Flash Expert pls help. Need powerful flash for project


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lowy

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Dec 24, 2005
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Hi all,
A noob here. Currently, I am doing a project on high speed photography. I need intense lighting to take picture at in terms of 0.1-0.2 million fps. Problem is that I am just those handheld flash like Metz 60 CT4 and Metz 30 BCT 4. I am unable to provide sufficient light to get enough details. I have tried placing my Metz 30 right in front of the target but it is still not enough. The thing is that because I am handling at very high speed, my target is in a small chamber, only Metz 30 can fit inside. Metz 60 is used to provide light from outside into the chamber itself from a tempered glass protection. From my vendor for the high speed camera, he recommend Bowen studio light flashes to be placed outside the chamber. I understand that flashes are graded by guide number but does the greater guide number meeans the light intensity is greater?
Just wondering if there is any other more powerful flashes or strobe lights. Also, can anyone of you recommend me the store to visit to know about them? I need to get quotations for those equipments so that my lab can buy them. BTW, I need to know where got sell flash bulbs and replace them for Metz flashes.

Thanks for your attention
 

Prismatic

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Feb 25, 2003
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#3
Hmm... are you sure you need 0.1 million fps? Or do you need a flash duration of 1/1000,000
sec? A 0.1 million fps is as good as a continuous light already, and any flash that can strobe at 0.1 million fps will probably fry after a few secs.
 

lsisaxon

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Nov 29, 2004
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#4
lowy said:
Hi all,
A noob here. Currently, I am doing a project on high speed photography. I need intense lighting to take picture at in terms of 0.1-0.2 million fps. Problem is that I am just those handheld flash like Metz 60 CT4 and Metz 30 BCT 4. I am unable to provide sufficient light to get enough details. I have tried placing my Metz 30 right in front of the target but it is still not enough. The thing is that because I am handling at very high speed, my target is in a small chamber, only Metz 30 can fit inside. Metz 60 is used to provide light from outside into the chamber itself from a tempered glass protection. From my vendor for the high speed camera, he recommend Bowen studio light flashes to be placed outside the chamber. I understand that flashes are graded by guide number but does the greater guide number meeans the light intensity is greater?
Just wondering if there is any other more powerful flashes or strobe lights. Also, can anyone of you recommend me the store to visit to know about them? I need to get quotations for those equipments so that my lab can buy them. BTW, I need to know where got sell flash bulbs and replace them for Metz flashes.

Thanks for your attention
What do you use for your high speed camera and for what duration do you need to capture for? What area do you need to illuminate?

Most of the time, for full flashes, the flash duration can be as low as 1/350s.
 

user12343

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May 15, 2005
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#5
dun really need expensive equipment to do the job. the important thing is WHEN and HOW you trigger the flash & exposure, be it sound-activated or light activated :) refer to here for details.
 

solarii

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Oct 20, 2005
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Wow... I think you should get stadium spotlights. Yes, those they fix at the national stadium. Bright, intense, and can stay on for days!

On a more serious note, guide number is used to calculate the range of the flash at a fixed ISO and given aperture. Can be used as a gauge of intensity/power, though that's not its intended purpose.
 

lowy

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Dec 24, 2005
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#7
To answer all of your questions. The camera can only take 18 images for every shot. And I can put the shutter opening up to 320us to 10ns, then the interval frame from 320us to 40ns. But the current lighting now only allows up to 5us for the images to appear ok. So I programmed the interval frame to be 40ns and shutter opening time to be 5us. So approximately 0.2 million fps. I am handling projectile travelling at speed from 100m/s to 600m/s.
As for the lighting, from my understanding my flash duration is too long approximately 5ms from the manual so it actually serves a continous light considering the little time the shutter open and close. I got no problem getting the delay timing for the triggering of the flash to the actual firing of the flash since I can place my flash in front of the camera and use the program to find out. For those interested, it is approximately 240us from the triggering of the Metz 60 CT 4 flash till the flash actually fired and appeared the brightest.
The main problem of my project is that the lighting is not bright enough. I suspect another reason is that the light intensity is greatly reduced since the light has to pass through the tempered glass for safety reason.
BTW, who knows where got sell flash bulb and help to replace them for Metz flashes?
 

