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Microflash to fire optical strobes without using camera's flash


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#21 Jesper64

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Posted 08 September 2011 - 01:24 AM

I think it will fit/screw in any nikonos bulkhead (just like any nikonos cord will fit in any nikonos bulkhead) with a double waterproof seal (the nikonos typical seal plus one more o-ring on the top). As for the length, I will have to measure it but you can get an idea from the third picture, around 3mm or so (equal or less than the electronic cables)...


Makes sense that it would be a standard Nikonos sync cord screw thread.

Looking at the Hugyfot housing the Nikonos bulkhead appears to be much taller than the one on my Sea & Sea housing. That's why I'm querying about the length from the top o-ring to the end of it. I suspect it may protrude out a bit more than in a Sea&Sea housing than on the Hugyfot.

Thanks

Edited by Jesper64, 08 September 2011 - 03:57 AM.


#22 bvanant

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Posted 11 September 2011 - 03:34 PM

You actually don't need much of a circuit. Get a CR2032 battery holder and a superbright Red LED from Radio Shack. I put two batteries in the holder to get 6 V to over drive the LED. The hardest part is getting a good hot shoe connection, I disassembled an old strobe that had stopped working and just used the connector part. Wire the batteries through the hot shoe to the LED and you are good to go. The other tricky part is optically coupling the LED on the inside of the housing to the fiber optic bulkhead. Placement needs to be just right at least on my Nauticam. With an S2000 or Z240 at low power you can fire the camera as fast as it will go.

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#23 blueglass

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Posted 12 September 2011 - 04:03 AM

You actually don't need much of a circuit. Get a CR2032 battery holder and a superbright Red LED from Radio Shack. I put two batteries in the holder to get 6 V to over drive the LED. The hardest part is getting a good hot shoe connection, I disassembled an old strobe that had stopped working and just used the connector part. Wire the batteries through the hot shoe to the LED and you are good to go. The other tricky part is optically coupling the LED on the inside of the housing to the fiber optic bulkhead. Placement needs to be just right at least on my Nauticam. With an S2000 or Z240 at low power you can fire the camera as fast as it will go.

Bill


Trying directly connection of a LED (in series with the battery) with a D7000, the LED stayed on continuosly after the first shot, it didn't work for me.
I have came back from my trip and the little device has worked perfectly in thousands of photos. It works with my own custom made fiber optic cables and connectors and Inon strobes. It won't work with stock Nauticam cables or other brands than don't let so much light to go through. Most probably it won't work with Sea&Sea strobes which have less sentitive light sensors.
You should respect the cooling instructions of the strobe manufacturer after several shots, otherwise you may burn the strobes.
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#24 rtrski

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Posted 12 September 2011 - 05:57 AM

Trying directly connection of a LED (in series with the battery) with a D7000, the LED stayed on continuosly after the first shot, it didn't work for me.
I have came back from my trip and the little device has worked perfectly in thousands of photos. It works with my own custom made fiber optic cables and connectors and Inon strobes. It won't work with stock Nauticam cables or other brands than don't let so much light to go through. Most probably it won't work with Sea&Sea strobes which have less sentitive light sensors.
You should respect the cooling instructions of the strobe manufacturer after several shots, otherwise you may burn the strobes.


Might need a current-limiting resistor. Bill's LED might have one integrated, and yours might not have. I'm starting to seriously consider this route myself. Maybe buy a hotshoe 'extension cable' to get the shoe hardware for the contact points.

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...


#25 bvanant

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Posted 12 September 2011 - 06:19 PM

Might need a current-limiting resistor. Bill's LED might have one integrated, and yours might not have. I'm starting to seriously consider this route myself. Maybe buy a hotshoe 'extension cable' to get the shoe hardware for the contact points.

One thing that is still puzzling to me is that if I hook up throgh the hotshoe, then it works fine. If I hook up through the PC connector then the LED comes on and stays on even if the PC cable is plugged into the hotshoe connector. I was under the erroneous assumption that both the hot shoe and the PC connector did the same thing but clearly not. I used very large LEDs rated for a 2.3 V and drive them at 6 more or less. They will fire through the standard INON optical cables; I haven't tried to see if they are capable of triggering the S&S strobe

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#26 rtrski

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Posted 12 September 2011 - 07:22 PM

Measure the resistance with an ohmmeter between the GND contact and the 'flash activation' contact on both the PC connector and then on the hotshoe. Bet there's a higher resistance between the two on the hotshoe, so that's acting like your current-limiting resistor, while the PC sync contact resistance isn't. Either that or the PC sync 'hot' pin (Flash activation) is higher voltage (??)

