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Two Sci-Fi Strobes.

Underwater Strobes Strobes

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#1 Kraken de Mabini

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Posted 24 May 2019 - 03:20 PM

Two Sci-Fi Strobes.

 

While collecting information on our beloved and often frustrating underwater strobes (1), I came across two ‘back from the future’ strobes which may be of interest to Wetpixel members, one maybe for underwater use, the other to photograph a bullet as it shoots out of your favorite gun. They seem to be of interest as they may portend the kind of underwater strobes in our future.

 

First, here is the just released Vela Strobe, compact, elegantly designed, with four AA batteries to power it for all day use.

Vela Strobe.jpg  

I quote its description (2):

 “The Vela One is the fastest flash you can buy. Take pin-sharp photos of supersonic bullets and explosions using a normal SLR.  The pulse width is adjustable between 500ns (1/2,000,000 sec) and 5µs (1/200,000 sec), which is fast enough to freeze a high velocity rifle bullet in flight. It can flash continuously at up to 50fps, and burst at up to 100kHz. This extremely short pulse means it needs to be orders of magnitude brighter than other LED flashes to achieve a usable exposure. The Vela One boasts nine ultra-bright 5000 lm chip-on-board LEDs, which are boosted over 2000%, giving peak flux of up to 1 million lumens.” (Please see Footnote 1)

The second strobe exists only as a two year old patent application (3) designed, maybe for deep diving submersibles, to work underwater at depths of 1,000 meters (3,281 feet) and to emit up to 30,000 lumens using a compact panel of 108 LED chips, in a hand-held light and photographic flash. The interesting idea is the use of a microprocessor to set and maintain a constant voltage to fire the LEDs (Footnote 2).. 

 

Comment:

Given the Vela’s small size, low power consumption and ultra-fast flashes, let us hope it soon re-incarnates as an all-solid state underwater photo strobe. 

Notably, these two strobes of the future are built around, not flash tubes, but high lumen LED’s (4).

--

Footnote 1:

The Vela brochure is instructive on how to design a high performance strobe:

 

“THE VELA SOLUTION: A MILLION LUMENS

For pin-sharp shots you need a much faster flash, and the Vela One is 100 times faster. With a flash speed starting at 1/2,000,000 second, or 500 nanoseconds, the Vela One will stop a supersonic, high velocity rifle bullet in its tracks.

We've all seen the beautiful high speed shots of bullets passing through playing cards and apples. If you want to take these sort of photos today, you will either need a high speed camera costing tens of thousands of dollars, or a dangerous and expensive air gap flash. These use a high voltage spark to generate the short, bright flash needed. As they run at over 25,000 volts and need regular and dangerous electrode replacement, it's not surprising you can't buy them commercially. If you want one you either need to buy a vintage one for thousands of dollars, or you must build one yourself. Many super talented people have done this, but it's not an option for most of us. We wanted to solve this.

 

To solve the problem we turned to LEDs. Until now this has been impossible, as high speed flashes need to be extremely bright in order to get enough light onto your sensor in such a short period. We worked out we'd need to aim for up to one million lumens. If we used regular ultra-bright (500lm) LEDs we would need around 2000 to achieve this. This is obviously far too expensive and impractical. Instead we turned to the latest "chip-on-board" LEDs. These are designed for applications such as exterior lighting of large buildings. Even at ten times the brightness of the regular LEDs we'd need 200 of them, which is still far too expensive and impractical. This is where we had to get clever. After months of experimenting with different circuits and LEDs, we have built a circuit that drives nine LEDs up to 20 times brighter than rated, without damaging them or overheating, pumping out up to one million lumens. We've flashed our test units hundreds of thousands of times, and they power on through. That's years of normal use, and far longer than a speedlight will last. (2)

 

Footnote 2: This strobe is designed for a depth of 1,000 meters and does not seem to fulfill a real time need, but who am I to say.

