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High speed flash sync.
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Harold Gough



Joined: 09 Mar 2008
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Location: Reading, Berkshire, England

PostPosted: Fri Mar 14, 2008 6:38 am    Post subject: Reply with quote

DaveW wrote:


By the way Danny have you tried to photo a bullet coming towards the camera and stop it with flash, and if you do try where do we sent the flowers too? Twisted Evil

DaveW


Dave,

How could you? Violence towards lenses and cameras is not be be encouraged! Shocked

Harold
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cannyman



Joined: 05 Mar 2008
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PostPosted: Fri Mar 14, 2008 1:45 pm    Post subject: Reply with quote

DaveW wrote:
I have Stephen Dalton's "Borne on the Wind" which is similar Danny. Many people do not realise when set up close to the subject and on manual low power just how short the flash duration that forms the image using a camera type flash gun can be, high speed sync shutter speeds can not approach this.

I did read but can't locate the article again that camera type flash guns are best for this type of photography, as though it is termed power settings on them it is a bit of a misnomer as the flash intensity is not reduced on "lower power" settings only it's duration as the flash is simply quenched quicker, hence the lowest power setting has the shortest flash duration for stopping action.

However it claimed studio flash works differently in that power settings on that mean the flash duration stays the same but their power (light output) is reduced. Therefore for stop action high speed flash a camera type flash gun on low power setting is preferable to studio flash because the flash duration will be a lot shorter. How true this is I do not know?

By the way Danny have you tried to photo a bullet coming towards the camera and stop it with flash, and if you do try where do we sent the flowers too? Twisted Evil

DaveW
Catching a bullet with HS flash is a bit tricky. As it is the b of the bang that triggers the flash . To have a setting of the flash to catch a bullet in flight would require a flash of such duration it would not have left the barrel. A precision delay would be required. I`m to tired to calculate the delay.
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Danny
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PostPosted: Fri Mar 14, 2008 2:15 pm    Post subject: Reply with quote

Quote:
By the way Danny have you tried to photo a bullet coming towards the camera and stop it with flash, and if you do try where do we sent the flowers too?


I actually tired that Dave, now I can only see out of the left eye Wink
yeah, that one Wink No wonder I can't focus properly any more, I'm cock eyed.

I actually tried 2ms, 5,ms,10ms,15ms an 20ms. So somewhere in between there, would be the bullet. If you could spend the time and tried a few dozen eggs, you would get it for sure Wink Jan wouldn't give me any more eggs Cool Rolling Eyes



Home made unit that one. My brothers an electronics technician.

That egg shot there and going through my notes was actually at 1/64,000th of a sec. Not 1/32,000th. Yes as we set the shorter durations, the distance must decrease. Fast duration = less power and thats where Stephen Dalton comes into it. Very clever guy and I'm glad you have that book. Its one I must get. Time to check out Amazon. Wink

Even though the flash duration is a lot faster than the shutter when set to std sync, the problem comes in when the auto sync kicks in. That now tries to control the flash duration and we then have no control over that high speed. Also which can be a benefit, is cameras that can switch to rear curtain sync. The advantage with that if we have it, is that it can show a trail behind the subject in motion. Certain subjects only though. With the mechanical complications of shutters/curtains, we are far better off to be in complete control of the flash duration. Like most photography IMO, the camera is just a dumb box.

All the best and interesting subject.

Danny.
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rjlittlefield
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Joined: 01 Aug 2006
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PostPosted: Fri Mar 14, 2008 2:39 pm    Post subject: Reply with quote

cannyman wrote:
Catching a bullet with HS flash is a bit tricky. As it is the b of the bang that triggers the flash . To have a setting of the flash to catch a bullet in flight would require a flash of such duration it would not have left the barrel. A precision delay would be required. I`m to tired to calculate the delay.

Hhmm... Muzzle velocity is on the order of 1000 feet per second -- one foot per millisecond. Trigger delay for electronic flash should be miniscule in comparison. 1/64,000 second will still blur pretty bad, though.