sORe-EyEz

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Jun 28, 2005
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#9
try renting floodlamps instead? similiar 2 those Civil Defence use during Nicol Highway collapse? dunno where got such lobang... :sweat:
 

lsisaxon

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Nov 29, 2004
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#10
lowy said:
To answer all of your questions. The camera can only take 18 images for every shot. And I can put the shutter opening up to 320us to 10ns, then the interval frame from 320us to 40ns. But the current lighting now only allows up to 5us for the images to appear ok. So I programmed the interval frame to be 40ns and shutter opening time to be 5us. So approximately 0.2 million fps. I am handling projectile travelling at speed from 100m/s to 600m/s.
As for the lighting, from my understanding my flash duration is too long approximately 5ms from the manual so it actually serves a continous light considering the little time the shutter open and close. I got no problem getting the delay timing for the triggering of the flash to the actual firing of the flash since I can place my flash in front of the camera and use the program to find out. For those interested, it is approximately 240us from the triggering of the Metz 60 CT 4 flash till the flash actually fired and appeared the brightest.
The main problem of my project is that the lighting is not bright enough. I suspect another reason is that the light intensity is greatly reduced since the light has to pass through the tempered glass for safety reason.
BTW, who knows where got sell flash bulb and help to replace them for Metz flashes?
How big is your chamber and how big is the area of interest? What you can probably do is to use some lenses to focus the beam into the area of interest, and if that's not sufficient, link a few flashes to fire simultaneously. Or you can try those 1000Ws or 2000Ws studio flashes. They definitely have more power but you may need to redo your timings.
 

ellery

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#11
do a google search I came across an article on high speed flash photogrpahy where the author used the flashes from disposable camers - several of them to do the flashing. What 1 unit can not do for you several flash units might. Actually you need to fire as a strobe flash effect but since strobe is a fractional part of the full power you will need several flahses strobing to supply sufficient light intensity to give correct exposure.
 

Del_CtrlnoAlt

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Feb 15, 2003
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#12
sORe-EyEz said:
try renting floodlamps instead? similiar 2 those Civil Defence use during Nicol Highway collapse? dunno where got such lobang... :sweat:
actually, i think even continuous light may have problem for him... cos he shooting faster than the 1/60 speed... and flood light uses 230V or maybe other voltages, but its like 50hz or 60hz...

not sure about using a LED thou, might be able to use... does LED flicker? maybe 1 from the car xenon type may help too...
 

lsisaxon

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Nov 29, 2004
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A flash is sufficient since he has only 18 frames at one go. For an exposure of 5us and interval time of 40ns, the total exposure is merely 1/10000s. For most flash strobes, the duration is in the range of 1/500 to 1/20000. So to the high speed camera, even a flash strobe is almost like continuous light over the 18 frames. And each frame will only receive less than 1/18 the total power of the light in that burst.

One more question for lowy, what is the lens being used? I suppose the high speed camera uses Nikon F mount or C-mount?
 

lowy

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Dec 24, 2005
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#14
Yes. I am using a Nikon F mount. Aperature is 3.5. The focal length in use is about 100mm. The chamber is relatively cramped about 2 by 1 metre and I need to put in my target too. I actually dismantled my Metz 30 and extended just the flash bulb right behind my target to increase light intensity. Just want to ask how much does it cost to rent the studio lighting equipment for a day or 2? And where can I ask for it? No point asking my lab to buy if it does not work?
 