I'm still slowly learning this stuff. It's embarrassing, I'm an electromagnetics designer (microwave and RF plumbing, antennas, arrays). But basic active circuits give me fits; I can't even spell tramsister (but I think I dated one, once. She was kinda mannish....)

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...


#27 bvanant

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Posted 14 September 2011 - 06:42 PM

Measure the resistance with an ohmmeter between the GND contact and the 'flash activation' contact on both the PC connector and then on the hotshoe. Bet there's a higher resistance between the two on the hotshoe, so that's acting like your current-limiting resistor, while the PC sync contact resistance isn't. Either that or the PC sync 'hot' pin (Flash activation) is higher voltage (??)

I'm still slowly learning this stuff. It's embarrassing, I'm an electromagnetics designer (microwave and RF plumbing, antennas, arrays). But basic active circuits give me fits; I can't even spell tramsister (but I think I dated one, once. She was kinda mannish....)

If you think it's tough for an RF engineer, its a lot worse for a country chemist.

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#28 cor

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Posted 14 September 2011 - 11:25 PM

One problem with using the hotshoe itself to connect the led is that you cant control how long the led stays on very well. It might be better to use the hotshoe to detect release, and then use your own electronics to fire a led, with your own timings.
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#29 bvanant

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Posted 16 September 2011 - 06:19 PM

One problem with using the hotshoe itself to connect the led is that you cant control how long the led stays on very well. It might be better to use the hotshoe to detect release, and then use your own electronics to fire a led, with your own timings.

Probably true if you want fancy output, but I just wanted to trigger the external strobe at any sync speed. The hotshoe LED appears to stay on for about 1.5 to 2 msec and that is enough to trigger my Inon strobes. S&S will be tested tomorrow.
If you can build your own electronics to get longer or shorter strobe pulses (in TTL mode) then I think you are way ahead of the game, unfortunately I am not that smart about electronic stuff.

Bill

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#30 rtrski

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Posted 17 September 2011 - 08:16 AM

Well, I found a hotshoe adaptor for about $8 (being on Sony, the rail is that iISO jobbie) that looks like it screws apart. That should give me the contacts to the hotshoe, as well as perhaps at least the bottom half of any enclosure. Just have to wait on the shipping from HongKong now. Will let me test out circuit board layouts and etching with pool acid and hydrogen peroxide... (no, not kidding...and a laser printer lets you do the 'masking' for the etch).

Think I might try a "real" LED circuit, designed to protect the LEDs from burnout, but of course probably ends up costing about $10 in parts vs. a quarter of that. Basing it on a small controller from Zetex (ZXSC310). Won't give me TTL timings by any means, but with SMT components I should be able to keep it's circuitboard size around .5 x 1.5" (including a coin battery holder).

My wife thinks I'm crazy. "Can you imagine what airport security is going to do to your camera bag when they see a little bitty battery-operated homemade circuit board with an LED on it attached to a so-called "camera"????" Hmmm...and I was going to build a SmartTrig intervalometer too....

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...


#31 rtrski

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Posted 03 October 2011 - 07:56 AM

Blueglass, mind sharing your circuit? I can't seem to get mine to fire off. I ditched the Zetex controller concept and went with just 2 BJTs in a Darlington amplifier configuration, with the LED as the load and resistor to protect the NPN's from too much input current.

The current gain is enough that the LED is on the bare edge of lighting with the input to the base of the first transistor 'open' (you can get it to almost flicker on with just tickling the LED with your finger on the breadboard)...if I short across the two pins to the hotshoe with just my finger, it lights up nice and bright from just the leakage current my skin can carry. But when I fire the shutter to see if the actual hotshoe analog pulse lights up the LED, it barely flickers. I suspect I need some cap for storage or something....?

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...


#32 rtrski

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Posted 10 October 2011 - 06:18 AM

Wow, I'm talking to myself now. ^_^ Finally got it working, pic in breadboard form confirms LED is triggering on when the shutter is open. (This shot was 1/100th, it also worked at 1/160th but was darker so I just uploaded the slower test shot).

Posted Image
Breadboard_10msec by rtrski, on Flickr

Turns out what I was doing wrong was trying BJTs. They just didn't react fast enough no matter what I tried. Switched to a FET circuit and voila, first try.

