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The world's bulkiest TTL optical trigger....


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#1 rtrski

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Posted 23 May 2016 - 02:59 AM

So, home-made solution to an antique problem, although variations might be useful in some cases still....

 

I am shooting with a rather old Sony A55 SLT, from the very first generation 'translucent' mirrored series that is currently capped by the A99 full frame (which I use above water).  The SLT series has electronic viewfinders.  I have an Ike housing but elected to use Inon Z240 strobes vs. Ike 125/160/161 for their smaller size.

 

Unfortunately, in these very first SLTs, the A33 and A55, Sony 'helpfully' had the viewfinder mimic predicted exposure results to give the photographer a "what you see is what you get" type intuition.  Unfortunately, in an underwater housing with manual strobe sync, that means it 'helpfully' turns black with settings like ISO200, f11, 1/160th underwater because the camera doesn't know you're getting significant light boost from a strobe.  AF module works fine - but you're shooting blind.  Using the EVF tunnel or the rear screen makes no difference.  UW photogs are a tiny market but this same effect hampered studio photogs with radio triggered flash, so for the next generation SLTs (starting with the A65) Sony offered a 'setting effect off' option in the menu so the EVF brightness is always tied more to ambient light not exposure prediction.  (Same option is available in all the A6xxx and A7 mirrorless offerings now).  Will help me when I upgrade but for now....

 

The only other fix is TTL - as long as the camera knows a strobe is indeed present, f11, 1/160th or so isn't going to black out the viewfinder.  I do have a DS51 which I use when shooting macro (and have a fiberoptic half-ring flash arrangement I printed up posted about elsewhere).  Finally getting a dive trip again this year to a location I want to shoot wide angle with the Inons again, so decided to do something about my dilemma.

 

Hence - a cover plate to use the DS51 as the light source for optical sync to the Inon z240 sensors, but without having the light from the DS51 influencing the shot by just letting it blap out all over.  Printed a cover and 'adaptors' for the sensor caps on the Inon to accept any TOSlink audio S/PDIF cable.  At like $6-8 from Monoprice vs. the much more expensive underwater manufacturer fiber optic cables, I can afford to keep a few spares around expecting the inevitable corrosion around the FO tips (since these were clearly never intended for saltwater immersion).  Cable in the picture is a Monster TOSlink cable I had laying around and look forward to drowning (purchased many moons ago before I knew what a**hats they were as a company....)

 

First pic of connection (two FO links available at the strobe face, only one currently in use) below.

Attached Images

  • DSC08994.jpg

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...


#2 troporobo

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Posted 23 May 2016 - 04:10 AM

I love your solution - excellent work even if unwieldy.   As a DIYer myself (tube powered analog audio) I admire the spirit and share your antipathy to Noel Lee's company



#3 giffenk

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Posted 23 May 2016 - 11:35 AM

Awesome. You obviously have way too much spare time on your hands.
Have you thought about mounting issues? I recently added a repurposed ttl controller and struggled with mounting options. I tried a larger tray and arm system but eventually went back to my original smaller tray.

#4 rtrski

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Posted 23 May 2016 - 01:38 PM

I've got some 3-way ball clamps.  Was going to mount the DS51 to one handle right above the housing with that, then route the FO cables up the arms to each Inon.  There's also the top ball mount on the housing itself but I don't feel comfortable using that for a DS51.

 

Will put up some pics of the full rig once I get a configuration I think I like.

 

Yes, it'll be some extra bulk (and likely make the whole assy more negative, since I also use a mini-dome with the 8-16 mm lens) but the last time shot wide angle (3 years ago...sheesh) the black EVF just made for way too much frustration.  Missed focus because I was just pointing and hoping on things like this:

 

https://flic.kr/p/bs4ywH

 

And the time's worth it if it helps me eke out another trip without regretting not upgrading, or restricting myself to macro only....


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...


#5 rtrski

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Posted 28 May 2016 - 10:28 AM

OK, some better photos of the full set up as I intend to dive with it (need to add a couple more cable straps here and there along the arms, or just go with handy-dandy 'lectrical tape.  Oh, and a dome might be a good plan.

 

Assisted by my o-ring destructive seal tester (aka Shedomatic Generator Mark IV)....

 

Sorry for the multimeter behind it in the views - kind of looks like it's part of things and makes it seem more complicated than it really is.  Like the internets, this whole thing is just a series of (light) tubes....

DSC08996.jpg

 

DSC08998.jpg

 

DSC08999.jpg

 


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...


#6 JohnVila

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Posted 08 June 2017 - 08:12 PM

 

 

Assisted by my o-ring destructive seal tester (aka Shedomatic Generator Mark IV)....

Ha - loved it - we have 2 "Shedaomatics" - thank goodness for magnifying glasses and vacuum seals!! A sure fire way to make sure your orings are very carefully inspected!



#7 drywh

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Posted 19 January 2018 - 06:33 AM

My DIY dome,I can not show my pic, why?