Triggering by sound with a supersonic round should be easy -- place the sensor close to both the camera and the bullet path so it can listen to the shock wave as the bullet goes by, then adjust the delay by tweaking the microphone position. For subsonic rounds, you can still set delay by positioning, though it gets trickier. Or trigger with a laser beam to be interrupted by the bullet, oriented so the camera can't see the beam.

--Rik
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augusthouse



Joined: 16 Sep 2006
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Location: New South Wales Australia

PostPosted: Fri Mar 14, 2008 3:07 pm    Post subject: Reply with quote

Stephen Dalton has another book (1 of many) titled:

"Split Second - The World of High Speed Photography"

ISBN: 0881620637 (Soft Cover)




Craig
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Danny
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PostPosted: Fri Mar 14, 2008 3:10 pm    Post subject: Reply with quote

Aww Craig, that ones a must have by the looks. Thanks for helping me spend more money Very Happy Have not heard of that one and going to check it out now thanks.

Danny.
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DaveW



Joined: 04 Aug 2006
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PostPosted: Sat Mar 15, 2008 2:11 am    Post subject: Reply with quote

Apparently Stephen Dalton has written 15 books if you want the set Danny!

http://www.stephendalton.co.uk/info.html

http://audubonmagazine.org/dalton.html

I think he did join Oxford Scientific Films at one time before it was bought out and Peter Parks and others moved on to found another firm.

I found these on flash triggers etc whilst searching for Dalton:-

http://courses.ncssm.edu/hsi/pacsci/fpaper.html

http://www.hiviz.com/activities/guidebook/hsptutor.pdf

http://schutt.net/john/photo/education/flash/2006-8_creative_flash_handout.pdf

http://findarticles.com/p/articles/mi_m1306/is_n11_v58/ai_12978213

For Nikon owners who make their own triggers there are the wiring details of the 10 pin plug on this link:-

http://www.outdoorphoto.co.za/forum/archive/index.php/t-2029.html

DaveW
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cannyman



Joined: 05 Mar 2008
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Location: UK

PostPosted: Sat Mar 15, 2008 2:28 am    Post subject: Reply with quote

nzmacro wrote:
Quote:
By the way Danny have you tried to photo a bullet coming towards the camera and stop it with flash, and if you do try where do we sent the flowers too?


I actually tired that Dave, now I can only see out of the left eye Wink
yeah, that one Wink No wonder I can't focus properly any more, I'm cock eyed.

I actually tried 2ms, 5,ms,10ms,15ms an 20ms. So somewhere in between there, would be the bullet. If you could spend the time and tried a few dozen eggs, you would get it for sure Wink Jan wouldn't give me any more eggs Cool Rolling Eyes



Home made unit that one. My brothers an electronics technician.

That egg shot there and going through my notes was actually at 1/64,000th of a sec. Not 1/32,000th. Yes as we set the shorter durations, the distance must decrease. Fast duration = less power and thats where Stephen Dalton comes into it. Very clever guy and I'm glad you have that book. Its one I must get. Time to check out Amazon. Wink

Even though the flash duration is a lot faster than the shutter when set to std sync, the problem comes in when the auto sync kicks in. That now tries to control the flash duration and we then have no control over that high speed. Also which can be a benefit, is cameras that can switch to rear curtain sync. The advantage with that if we have it, is that it can show a trail behind the subject in motion. Certain subjects only though. With the mechanical complications of shutters/curtains, we are far better off to be in complete control of the flash duration. Like most photography IMO, the camera is just a dumb box.

All the best and interesting subject.

Danny.
SSNAP. Even the cases are the same Surprised


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Danny
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PostPosted: Sat Mar 15, 2008 3:01 am    Post subject: Reply with quote

Very Happy Very Happy Snap alright Wink Great to see, I thought I was the only nutter on here Cool

That sensor on top of the sound trigger, what is that ??? Photo electric cell or something else ?? Excellent to see, love it Wink

I've been going through Amazon there Dave and some of his books you can get second hand for $1.00 - $5,00 US. Caught in motion cost me half a weeks wages at the time and well worth it.

