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High Speed Photography

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Alessandro

Mon Feb 13 2006, 08:35AM

Registered Member #70 Joined: Thu Feb 09 2006, 08:19AM
Location:
Posts: 43

Hello everyone,
I know some other members have done some high speed photography and I thought I'd like to attempt it too, here are my results so far.

The two pieces of Aluminum foil act as a trigger for an external flash unit. I set the camera's shutter to a long exposure time, dim the lights, use a torch to focus the camera then depress the shutter button and fire. The projectile strikes the trigger and a picture is taken. Any help, hints, tips, suggestions and your own results welcome.

Bjørn

Mon Feb 13 2006, 09:17AM

Registered Member #27 Joined: Fri Feb 03 2006, 02:20AM
Location: Hyperborea
Posts: 2058

If the flash has adjustable power then the lowest power level will give the shortest exposure time. It will also help to tidy up the background so the picture becomes less cluttered. If the camera looks down slightly on the target then the picture often becomes more interesting.

Dr. Shark

Mon Feb 13 2006, 09:28AM

Registered Member #75 Joined: Thu Feb 09 2006, 09:30AM
Location: Montana, USA
Posts: 711

A normal flash unit will not be capable of very short exposured, since it is driven by electrolytic caps at a low voltage which take a milisecond or so to discharge. You can actually see some blurring on your photo. If you are serious about this, you should try constructing a high voltage flash unit which can discharge in microseconds. You will need a pulse cap and a high voltage trigger mechanism for this.

I like the way you use the Al foil to trigger the flash, I have to try this too! Did you just connect the wires from the foil to the flash units contacts, or is this a more complicated hack?

HV Enthusiast

Mon Feb 13 2006, 12:42PM

Registered Member #15 Joined: Thu Feb 02 2006, 01:11PM
Location:
Posts: 3068

The VIVITAR 285HV flash units are a popular high speed flash unit which can be moidified. I used a series of (3) of them to shoot water drops and with modification, the flash duration was reduced to 250us. You could probably get even faster with these as well.

Dan

Alessandro

Tue Feb 14 2006, 06:42AM

Registered Member #70 Joined: Thu Feb 09 2006, 08:19AM
Location:
Posts: 43

Thanks for the input everyone,

joe doh wrote ...

I like the way you use the Al foil to trigger the flash, I have to try this too! Did you just connect the wires from the foil to the flash units contacts, or is this a more complicated hack?

Yep, I just connected the two pieces of Al foil to the trigger plug that connects to the camera. I'm going to build an audio trigger over the weekend when I have some free time.

The flash unit I have is a Vivitar 1900, does anyone know about the suitability of this one? I might replace the flash capacitor with one of a smaller value to obtain a shorter flash.

Penguin7471

Tue Feb 14 2006, 09:42AM

Registered Member #71 Joined: Thu Feb 09 2006, 08:23AM
Location:
Posts: 63

Hi,

I was into high speed photography for a bit, even set up a special place where i dropped the stuff, or did whatever ... broken glass is something u dont want everywhere.

Anyway the setup is in a small room with lights off. A sound triggered flash unit which i made (out of a usual disposable flash unit with 1uf cap instead of usual 100uf and some random sound triggering circuit) is triggered via a microphone placed near the source of the bang, or kaboom or whatever.

The camera exposure is as long as i need to press the buttons.. etc. Typically 3 seconds will do. As you can see, it was a bad idea to use white cardboard for a background.

Photos below fairly self explanatory...for the whole lot of them (probably like 35 of them) go to my msn spaces thingy..

and "high speed photography" section.

HV Enthusiast

Tue Feb 14 2006, 12:40PM

Registered Member #15 Joined: Thu Feb 02 2006, 01:11PM
Location:
Posts: 3068

Another cool thing you can do is use several IR beams to set up at a specific point (within a dark box for example) which is connected to your flash trigger. Put some sort of flying insect in there, and when it crosses all beams at once (specified point), have the flash go off and get some cool photos of insects flying.

Tesladownunder

Tue Feb 14 2006, 04:25PM

Registered Member #10 Joined: Thu Feb 02 2006, 09:45AM
Location: Bunbury, Australia
Posts: 1424

Sounds like fun. If I get my cap bank and discharge a few kJ into a CD to generate an intense aluminium flash in about 30uS I might be able to light up a plane or two as they go overhead. (for the setup see post 63 here)

Peter

Part Scavenger

Tue Feb 14 2006, 05:15PM

Registered Member #79 Joined: Thu Feb 09 2006, 11:35AM
Location: Arkansas
Posts: 673

This is awesome! I got interested in this last week when I got a new Nuts and Volts that showcased a trigger mechanism. Haven't had any time to do anything. Anybody want to see the schematic?

Grant

Tue Feb 14 2006, 06:14PM

Registered Member #7 Joined: Thu Feb 02 2006, 04:32AM
Location: Central Florida
Posts: 18

I would like to see the schematic from that article.
Nuts and Volts has the PCB for it here.

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