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Optical versus electrical strobe sync


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#1 CeeDave

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Posted 14 August 2008 - 06:07 AM

All,

I have searched this site, googled and clicked away, and still can't find a good discussion of the factors to consider in choosing optical versus electrical strobe connections. I care about this because, first, I am considering moving to Inons (for weight, compactness, and AA); and, second, because I had a minor leak in a sync bulkhead (Subal/Nikonos) and it got my attention (hooray for leak detectors -- no damage after a thorough cleaning and drying!). I'd be especially interested in discussion for Subal/Nikon, as that's my setup: I have seen the external Inon converter -- what are its advantages over electric sync? Any chance of more streamlined, leak-resistant converters for Subal (e.g., something that fits on the hot shoe or in the housing)? I prefer not to Do It Myself -- I'm a modeler, not an experimentalist!

Plus, I hate those fiddly Nikonos plugs...

My thanks for any links or discussion here.

Regards!
Chris White
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#2 rtrski

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Posted 17 August 2008 - 06:40 AM

I can't believe no one has responded to this yet. I was watching from the sidelines, not being an 'eddicated' person on this subject, but guess I'll try to help you get something started.

My guesses as to pro/con:

Optical:

Pro: no 'floodable' connection, can disconnect and reconnect in water if necessary, independent connections to each strobe (e.g. no T-type sync cable) eliminates single-point failure, no camera hotshoe required, FO cable cheaper than electrical sync (???)

Con: right now, I believe, no generally-supported UW TTL protocol for optical triggering. Craig has posted that the protocols exist however I don't know of anyone implementing them right now. May trigger with surrounding flashes (other photogs, etc.). Requires internal strobe firing with possible impacts to battery life, fogging in housing, and mitigation for backscatter from the internal strobe.

Electrical:

Pro: cable acts as secondary attachment if strobe mount fails*, TTL supported, many TTL conversions available for just about any camera/housing/strobe combination support. Does not fire camera's internal strobe. Very reliable firing with almost zero likelihood of misfire due to other photographers, strobing line beacons, etc.

Con: cable costly and can be damaged. Damage to T-cable can take out both strobes at once. Extra bulkhead penetration required on housing and strobes. TTL solutions are proprietary and 'lock you in' to certain manufacturer/combination once purchased vs. being agnostic. TTL circuitry may be incorporated in housing and flood if camera does. Requires camera with hotshoe to utilize.

*Regarding the "pro" listed of secondary attachment, which I bet got a few eyerolls on first reading, I use two old DS50s that the prior owner must've "stripped" the plastic around the little screw that holds in the blade-like mount attachment (going to either the Ikelite round flat 'washer' adapter or a ball-type adapter). On BOTH of them, on my first dive trip, the screws fell out (never saw them again) and the strobe heads just 'slid' off the blades, dangling by the cables, scaring the (bleep!) out of me. Fortunately the cables prevented the heads from plummeting into the depths. Doubt a skinny little FO thread would've done that. :chatterbox: Since then I just wrapped some teflon tape around the blades to get a tighter fit and didn't bother trying to replace the screws.

Current rig: Sony SLT-alpha55 in Ikelite housing, Sigma 105mm f2.8 DC Macro w/ Ike 5505.58 flat port or Sigma 8-16mm f/4.5-5.6 DC HSM behind UWCamStuff custom 5" mini-dome. Dual INON z240 Type IVs triggered with DS51 for TTL mimicry, or DS51 alone with home-made ringflash assy for macro.

 

Topside, unhoused: Sony SLT-alpha99, Sigma 150-500mm + 1.4TC (Saving for Sony 70-400 G2), Sigma 15mm diagonal fish, Sony 24-70mm f2.8 CZ, Tamron 180mm f2.8 Macro...all the gear and nary a clue...


#3 craig

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Posted 17 August 2008 - 07:20 AM

As Alex said in another thread, fiber is more a focus of the Japanese makers. If there were more universal demand, that could change but right now fiber's disadvantage is no universal adoption.

My experience is that sync cords are the most prone to failure of all parts in a rig. That alone many not be such a problem, but when a sync cord fails it can cause all sorts of unpredictable behavior since it's electrically connected to the camera. Most "ghosts in the machine" find their way in through a sync cord IMO. That's why I want to eliminate them.