 

References:

1. Underwater Strobe Finder – 2019 edition. http://wetpixel.com/...showtopic=64076

 

2. Vela One high speed photo flash.   https://shop.vela.io..._eid=072409961b

 

3. Feiberg, Dirk and Frey, Charles L.: High Intensity Marine LED Strobe And Torch Light.  United States Patent Application 20170343185

http://www.freepaten...20170343185.pdf

 

4. Inexpensive high power, white light, 5700K COB (circuit on a board) LED’s:  https://www.mouser.c...ree led&FS=True


Edited by Kraken de Mabini, 24 May 2019 - 07:15 PM.


#2 bvanant

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Posted 25 May 2019 - 10:01 PM

The Vela is a cool idea, but it really doesn't put out a lot of light. The air GN is about 1.7 (compared to 32 for a YSD2.) This means that you will need to be a few inches from your subject. BUT it might be interesting to take their power circuit and put Z330 for example. The Chip on board LEDs are very interesting but ridiculously expensive compared to a flash tube. If you take 6 of them to get really high power you have about $400 just in LED parts (in 10,000 quantity).

Bill


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#3 Kraken de Mabini

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Posted 27 May 2019 - 08:49 AM

Maybe Bill is referring to a years old LED strobe, I forget its name, which was expensive and dim.  Now LED prices have tumbled and LED light output has increased dramatically.  On eBay powerful COB LED's are under $1 to $2.  Cree manufactures and Mouser Electronics (and others) sells a wide array of powerful COB LED's for under $10, even the most powerful.

The venerable Edison light bulb has joined the dinosaurs, replaced by a wide array powerful, low priced COB LED lights. "Let there be light " has become "Let there be LED light".

 

It is not surprising that over one billion cell phones use LED flashes for their inbuilt cameras, and that Vela chose powerful LED microsecond flashes to image speeding bullets. If one multiplies the photon output of a microsecond flash to that of a millisecond flash, the photon output increases by a factor of some 1,000.  This is why all new underwater lights are based on COB LED lights, they are blindingly bright.  

 

The white LED is not a gimmick, it is a fundamental change in the way we create light, as the  Nobel Prize committee recognized when it rewarded its inventors with the 2014 Nobel Prize in Physics. 

The presentation speech to Isamu Akasaki, Hiroshi Amano and Shuji Nakamura reads: 

 

"Thanks to the blue light emitting diode, it became possible to produce white lamps. Today these are everywhere – in our mobile telephones, our bicycles, our cars, our cities and our homes. By using an LED lamp for lighting instead of an incandescent light bulb or a fluorescent lamp, we save energy and thereby protect the environment. An LED lamp also has an incredibly long lifetime: approximately 100,000 hours, or about 11 years. Since it is so efficient, it can shine for many hours using the electricity from a battery, which can be charged using sunlight. LED lamps light up places on earth where there is no electrical power grid. They shine in the dark, when all other lights have gone out."

 

=

https://www.nobelprize.org/prizes/physics/2014/press-release/  



#4 ChrisRoss

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Posted 27 May 2019 - 10:13 PM

This is really not a breakthrough that extends beyond very high speed flash, they are over driving current LEDs to produce very bright light for very short periods,  they say themselves conventional LEDs are not up to the task, it's a niche application.  The issue will be that to get bright enough for UW work you need to increase duration of the flash and the implication I get is that this would destroy the LEDs they can stand the sort pulse but not the longer pulses required for conventional photography.  

 

To be correct they put out a lot of light but can only do it for very short pulses.  You have to be very close and also use wide apertures, most mobile phones are f2 or so, so they can get away with a lot less light compared to the f8 plus we want to shoot at underwater.



#5 Barmaglot

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Posted 27 May 2019 - 11:03 PM

The maximum pulse duration of this strobe is quoted at 5µs (five microseconds, or millionths of a second) - that's three orders of magnitude lower than the typical high-end underwater's strobes 3ms (three milliseconds, or thousandths of a second). In other words, while peak output is comparable to a xenon tube, the total energy delivered is somewhere between 300 and 1000 times less than, say, a Z-330. Since 5µs is quoted as a maximum number, I presume that overdriving those COB LEDs for a longer period will destroy them - might as well use the old-style flash bulbs. Like it or not, if you want to dump 50-250 joules into the water within the span of a photographic exposure, there is no real alternative to xenon tubes.



