving the 90DX in slave - TTL mode.
I can't wait to get it underwater.
BTW We are mulling over plans for a trip to Sunset House sometime this year. We checked it out last April while staying at Cobalt Coast. It sure looked like we would have been able to get many more shore dives in on your side of the island due to some weather that came in from the north/east.

 

[Cathy Church]

Quote: Originally posted by Frank DeLargy : "BTW We are mulling over plans for a trip to Sunset House sometime this year. We checked it out last April while staying at Cobalt Coast. It sure looked like we would have been able to get many more shore dives in on your side of the island due to some weather that came in from the north/east."

You are right. I am shore diving today with my brother and his family. Plus--you will be right next to MY SHOP and ME. Hoo Ray!