With Subal, there's a number of ways to take advantage of fiber but they will all use at least one bulkhead. One way is to use the Inon adapter. I have no experience with that part but it's what I'd try if I were pursuing a Subal setup now. The Inon part will not get you TTL nor is it compatible with wired TTL converter. A second way is to use one conventional wired strobe and drive others off of it using fiber. The wired strobe could support iTTL. You could use a housed SB800 for example or an iTTL converter with a wired Inon strobe.

Ryan at Reef Photo has experience with Subal, TTL converters, and all those little details. He also sells the Inon converter. He may be a good source of practical experience on that part.

Heinrichs has just introduced a CLS receiver for selected strobes. In an email I received last night, he said that they've been available in quantity for a couple of weeks now. This device will convert a number of different strobes, Inon Z240 included, to a Nikon CLS slave! This converter does not have a fiber connection and Heinrichs isn't sure it needs one. One could be added with a little ingenuity. The obvious method to use this is with a wired SB800. I would also like to see a manufacturer house the Nikon remote commander (SU800). I will be trying this receiver with a Seatool D300 housing. With the Seatool, the popup flash can function as the CLS commander. :chatterbox:
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#4 ornate_wrasse

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Posted 17 August 2008 - 08:33 AM

With Subal, there's a number of ways to take advantage of fiber but they will all use at least one bulkhead.


I just got back from Cozumel where I used fiber optic on one strobe. It turns out that I only had one insulation plate. Steve Philbrook, the Inon rep, was there diving with us and set up my rig to use fiber optic for one of my Inon strobes. The strobe was set up as a slave to fire when the strobe that was electrically connected went off. The disadvantage was that my buddy noticed my strobe firing in response to his strobe and he had to move far enough away from me that it wouldn't be a problem.

Ellen
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#5 ce4jesus

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Posted 17 August 2008 - 09:00 AM

I guess this is more of a question than an answer but if you have an Inon converter connected wouldn't you be able to use the strobes built-in ttl? I've found Inon's wireless s-ttl superb and as good as my camera on land. Finally, if you simply run a fiber optic cable from your hardwired strobe to the Inon slave you can eliminate other cameras triggering the strobe.
Gary
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#6 craig

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Posted 17 August 2008 - 04:03 PM

I guess this is more of a question than an answer but if you have an Inon converter connected wouldn't you be able to use the strobes built-in ttl? I've found Inon's wireless s-ttl superb and as good as my camera on land. Finally, if you simply run a fiber optic cable from your hardwired strobe to the Inon slave you can eliminate other cameras triggering the strobe.

No, sadly not. I've never gotten an explanation and never asked, but the Inon converter does not support the iTTL protocol and does not work when connected to a Sea & Sea TTL converter. It only works on manual. I think adding iTTL to the Inon converter would be great, but basically that's a Nikon SB400 in a nicer package. Nexus has shown a prototype housing for the SB400.
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#7 Edward Lai

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Posted 24 August 2008 - 08:01 AM

No, sadly not. I've never gotten an explanation and never asked, but the Inon converter does not support the iTTL protocol and does not work when connected to a Sea & Sea TTL converter. It only works on manual. I think adding iTTL to the Inon converter would be great, but basically that's a Nikon SB400 in a nicer package. Nexus has shown a prototype housing for the SB400.


Hey All,

The trend is that more Nikon flashes will be used underwater in near future, triggered by the in-camera flash acting as CLS commander. Many new housings coming out for D200, D300 and soon the D90 and D700 will have optical connectors before the pop-up in-camera flash unit.

One advantage of optical connection is that divers can use different connectors at either end of the optical fibre, regardless of brand or standard, and still get the flash signals through.

I had visited the Japan Dive Festival this April and found Zillion makes very good Nikon flash housings for SB-800 and even SB-R200 (for macro photography). Subal, Fantasea and Jonah also make housings for SB-800. There will probably be more Nikon flash housings to come especially for the new SB-900.

I just tried my Nexus D300 housing using 2 SB-R200 in Zillion housings, and connected with 2 Inon optical fibres and the system works well, giving me the full advantages of the Nikon iTTL functions. Most importantly I don't have to worry about exposure setting when I switch ISO and aperture.

The transition to full optical connection for Nikon iTTL systems is still at its early stage as different manufacturer have different connectors, and some housings even don't provide any solution for optical connection. But as it advantages become more known by divers I think the time will come.