#6 hyp

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Posted 28 May 2019 - 03:56 AM

Give it 10-20 more years.



#7 bvanant

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Posted 01 June 2019 - 11:17 AM

I was referring to the currently available Subtronic Sirius. At 800 euros (about a grand) it is well built but still has a GN of only 8 (at ISO 200). Not terribly bright but fine for macro I think. 

In my mouser catalog, 3000 lumen COB LEDs are still about $30 each. You can get $5 COB leds but they are only 450 lumens. The problem I think is that we need like 40,000 lumens to make a good strobe flash. I know the lab at UCSB that did much of the Nobel work on blue LEDs. The guys there are not sanguine that you can make an alternative to a xenon tube any time soon. That being said, I have heard rumors of a new strobe coming out this fall that is supposed to be GN 32 (on land) and be LED based with 200 flashes from an 18650 battery. I don't believe it but we can hope.

Bill


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#8 Kraken de Mabini

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Posted 02 June 2019 - 09:07 AM

The best reply to clarify the above comments is to post the Vela narration of what they did to have a super bright, super fast LED strobe:

 

"High speed photography relies on a fast flash. Just like shutter speed with action photography, it's the duration of the flash that is important when capturing bullets and explosions. A typical speedlight has a duration of around 1/20,000 second (50 microseconds) on its fastest setting. This may sound fast, but a bullet will travel over 5cm or two inches in that time and will be so blurred it's almost invisible. Studio flashes are even slower. For pin-sharp shots you need a much faster flash, and the Vela One is 100 times faster. With a flash speed starting at 1/2,000,000 second, or 500 nanoseconds, the Vela One will stop a supersonic, high velocity rifle bullet in its tracks.

 

WHAT'S WRONG WITH HIGH-SPEED PHOTOGRAPHY

We've all seen the beautiful high speed shots of bullets passing through playing cards and apples. If you want to take these sort of photos today, you will either need a high speed camera costing tens of thousands of dollars, or a dangerous and expensive air gap flash. These use a high voltage spark to generate the short, bright flash needed. As they run at over 25,000 volts and need regular and dangerous electrode replacement, it's not surprising you can't buy them commercially. If you want one you either need to buy a vintage one for thousands of dollars, or you must build one yourself. Many super talented people have done this, but it's not an option for most of us. We wanted to solve this.

 

THE VELA SOLUTION: A MILLION LUMENS
To solve the problem we turned to LEDs. Until now this has been impossible, as high speed flashes need to be extremely bright in order to get enough light onto your sensor in such a short period. We worked out we'd need to aim for up to one million lumens. If we used regular ultra-bright (500lm) LEDs we would need around 2000 to achieve this. This is obviously far too expensive and impractical. Instead we turned to the latest "chip-on-board" LEDs. These are designed for for applications such as exterior lighting of large buildings. Even at ten times the brightness of the regular LEDs we'd need 200 of them, which is still far too expensive and impractical. This is where we had to get clever. After months of experimenting with different circuits and LEDs, we have built a circuit that drives nine LEDs up to 20 times brighter than rated, without damaging them or overheating, pumping out up to one million lumens. We've flashed our test units hundreds of thousands of times, and they power on through. That's years of normal use, and far longer than a speedlight will last."

-

Why LED's as the light source? Because they last many times longer than glass flash tubes.

Are they bright enough?  Yes, it is hard to argue with a light source of up to one million lumens.

Now let us hope that Vela, or some other enterprising folk, will replace our flaky underwater strobes with reliable smart strobes.

--

http://www.vela.io/v...igh-speed-flash


Edited by Kraken de Mabini, 02 June 2019 - 09:18 AM.


