DS125 and ys25dx

I'm going to YAP in a few days, I have an Ikelite 20d and 1 DS125 ( Second Crashed ) Additionally I have a Sea&Sea ys25dx i plan on using as a fill flash since I cant shoot with 2 125s.

The YS25DX will be set in Optical Slave. and will hopefully work without the optical sync cord. I have one but it works without on land aswell just using the sensor in the flash body.

I am hoping this combination will work. I realize I will have to adjust TTL down to make up for the fill.

I realize this is an odd combination.

What are your thoughts on the ys25dx as a fill?

Cheers

Bill Russell

Hi Bill,

Are you using the DS125 as an eTTL strobe with either the Ike housing, or an eTTL converter? If so, the YS25 will need to be set up for preflash.

If you're just using the DS125 as a manual powered strobe, then use the YS25 as a straight slave.

It should be no problem. I'd use the diffuser on the YS25 for sure. It should provide some good fill.

Cheers

James

From someone that hasn't "seen the light" yet, can you explain what you mean by "providing a good fill". Is the second strobe trying to get rid of a shadow cast by the first, widening the cone of light or something else. How much of a bummer is it to have a single strobe?

Thanks!

Bart

Fill is just that, Bringing the exposure overall up. This provides 3 benefits.

The main strobe doesn’t have to work as hard.

The shadows are reduced

and the angle of light is increased.

Unfortunately the YS25dx is only good for the first 2 since the guide number is only 15 underwater compared to 30+ for the 125. However for reducing the shadows I figure it would be good for 2+ stops. That’s Fstops for light.

As for just using a single strobe. Start out with that. There is no need to over complicate your experience. 2 strobes will primarily give you a wider angle. But one strobe with a defuser will as well. It will just loose 1 or 2 Fstops of lighting ability. But with a good powerful single strobe it is usually not a problem except at the extremes.

As for fill, 1 strobe (defused) for fill on a slave ( that’s a flash that is fired by detecting the flash of a primary ) combined with a good primary should provide some good shadow control. The only drawback of a slave as apposed to a TTL secondary is that the TTL of the primary must be adjusted down to take into consideration the added light of the slave.

This is because when the primary fires in TTL mode it emits a preflash ( very briefly ) that is used to determine the over all primary flash amount. Because the slave should be set to fire only on the exposure flash ( the second burst of light from the primary ) the slave will not fire on the preflash; therefore the camera emits a full TTL charge for the primary with out regard for the added light the slave is bringing to the party. QED

Needless to say, This combination only works with a Slave that is fully manual. and a Primary TTL that can be adjusted to compensate for the slave.

Cheers..

Bill Russell

Thanks that makes a lot more sense now. I just ordered one Ikelite DS50 today and I'm glad to hear that one is ok to learn the basics and get decent shots. I was initially aiming for the DS125 but they have evaporated in all stores that I checked and won't be available until after I'm en-route to Cuba. After I gain hands-on experience I can see if I want to add a second DS50, something more powerful or just keep it at one.

All my lenses are f2 to f2.8 so I hope that also helps me cope with a less powerful strobe. Moreover, because it bundles its light in a narrower cone it is pretty bright and should be a good fit for my 35mm and longer lenses. The 15mm fisheye will probably be too much, but I can use magic filters on that one for now.

Thanks again,

Bart