Edward

#8 bruceterrill

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Posted 24 August 2008 - 08:25 AM

Hey All,

The trend is that more Nikon flashes will be used underwater in near future, triggered by the in-camera flash acting as CLS commander. Many new housings coming out for D200, D300 and soon the D90 and D700 will have optical connectors before the pop-up in-camera flash unit.

One advantage of optical connection is that divers can use different connectors at either end of the optical fibre, regardless of brand or standard, and still get the flash signals through.

I had visited the Japan Dive Festival this April and found Zillion makes very good Nikon flash housings for SB-800 and even SB-R200 (for macro photography). Subal, Fantasea and Jonah also make housings for SB-800. There will probably be more Nikon flash housings to come especially for the new SB-900.

I just tried my Nexus D300 housing using 2 SB-R200 in Zillion housings, and connected with 2 Inon optical fibres and the system works well, giving me the full advantages of the Nikon iTTL functions. Most importantly I don't have to worry about exposure setting when I switch ISO and aperture.

The transition to full optical connection for Nikon iTTL systems is still at its early stage as different manufacturer have different connectors, and some housings even don't provide any solution for optical connection. But as it advantages become more known by divers I think the time will come.

Edward


Hi Edward,

Do you have a link to the Zillion housings for the SB-R200 housings? I have tried looking at the Zillion web-site before but it seems to be lacking in detail.
If you have a link or could supply me with some info on the little housings, I would be truly grateful...
Thanks for taking the time mate,

Bruce...

#9 craig

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Posted 24 August 2008 - 10:24 AM

I am also interested in the Zillion SB-R200 housing. If they are small enough they would be really interesting for macro.

I think using the popup flash as a CLS commander is a good feature for the housing makers provided there are compelling CLS strobes to use. It would also be great to have a housing for the SU800 for everyone else. The SU800 would have the advantage of 3 remote groups instead of two.

I wish Inon would add native CLS to their strobes, particularly the upcoming S-2000.
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#10 tdpriest

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Posted 15 September 2008 - 01:41 AM

using the popup flash as a CLS commander is a good feature


Surely you would get the same problem as you do with the internal TTL function on the Inon z240 (which I find highly effective, by the way)? If the camera's pop-up fires when the Inon is turned off there is a lot of internal reflection from the dome port, which contaminates the image.

Tim
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#11 Gudge

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Posted 15 September 2008 - 01:50 AM

Surely you would get the same problem as you do with the internal TTL function on the Inon z240 (which I find highly effective, by the way)? If the camera's pop-up fires when the Inon is turned off there is a lot of internal reflection from the dome port, which contaminates the image.


I just converted my Subal 40D housing to fibre optic sync cords. Part of the kit was a foam ring that fits around the lens next to the camera and blocks any light getting into the port:

Posted Image

I've had no problems with internal reflections inside the dome port with the external strobes either on or off.
Canon 7D, Nauticam NA-7D housing, 2 x Inon Z240, 1 x Inon S2000, Tokina 10-17 & 12-24, Sigma 17-70 Macro, Tokina 35 macro, Canon 60 & 100 macro, Tamron 2X & Kenko 1.X Teleconverters.

#12 craig

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Posted 15 September 2008 - 09:36 AM

Surely you would get the same problem as you do with the internal TTL function on the Inon z240 (which I find highly effective, by the way)? If the camera's pop-up fires when the Inon is turned off there is a lot of internal reflection from the dome port, which contaminates the image.

Tim
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In CLS mode, you can set the popup flash to contribute nothing to the exposure. The flash still fires to trigger the other strobes and it is visible rather than infrared like the SU800.

My guess is that there would still be the potential for internal reflections but turning off the Inon strobes would not result in increased strobe output from the popup.
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#13 E_viking

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Posted 15 September 2008 - 12:42 PM

Well, just my couple of thoughts on the matter.

My wife seems to have more problems with her fiber optical cables, breaking not firing etc etc

I am more nervous of water leakage with my TTL cables.

/Erik

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#14 ChasO2

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Posted 24 September 2008 - 04:31 PM

My wife seems to have more problems with her fiber optical cables, breaking not firing etc etc

/Erik


Maybe try one of the Audio optical fibres for a more robust optical connection, see: http://wetpixel.com/...showtopic=23789