#9 Barmaglot

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Posted 02 June 2019 - 09:58 AM

Again, a 500ns flash is thoroughly useless outside the realm of high-speed photography (speeding bullets and the like). Underwater, we use the flash to overpower sunlight, and flash sync speeds for interchangeable lens cameras tend to range between 1/160s and 1/500s. Even at the top end of that scale (and very few ILCs reach it), 1/500s is two million nanoseconds. That is four thousand times slower than this LED flash longest pulse of 500ns. In practical terms, this means that the flash is active for only 1/4000 of the time that your shutter is open - the other 3999/4000 of the time, the sun is merrily filling your image with green and blue. If you use a fixed-lens camera with a leaf shutter capable of syncing at 1/2000s, you can reduce that to 1/1000... still nowhere near short enough for the flash to make a meaningful contribution to the exposure. Vela One's guide number is five feet in air - do you really think this is anywhere near ready to compete with Xenon tubes? And don't forget that it costs almost twice as much as a Z-330 or YS-D2.



#10 bvanant

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Posted 02 June 2019 - 10:27 AM

and it isn't waterproof. This is the problem with Lumens as a metric. Better we should talk about total energy per pulse or something like that.

Bill


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#11 Kraken de Mabini

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Posted 03 June 2019 - 06:49 AM

To expand on the above points:  The Vela is just an example of what can be done at microsecond speeds with new technology and LED lights, it was never meant to be used for standard nor underwater photography . My point is that, if modern LED lights can shoot at microsecond speeds, then they can be used in a properly designed strobe for underwater photography.  
 
Why take the trouble to do so? Because current glass strobe tubes are unreliable, and current popular underwater strobes even more so. All one has to do is read the many sad strobe experiences narrated in these pages, or as happened to me have two Inon Z240 strobes fail in the middle of a Raja Ampat trip. That is when I started to wish for a new and reliable light source for underwater photography. 


#12 Barmaglot

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Posted 03 June 2019 - 07:07 AM

 

My point is that, if modern LED lights can shoot at microsecond speeds, then they can be used in a properly designed strobe for underwater photography. 

 

 

No they can't. Vela One overdrives the LEDs far past their rated brightness for half a microsecond and no longer because pushing them any further would burn them out - and you'd need to push them several thousand times further in order to compete with a Xenon flash.

 

Put it this way: if you take a fairly typical 1/250s exposure, that's 4ms - 8000 times the length of Vela One's maximum of 500ns, during which it shines at 1 million lumen. One million lumen divided by eight thousand is 125 - i.e. it will take a 125lm LED to deliver a 1/250s exposure equivalent to Vela One's super-fast super-bright burst. You can get a 125lm LED that fits on a keychain for a couple bucks.


Edited by Barmaglot, 03 June 2019 - 07:13 AM.


#13 Kraken de Mabini

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Posted 03 June 2019 - 08:22 AM

At this time speculative arguments about acceptable strobe flash times are pointless, as the LED lights are becoming more powerful and of trivial cost, microprocessors are being used to control underwater strobes, ISO sensitivities are growing to be huge, to mention a few. 
The patent I quoted above (1) for a deep water LED lamp and photographic strobe addresses the voltage vs high speed issues and is interesting to read, a microprocessor is used to protect the unit from thermal overloads. The point is that as the patent's inventors have developed a photographic LED strobe that works at 1,000 meters deep, then one can be made for us to take pictures with at Scuba depth.
Another point is the ISO sensitivity of today's cameras is now so large that an ISO of 4,000 to 6,400 gives excellent photos (2), so that less current can be used to flash an LED. 
As all the basics are changing in our favor, I do hope the glass flash and its antique electronics are on the way out, they betray us much too often (3).
 
References
1.  Feiberg, Dirk and Frey, Charles L.: High Intensity Marine LED Strobe And Torch Light.  United States Patent Application 20170343185.  http://www.freepaten...20170343185.pdf
 
 

Edited by Kraken de Mabini, 03 June 2019 - 08:30 AM.


#14 Barmaglot

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Posted 03 June 2019 - 08:47 AM

 

At this time speculative arguments about acceptable strobe flash times are pointless, as the LED lights are becoming more powerful and of trivial cost, microprocessors are being used to control underwater strobes, ISO sensitivities are growing to be huge, to mention a few.

 

Nope, because the improvement that is needed for LEDs to become competitive isn't incremental - it's three orders of magnitude.

 

 

The point is that as the patent's inventors have developed a photographic LED strobe that works at 1,000 meters deep, then one can be made for us to take pictures with at Scuba depth.