All the best and great setup there.

Thanks as well Dave.

Danny..
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cannyman



Joined: 05 Mar 2008
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PostPosted: Sat Mar 15, 2008 3:10 am    Post subject: Reply with quote

nzmacro wrote:
Very Happy Very Happy Snap alright Wink Great to see, I thought I was the only nutter on here Cool

That sensor on top of the sound trigger, what is that ??? Photo electric cell or something else ?? Excellent to see, love it Wink

I've been going through Amazon there Dave and some of his books you can get second hand for $1.00 - $5,00 US. Caught in motion cost me half a weeks wages at the time and well worth it.

All the best and great setup there.

Thanks as well Dave.

Danny..
That thing on top was a slave sensor, but I needed the hotshoe part for mounting a small flash instead of the Sunpak. I enclose another gizmo I thought up. It`s to fire the Sunpak on the second flash of an onboard camera flash I have made several versions of it, mainly for pluggibg into the back of a studio flash.
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Danny
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PostPosted: Sat Mar 15, 2008 3:19 am    Post subject: Reply with quote

Is that for digital cameras that don't have a switch for the first burst. I had one camera that would only fire on the second burst, but the Sunpak kept up with it when set to around 1/32,000th sec. In other words, the Sunpak fired twice to keep up with the double burst of the camera. I've now got a flash with a built in slave that fixed that and it learns when the main burst is fired, whether its 1st, 2nd or even after a pulse.

Interesting and well done that man Wink

Danny.
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DaveW



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PostPosted: Sat Mar 15, 2008 3:42 am    Post subject: Reply with quote

No idea, I am not an electronics bod like you lot. I only found them searching for information on Stephen Dalton and passed the links on in case they were of interest. Here is another:-

http://hiviz.com/

DaveW
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cannyman



Joined: 05 Mar 2008
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PostPosted: Sat Mar 15, 2008 3:59 am    Post subject: Reply with quote

nzmacro wrote:
Is that for digital cameras that don't have a switch for the first burst. I had one camera that would only fire on the second burst, but the Sunpak kept up with it when set to around 1/32,000th sec. In other words, the Sunpak fired twice to keep up with the double burst of the camera. I've now got a flash with a built in slave that fixed that and it learns when the main burst is fired, whether its 1st, 2nd or even after a pulse.

Interesting and well done that man Wink

Danny.
Yes digital cameras do fire multiple flash`s. Some are ok on manual but not Canon. But thats no prob as you can use the FEL. It was OK until I purchased a Casio compact. The bleeder fires 3 flash`s, so it was back to the drawing board. But it was soon sorted. I made a de luxe model that counts the flash`s and shows them on an indicator. I will try and find a pic of same and post it.
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cannyman



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PostPosted: Sat Mar 15, 2008 4:08 am    Post subject: Reply with quote

cannyman wrote:
nzmacro wrote:
Is that for digital cameras that don't have a switch for the first burst. I had one camera that would only fire on the second burst, but the Sunpak kept up with it when set to around 1/32,000th sec. In other words, the Sunpak fired twice to keep up with the double burst of the camera. I've now got a flash with a built in slave that fixed that and it learns when the main burst is fired, whether its 1st, 2nd or even after a pulse.

Interesting and well done that man Wink

Danny.
Yes digital cameras do fire multiple flash`s. Some are ok on manual but not Canon. But thats no prob as you can use the FEL. It was OK until I purchased a Casio compact. The bleeder fires 3 flash`s, so it was back to the drawing board. But it was soon sorted. I made a de luxe model that counts the flash`s and shows them on an indicator. I will try and find a pic of same and post it.
Here it is, its a bit bigger, but it`s a mains version


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Danny
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PostPosted: Sat Mar 15, 2008 4:14 am    Post subject: Reply with quote

Now thats clever Very Happy Wink So it counts the number it flashes, very clever idea.

Danny.
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