lsisaxon

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Nov 29, 2004
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lowy said:
Yes. I am using a Nikon F mount. Aperature is 3.5. The focal length in use is about 100mm. The chamber is relatively cramped about 2 by 1 metre and I need to put in my target too. I actually dismantled my Metz 30 and extended just the flash bulb right behind my target to increase light intensity. Just want to ask how much does it cost to rent the studio lighting equipment for a day or 2? And where can I ask for it? No point asking my lab to buy if it does not work?
It seems like you only need to illuminate the target? For a 100mm lens, the field of view should be rather narrow, I think you may benefit from using some lenses on your Metz 60 to concentrate the beam.
http://www.metz.de/en/photo_electronics/zubehoer.144-90.html
See Telephoto Attachment 60-42.
However, since the vendor has already recommended the Bowen studio strobe, then I think you can try going for that. I don't think a single strobe would cost more than $2k. With that, and if it's still not bright enough, you might want to modify it by mounting the flash tube in the chamber and running some highly insulated wires to the flash head. I don't think you can do that if you had rented a unit instead. Unfortunately, I don't know where I can rent these equipment also.

How much more light do you think you need? 1 stop? 2 stop? You may also benefit from a faster lens like the Nikon Micro 105/2.8. That would give you 1 more stop but will may reduce your depth of field (of sharpness).
 

sORe-EyEz

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Jun 28, 2005
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#16
Del_CtrlnoAlt said:
actually, i think even continuous light may have problem for him... cos he shooting faster than the 1/60 speed... and flood light uses 230V or maybe other voltages, but its like 50hz or 60hz...

not sure about using a LED thou, might be able to use... does LED flicker? maybe 1 from the car xenon type may help too...
dunno if LED flicker or not. some cars now use LED oso (older ver got slight blue tint). my EyEz cannot detect flicker oso arhz... :sweat:

i dun mind lend my LED flashlight 4 testing, i got 2 1 watt LED. ;p
 

lowy

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Dec 24, 2005
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#17
Whoa. 2K!!! Anyway, the High speed camera is originally for use on polariod with a phosphur screen. It is converted to digital mode by placing a ultracool digital camera taking a photo of the phosphur screen, something like photocopying. The lens setup for the digital camera is a large format lens (who knows what lens is this?) placed inverted directly to a 24mm, aperature f2.8 lens, which is connected normally to the digital camera. Anyone knows what this setup is? I believe that this setup is also responsible for the intense lighting required...
 

lsisaxon

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Nov 29, 2004
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#18
sORe-EyEz said:
dunno if LED flicker or not. some cars now use LED oso (older ver got slight blue tint). my EyEz cannot detect flicker oso arhz... :sweat:

i dun mind lend my LED flashlight 4 testing, i got 2 1 watt LED. ;p
Not enough power. Even laser diode also not enough power for a high speed camera setup.
 

lsisaxon

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Nov 29, 2004
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#19
lowy said:
Whoa. 2K!!! Anyway, the High speed camera is originally for use on polariod with a phosphur screen. It is converted to digital mode by placing a ultracool digital camera taking a photo of the phosphur screen, something like photocopying. The lens setup for the digital camera is a large format lens (who knows what lens is this?) placed inverted directly to a 24mm, aperature f2.8 lens, which is connected normally to the digital camera. Anyone knows what this setup is? I believe that this setup is also responsible for the intense lighting required...
Why should that be so? Modern high speed cameras can capture directly to harddisk. I don't know what kind of setup that is but it sounds quite old to me. How does it work? Does it just trace the movement of whatever you want to capture? In this case, the phosphur screen itself may not be able to give good resolution. Is there any direct electrical output from the high speed camera without going through the phosphur screen?
 

lowy

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Dec 24, 2005
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#20
Let's just say that the high speed camera I am using is at about 10 years old bah. I am not sure how it works or what you meant by tracing the movement?
That is another video based high speed camera which can capture in terms in seconds. The bad thing is that the higher fps it goes, the smaller the resolution it gets. For a 30000 fps, it can only provide 256 by 256 pixels...
 

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