 

Nope, because the challenges are fundamentally different. At 1km depth, you have zero sunlight. At scuba depth, you have plenty of sunlight ruining the colors in your shot.

 

 

Another point is the ISO sensitivity of today's cameras is now so large that an ISO of 4,000 to 6,400 gives excellent photos (2), so that less current can be used to flash an LED.

 

Again irrelevant, because as you bump up the ISO, you let in more blue/green sunlight, and need correspondingly more white strobe light to compensate - and if you don't close the aperture to something ridiculous, you'll just overexpose the shot.

 

The primary use of strobe lights in underwater photography is to expose the subject using white light delivered from close range, so as to avoid the blue/green tint caused by water absorbing the red/yellow part of the spectrum. This requires a substantial amount of energy (somewhere between 50 and 250 joules, depending on the strobe model) to be dumped into the water as light within, at most, a few milliseconds, so that the proportion of the light reaching the camera sensor is heavily skewed away from natural sunlight towards the strobe. There is no way to cheat this - if you want a colorful photo of a coral reef, you need lots of energy, delivered quickly. LEDs can deliver lots of energy slowly, or a little energy very very quickly - but not both, and the gap in capability isn't a matter of incremental improvement - it's a huge yawning chasm.

 

If you hate strobes so much, why don't you drop a thousand pounds on a Vela One, put it in a plexiglass box, take it down to a reef and see how it fares? Or, just shoot in ambient light - it'll be much cheaper and you won't need to put up with those nasty, evil, dangerous strobes.



#15 ChrisRoss

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Posted 03 June 2019 - 09:55 PM

The biggest problem we have is not that Xenon tubes is an inappropriate technology, it's that the strobes are built to a price point.  There was an earlier post where S&S stated they did not have the resouces to build a custom tube but rely upon off-the shelf items.  That appears to be changing with a few new models with circular tubes appearing on the market - but their price point is higher the Retra Pro is 50% more than an INON and the oneUW is nearly 3x the price.

 

I think it's probably unrealistic to expect otherwise at this stage.  The development costs need to be re-couped and if the number sold is not high - prices need to reflect that if we expect the vendor to stay around to provide support.  It remains to be seen if these new models live up to expectations.



#16 Barmaglot

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Posted 03 June 2019 - 10:16 PM

  That appears to be changing with a few new models with circular tubes appearing on the market - but their price point is higher the Retra Pro is 50% more than an INON and the oneUW is nearly 3x the price.

 

To be sure, the Retra Pro price ($961) is very close to that of Ikelite DS-161 ($999). Add a set of Eneloops to match Ikelite's included proprietary battery and they become identical, so $1k for a ~150J circular tube strobe isn't really new.



#17 ChrisRoss

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Posted 04 June 2019 - 05:58 AM

I mean higher compared to INON and Sea&Sea with the straight flash tubes....  I have not heard much about the oneUW strobes, no reviews I could find online............



#18 Barmaglot

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Posted 04 June 2019 - 07:44 AM

It's been that way for a long time now though, hasn't it? $300~450 for an entry-level strobe with a single straight tube (D-2000, S-2000, YS-01, YS-03, DS-51), $600~700 for a high-end strobe with straight tubes (Z-220, Z-240, Z-330, YS-D1, YS-D2), around $1k for some strobes (it's hard to call them low-end) with a circular tube (DS-160/161, YS-250), $2~3k for the high-end circular tube strobes (Seacam, Subtronic). I wonder, how much did Nikon's underwater strobes for film cameras cost when new?



#19 bvanant

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Posted 04 June 2019 - 08:08 AM

An SB 105 in 1996 was about $820 and an SB104 was $1560 which would be $1336 and $2542 in today's dollars. Data from a Nikon Dealer Price list and inflation data from US dept of commerce.

BVA


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#20 giffenk

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Posted 05 June 2019 - 02:00 PM

Fully functional SB105s can now be had for less than $100US.

Even worse confusion, S&S YS110 & YS110a which have a triple tube arrangement (which was ignored above?) are available used for around $250US ish.





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