I've got the circuit board etched (about 1.4 x 1.3", including room for the coin battery holder, a trimmer to adjust brightness a little, and a full 'off' switch just to make sure there's no battery drain in case the FET isn't truly "off"). Will get mounted up onto the hotshoe adaptor and confirm fit inside the Ike housing sometime this week, then (strobes arrive Monday nite) will start playing around with a FO attach point to the Ike top DLSR ball mount. (Preferrably while keeping the ball for a focus light).

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...


#33 Dupsbear

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Posted 15 October 2011 - 07:21 AM

Wow, I'm talking to myself now. ^_^ Finally got it working, pic in breadboard form confirms LED is triggering on when the shutter is open. (This shot was 1/100th, it also worked at 1/160th but was darker so I just uploaded the slower test shot).

Turns out what I was doing wrong was trying BJTs. They just didn't react fast enough no matter what I tried. Switched to a FET circuit and voila, first try.

I've got the circuit board etched (about 1.4 x 1.3", including room for the coin battery holder, a trimmer to adjust brightness a little, and a full 'off' switch just to make sure there's no battery drain in case the FET isn't truly "off"). Will get mounted up onto the hotshoe adaptor and confirm fit inside the Ike housing sometime this week, then (strobes arrive Monday nite) will start playing around with a FO attach point to the Ike top DLSR ball mount. (Preferrably while keeping the ball for a focus light).


Congratulations RTRSKI! I know we will all be interested in seeing what you finally come up with and hopefully you will share your circuit.

BTW- I tried a TIL906-1 high output infrared LED, available from Radio Shack, to trigger my SB800 Nikon and Sea and Sea YS90 TTL Duo strobes. By shorting the LED leads with a 2032 coin cell battery, the infrared LEDs fired both strobes much more reliably than high power red LEDs. Using IR LEDs might also keep one from photographing the IR flash reflection on the inside of a clear housing or port; this idea needs some investigation since many cameras are super sensitive to IR.

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#34 rtrski

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Posted 15 October 2011 - 04:19 PM

I tried your trick of an LED in line with the hotshoe mount and a battery, and the Sony doesn't fire the LED. If the LED/battery/hotshoe-signals-to-ground loop is current protected, I can understand why. I've got to have a FET to respond to the trigger signal (current thru the hotshoe shorted triggering signal is very small, which is just enough to activate FET making drain->source go to short, then higher current flows thru that and LED). As for my circuit, I actully stole it from someone else here in another thread, there seem to be about 3-4 in various places about this subject:

http://wetpixel.com/...t...st&p=278235

Got a few more shots up. Circuit now integrated into hotshoe and fits into housing. Didn't even have to put PVC or electrical tape over the 'rivets' on the inner face that hold the Ikelite top clamp on as nothing hits it that would risk a short. Just linking to the pics in a set on Flickr instead of embedding them all in this post, if you don't mind peeking. Never mind the scary bald man in the background of the triggering test.

http://www.flickr.co...6388071/detail/

Had to drop to 2016 vs. 2032 batteries to use a shorter holder. That might be a problem in the long run as 2016's don't have the same current capacity. Still, the circuit works although the LED isn't as bright, and I was able to re-confirm it fires in the frame and will trigger a z240 held up to the outer wall of the housing (no fiber yet). It won't trigger the z240 if I hold it about 2-3 inches away, but the LED I have has only a 20degree lens arc and I don't know what the photodetector's arc is, so its hard to line it up perfectly by hand. More than likely if it triggers thru the wall with no light waveguide (fiber), there's enough light to trigger with a waveguide assuming I can get one rigged with the right orientation. I do have some flexibility still for moving around the LED in the trigger circuit, and/or adding a reflector behind it to help gather the light further.

I'm using a white LED, but the IR LED is interesting...wonder if it would work with the z240 photodetectors as well. Might give it a try. But if I have problems it'll probably be that I just don't have the gain I needed with the 2016 batteries and need to re-think an integration that lets me go back to the 2032's.

So the next step is coming up with a good fiberoptic link. I've got a small sample of (of all things) a near black Corian (the counterstop stuff...basically solid acrylic) which I thought I'd mill to get it to fit over the top ball mount on the housing and still let the ball fixture mount on top of it. The LED is placed sort of between the housing clamp handle and the top mount, so using that is perfect to hold the housing end of a FO link. Of course I'm too cheap to just buy a prebuilt FO cable, even though someone linked (on another thread?) a nice cheap Epoque one that has a stick-on housing end. Although I may find I regret it, I was going to drill the 'cap' for the photodetector that came with the z240 to mount some 3mm endglow fiber with a little ring of heat shrink tubing on the inside to captivate it, then use the piece of Corian to capture the 'input' end. Not sure if "ll need lenses or reflectors of some sort to help with the light coupling into the fiber....guess that's the next magic trick to figure out.

