Inon Z-330 S-TTL troubleshooting

I've been shooting underwater for 10 years with a pair of Inon S-2000s on Olympus cameras (currently EM5 Mk 3) in a Nauticam housing triggered optically. Because I'm a relatively infrequent diver (once or twice a year) I've always used the strobes in S-TTL mode which has always worked brilliantly for me and is so simple. The S-2000s in S-TTL have been brilliant. I'm off to the Galapagos in a few weeks so decided to upgrade to the new Z-330 in anticipation of seeing some big stuff. I assumed the S-TTL would work just as well. However, I'm having huge problems. Either they give massive overexposure (ie total whiteout) or massive under-exposure. I've never had this before. I'm using the same optical leads that work for my S-2000s. Can anyone suggest any solutions? I know many will just say use strobes on manual! But, S-TTL works for me.

Are the magnets in or out? They need to be out for TTL...

The Z-330 has a button for that which should be out and is out.

That's the one and indeed they should be out. Even though they are a button, they are still known as magnets...as that is what they are

How are you producing the optical signal?

Adam

I'm using the flash on the EM5 with optical cables to the strobes.

I think we need more details. 

• I assume you have tested the current camera with the S-2000 in TTL and it has worked, please confirm
• What settings were you using on the S-2000 when they worked - dial positions
• What settings are you using on the Z-330 (dial positions)
• When you say the S-2000 worked well was that in macro or wide photography
• What camera/flash  settings are you using?

I have an EM-1 MkII with INON Z-240 I found TTL unreliable and now use manual flash 100% of the time.  If you are talking about big animals in the Galapagos, that is probably one area where you'll find TTL will struggle.

Hi. Great questions!

Yes, I've tested both today in the same room, same light conditions, same optical leads, same camera settings. S-2000s work great.

• I have the S2000 in S-TTL with the EV switch to B, right in the middle. I've never changed this. they have always worked great in Macro and wide (obviously, their limited power sometimes falls short in wide).
• I have the Z-330s set to S-TTL, magnets out, EV switch set to B. I've tried moving the EV dial up and down 3 or 4 places with little change.
• I did all these tests with the EM5 Mk3 in Manual, 1/125, F8, ISO200, fill flash on so the camera settings were always the same.

I also yesterday repeated the tests and swapped the optical cables around. This definitely changed the results so I'm wondering if I should get new optical cables. I had assumed that the optical cables were binary - their either worked or they didn't as they were just triggering the strobes.

This is hard to troubleshoot remotely without seeing the results of your tests

Can you define what you mean by the S-2000's "work great"?
Does this mean that you see a constant exposure at a range of apertures? 

@ChrisRoss's comment about TTL and lighting big scenes and/or big animals is also bang on the money. It will just offer a full dump all the time as the subject:flash distance is too great to offer any other TTL information. I think you will find manual strobe output control to be much simpler than you perhaps imagine...

Agree with Adam, manual is not that hard, set it at about half power or so and fire away.  You can tweak your aperture up and down a little as well as adjust the flash power.  Realistically flash range is 1-2m at most and the difference in flash power is two stops between those distances. 

As far as cables go they can make a difference generally less so with an INON flash being triggered by the accessory flash, but it's possible better cables may help.  TTL is more sensitive to cable quality as the strobe needs to match the duration of the onboard flash quite precisely.

Just to underline what Chris and Adam say, I used to be a big TTL fan with a Nikon D300 and Inon Z240 strobes.

But I've now gone away from that and using strobes on Manual is no big deal. I wouldn't lose too much sleep if you're struggling to get TTL to work - but it does work if set on Manual.

Thanks everyone. I had a great chat with Steve Warren at Inon UK and he suggested the optical cables might be the problem. I bought new Inon optical cables which seems to have solved the problem! Fantastic support from Steve at Inon UK.