Olympus OM-D E-M5 and TTL-Problems (Inon / Sea&Sea)

In another topic Rodd wrote "I've had issues with getting the TTL to work consistently. ..." Well, I had the same problems and changed to manual. However sometimes it would be just convenient to have a reliable TTL, for example if you play around with f/stops. Or if a shy creature retreats if you fumble with strobe settings.

Today I did a series of test shots with TTL. Before I started I used the small camera strobe alone (no housing) and an Olympus FL300R; with both strobes exposure was 100%perfect.

My test setup for the u/w strobes: Camera was set to "Fill" flash, no flash output compensation. I used spot, center weighted and ESP metering, I used low ISO and ISO 400. All pics taken with an Oly 60mm macro lens. I shot with an Inon Z240 Type 4 and with a YS110a, both triple-checked for the correct settings. And single strobe only to keep things simple. I used two different fiber optic cables, both 3rd party products.

My results: No reliable TTL results. Sometimes the pics with f/stops 2.8 were okay, sometimes completely overexposed, f/3.5 to f/7.1 were mostly okay, sometimes overexpossed; f/8 to f/13 sometimes okay, sometimes overexposed. In the range from f/14 to f/18 results were mostly okay, f/20 and f/22 were underexposed. (I checked- wIth manual output at f/22 the pics were completely overexposed, so the strobes had enough power.)

I changed the in-camera strobe compensation to plus and minus - this had little to no effect.

Then I remembered that I have an old Heinrichs-Weikamp TTL-Converter. So I used an electrical sync cord at the strobe and hand-held the converter in front of the housing strobe holes. Guess what - TTL was okay! In camera strobe compensation worked flawlessly. I could even get an old YS120 to work with perfect results.

But using this converter in the field is not a real option too bulky, and ofor one strobe only. What could I do to get TTL working with fiber optic cables? I am a bit reluctant to buy an expensive genuine Inon or Sea&Sea cable only to find out that this does not help... Any idea? Does it make sense to buy a THICKER TOS link cable (2mm) and use this with the connectors (should work if I strip off the coating)? Any other idea?

Thanks,

Jock

I have not tested as systematically as you have, but I seem to have no trouble at all with TTL. I'm using an EM-5 with two Inon S-2000 strobes and Inon fiber optic cables. I shoot mostly macro and almost always on TTL with spot metering, camera flash set to fill, no EV or flash compensation. I'm usually shooting in the f/16 to f/22 range but recently have been experimenting with wider apertures up to f/4,also with the Olympus 60mm macro. Looking back over the last couple of trips, I don't find many images at all with obviously wrong exposures, though of course some are not quite perfect but close enough that they are easy to fix.

It seems unlikely that the problems you experience could be due to the cables, but it should be easy enough to find out. Maybe you could borrow from a dealer, or test in their shop? One other wild thought would be to see if a firmware update changes anything - though I am just guessing here as I have no idea if that addresses something like metering. Otherwise I am at a loss for suggestions. Good luck!

It is not a fiber cable problem since the TTL signals rely on time not on power (for the most part). In my hands, I first tried the EM-5 at TTL with the built in strobe on land with pretty spotty results. Try the camera out of the housing and see how TTL works on land, it is unlikely to work better underwater.

Bill

Bill,

as I wrote, on land TTL works 100%: perfect exposure from f/2.8 to f/22. I tried with the small strobe that comes with the camera and with a more powerful FL300R. And with the Heinrichs-Weikamp adapter and a "hard wiring" to the YS110a (sync cable) TTL also works 99% (f/2.8 a little overexposed).

I double-checked the fiber cable endings, no dirt or whatsoever on them.

Very strange.

Jock

if you sit back and think about it... you have several different scenarios in the mix. the key question is "who" is really making the ttl decison? with multiple different systems you can expect to get different results.

you get good results with trusted systems and iffy results with others.

i have a set of YS110's (among others) and they are known as having poor optical triggering ability. they work great via wired sync cord. i claim this is a "fuzzy" optical versus "known" wired issue. but i could be wrong...

for a wired sync connection, it is very easy to determine the trigger voltage and duration (buy an old nikonos or motormarine camera ad measure the pulse).

what to do with optical?

it appears you have good results wen your strobes are troggered via wired sync. seems to indicate that none of your strobes have an excellant optical sync system...

Giffenk,

thanks for your thoughts, but I do have problems with my YS110a AND both of my Z240 V.4 with optical triggering. So all three have a bad optical sync system? Hmmm.

The Olympus does not have an option for hard-wiring the strobes, so that is why i tried the external Heinrichs-Weikamp converter. If you do not know it: It is OPTICALLY triggered and sends the signals via cable to the electrical port of the strobes. Unfortunately, the old internal converter (that fits to the cameras hot shoe) does not work with the latest Oly cameras; I confirmed this with the heinrichs-Weikamp office; and they told me they would not produce an updated version.

Jock

Greetings

Joerg

Joerg: Your results are quite different from mine at least with respect to land using the small olympus strobes. I will check again tonight and post some pictures, but I have had reasonable results with Z240 at least as they seem to mimic the TTL of the camera itself. I will try also to put an oscilloscope on the signal and see what is up.

Bill

Thanks Bill,

I will leave for a non-diving vacation (shame on me...) on Friday, and right now I do not have enough time to post my test results for a comparison. But I will do so when I am back in three weeks.

Jock

I've never had problems with my EM5 and EM1 with S2000 or Z240 in sTTL. What shutter speed you using? If memory serves, the EM5 tops out at 1/250, EM1 can do 1/320. I've used Inon and Nauticam cables, no problems with either. You can try removing the fiberoptic cables and just pointing your main strobe directly at the optical sensor (or use their mirror adaptor if you have one) to rule out cable problems.