Edited by rtrski, 15 October 2011 - 04:22 PM.

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...


#35 Jesper64

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Posted 20 October 2011 - 04:01 AM

Looks very neat rtrski, nice work.

#36 escape

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Posted 20 October 2011 - 04:02 AM

[vimeohd]30847452[/vimeohd]

It's work! I use two cr2032 to get 6v and two LED for trigger.
Thanks rtrski!

#37 rtrski

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Posted 20 October 2011 - 05:06 AM

It's work! I use two cr2032 to get 6v and two LED for trigger.
Thanks rtrski!

Glad I could help, but we all need to be thanking "uwdiy". I stole the circuit from him (I know you used it too, but just pointing it out for other readers since we discussed that in a PM). Link is in my last post.

One quick comment: the circuit "uwdiy" put up shows the 2 LEDs in parallel. I've read that this is a bad arrangment, if the two LEDs aren't exactly alike (which they can vary a little) the one with the higher resistance gets less current and is dimmer, while the other gets more so it gets brighter and hotter. As the circuit would work with just one LED you're probably ok (even if all the current shunted to the one, you'd not have any more than if there were only one) but for equal brightness I've read you should put the LEDs in series. That makes sure they get equal current, and since each one has a relatively small resistance with 6V they should still both light just fine.

I hope this weekend to build my F.O. holder for the Ike top ball mount location, and my own fiber cable. That may prove almost more challenging than getting the circuit compressed to fit the housing, as I'm going to have to clean up the garage and bust out the router to mill some acrylic. So far everything else has been done with an Exacto knife, sandpaper (to score / snap / clean edge on circuit board), a laser printer and basic household chemicals for etching, a soldering iron, and a hot glue gun to goo the board down onto the hotshoe mount. Not so impressive when I outline it that way, is it? ;)

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...


#38 escape

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Posted 20 October 2011 - 05:54 PM

I tried put two leds in series but it was not bright enough triggering strobes via optical cable so change to parallel.
Now it's successfully trigger S&S ys-27dx, ys-02 and Inon z240 & s2000 but not ys-110a.
I think sensor on ys-110a is less sensitive then others.

P.S
Just ordered IR led for testing. I'll report soon. ;)

#39 owfotograaf

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Posted 20 October 2011 - 10:51 PM

Working also on a microflash. Here some conclusions:

- IR leds consume to much energy for the amount of light they give
- use red leds with a wavelength as high as possible
- you can overdrive many leds, 100mA during 100ms is no problem, see specs, so 2ms is no problem!
- CR cells do not give enough current :guiness: , if you want to use the ratings above and use more than one led
- the hugyfot fiber adapters reduce the distance with half :guiness:, trigger distance without is now approx. 30cm

And now, gone do some more tests! ;)

#40 rtrski

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Posted 21 October 2011 - 05:22 AM

Well, I got the strobe end (z240) of my fiber optic cable working. Just drilled a small hole in the captive 'plug' end to the screw-on photodetector cover that came with the strobe and used a good plastic bond glue to glue in a thick lightpipe fiber (3mm "endglow" fiber optic), then wetsanded the inner face with 600grit to get a nice clear smooth cut end. Holding the other end (just snipped, not buffed or anything yet) of the fiber to the LED trigger for a test (no plastic housing between yet either) I could get it to fire the strobe just fine even with a 10' (~3meter) length of fiber. Of course I'm using z240 type 4's which have the more sensitive detector, and 3mm is pretty darn big fiber optic diameter. But I'm very hopeful that this weekend's experiment to come up with the fiber mount for the Ike housing end will not have to be quite as precise as I was expecting, especially once I drop my fiber length to 1 meter or so. Nor (so far) does it seem I'll have to go back to CR2032's from the CR2016's.

escape: You're probably fine leaving the LED's in parallel if they are indeed from the same package and exact same type.

owfotograf: Are you saying your LED's currently trigger your strobes from 30cm with no fibers? (Just thru air??) If so, wow! Mine won't trigger the strobe from further away than about 2" (about 5cm), even with the strobe photodetector really well aligned with the LED's 20degree lens cone. But I am using two CR2016's so I am for sure current-limited. Right now I'm using white LED's but I'm considering switching to an amber that I found the specs for which should be about 2x the brightness (almost 20mcd). The one I have now is your typical domed-plastic white LED rated at 10mcd but the luminous flux is still fairly low.

Edited by rtrski, 21 October 2011 - 05:26 AM.

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...