Author Topic: Fast flash photography  (Read 5880 times)

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Offline tpe

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Fast flash photography
« on: March 20, 2006, 01:10:54 PM »
I think someone has posted some fast action pictures here before but i cant seem to find them, anyway what i was wondering is if anyone has some hints? I tryed messing around with this type of thing before, but with the things available in the kitchen i couldnt make an invisible trigger or freeze the action enough so didnt go any further, http://thebort.net/tpe/tomatoes.jpg, but now i have one of these...

Sound Trigger-Delay Unit Package with Breadboard
Item Number:  SK2-DU-BB
http://www.hiviz.com/kits/sk2-du.htm

If anyone has tryed this or similar things before? what is a good (fast) flash to use and how fast is fast? the shots above were too slow and i was wondering what the best way of freezing the action is and of course any other advice, and just to see anyone else's work and hear how it went.

tim

Offline xeroid

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Re: Fast flash photography
« Reply #1 on: March 22, 2006, 02:50:09 AM »
Used to do it years ago with sound or light triggered flash units but had to be in a darkened room so flash was sole illumination otherwise ambient light gave blur. Flash fires at about 1/50,000 sec so it will stop motion the action but room needs to be almost black.

Your specific use/subject will determine how you can trigger the light source, I had a strobe for multishot on bulb, long since expired after trying to boost output too high with more capacitors.
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Offline tpe

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Re: Fast flash photography
« Reply #2 on: March 22, 2006, 08:38:41 AM »
Sorry to hear the strobe died, i was thinking of trying to get one to wor too. In the shots i have tryed with my macro ring flash the subject has still been blurred (see the example in the link above), i have a metz, that i will probably have to bounce to get the light levels down enough but i would have thought it would take even longer than the ring? Is there a measurement of how long a flash takes to fire? so if i do get another one i know what to look for? Or what to look for in a strobe.

Also any sugestions for subject matter that hasnt been done to death before? shooting tomatoes and eggs gets a bit messy and there are loads of pics on the net. I was thinking of trying to get some kind of smoke system going so as the shock waves of the impact may be visable, but difficult as like you say the whole thing has to be blacked out (which i did in a packing case) so the smoke tends to get in the way of the lense.

tim

Offline sprint16v

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Re: Fast flash photography
« Reply #3 on: January 04, 2007, 03:58:36 PM »
did you have any success with the sound trigger?
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Offline tpe

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Re: Fast flash photography
« Reply #4 on: February 21, 2007, 10:01:24 PM »
Sorry just seen this, err not a lot, the flash wasnt fast enough to catch the action, the sound trigger worked perfectly, but shooting the fruit/veg/eggs just made it into blurrs and streaks. i'll see if i can find some pics in the morning.

tim

Offline sprint16v

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Re: Fast flash photography
« Reply #5 on: February 22, 2007, 07:15:31 PM »
odd the flash didn't stop the action. is it the ONLY light source?
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Offline tpe

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Re: Fast flash photography
« Reply #6 on: February 22, 2007, 09:00:43 PM »
Yeah, but i think it is just too fast for a normal flash, if you happen ot know anything about strobes it would probably be usefull.

Sorry this was the only one i could find, the rest are archived...



The fash really ends up looking slow, the pellet hit at about 900 fps, i guess thats jut too much :(

tim

Offline ecniv

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Re: Fast flash photography
« Reply #7 on: February 22, 2007, 10:47:25 PM »
Are you using the built in flash or a gun - though the gun would allow speeds up to 4000?

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Offline tpe

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Re: Fast flash photography
« Reply #8 on: February 23, 2007, 07:21:56 AM »
It was an off camera flash, but i think a slow one, and i guess it was about that, the pellet would travel about 7 cm in the time the flash takes to go off if it is 1/4000 second, so that one of the bits of egg has traveled 1 cm or so is not too unreasonable i guess.

tim

Offline xeroid

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Re: Fast flash photography
« Reply #9 on: February 26, 2007, 08:47:15 AM »
Hmm. some discrepancies here.
The '4000' is the fastest 'shutter' time that the flash can work with.
But Flash actually fires at up to 1/50,000th of a second so should stop the action pretty much. I think earlier Flashes were slower because of tube persistence ie the after glow of the ionised gas inside but even so they were in the 1/10,000th of a  second region.
Strobe is exactly the same except it can repetitive fire albeit at a lower light level.
My early experiments with this were with open shutter ( film days ), totally blackened room and strobe rates of about 2 - 10 per second or sound triggered single shots. Wasted a lot of film and time .....b&w and a ready darkroom required,.. and a patient wife.
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Offline sprint16v

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Re: Fast flash photography
« Reply #10 on: February 26, 2007, 02:49:36 PM »
like xeroid says something odd going on, what happens if you take a pic along the barrel (looking away of course :-) ) when the flash triggers can you see the pellet or do you get a line?
Alternatively maybe the flash is fireing twice in quick succession.
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Offline tpe

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Re: Fast flash photography
« Reply #11 on: February 26, 2007, 10:48:55 PM »
I cant really say what else it could be, perhaps the times quoted for a flash (the types i tryed are cheapoish on camera, a sigma, a ring and a 2800 minolta) are how long it takes to fire, but that it takes a while for to fire up and down for an entire cycle?

I got a couple of pictures with the pellets visable as a streak about 5 cm long, unfortunatly they are all on a dvd somewhere in a big pile with no indexing except date, here is another one that made me put it on the back burner, although i would very much like to start again if i can get my hands on a faster flash...

http://www.scientificillustration.net/_temp/carrot.jpg

and the original as my host died for that one that was one of the better ones but on old fashioned film, you can see the pellets in the middle and left picture...

http://www.scientificillustration.net/_temp/tomatoes.jpg

But i must say i have never looked down the barrel and really don't reccomend it :).

tim


Offline sprint16v

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Re: Fast flash photography
« Reply #12 on: March 15, 2007, 01:13:48 PM »
what shutter speed did the camera use?
  an experiment, in a dark room with shutter speed set to say 20 secs and  a pendulum in shot.

What sort of result would you get triggered manually it should be nice and sharp,  worked with mine with an ancient flash held off to the side. Got one image for each flash.How many different flash units have you got to  try out?
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