[Shakir] sent us this fairly easy way to do high speed photography. The idea is to use a microphone to detect a sharp sound on a surface and trigger the flash. The camera is set up with a long exposure to capture the action. Assuming your room is dark enough, you shouldn’t get much ghosting in your exposure. The circuit is a two stage amplifier that engages the flash using a silicon controlled rectifier. Be sure to check out the photos, some are pretty stunning.
long exposure? don’t you mean short exposure?
No, I think the idea is to keep the shutter open during a window that there should be something cool, but then have the flash go off when something cool happens. If tweaked right everything else will be underexposed, while the flash will provide the majority of the lighting.
This isn’t high-speed photography, but rather great timing photography, right?
It is using a camera at regular speed in a dark room (thus the shutter is open longer) with a flash that you trigger at just the right moment. Those two items combined = high speed photography
High speed photography has almost always been done with slow shutter speeds.
Before eletronic shutters at least, it was far easier to make a light flash for 1/100,000th of a second than to make a mechanical shutter operate that fast. Even with modern DSLRs, the fastest shutter speed is often maybe 1/4,000th of a second — far too long if you’re trying to capture a bullet in motion.
With electronic shutters, it’s probable possible to have incredibly fast shutter speeds, but then you need huge amounts of light — it’s still far easier to make a blinding flash of light than to make a continuously blinding light. :-)
this all still assumes that whatever is making the noise isn’t faster than the sound. For example, this couldn’t be used to take a photo of a bullet.
very true. trying to make a shutter open and close that fast is very difficult. the best way around the problem is using a flash of light. the idea was originally put forth by Harold Eugene “Doc” Edgerton. http://web.mit.edu/Edgerton/
ps: unfortunately, a lot of the images on my website are not loading due the enormous number of hits :]
apparently google sets a page view limit on websites it hosts :(
@ehrichweiss
not true. lets say i keep my mic 1 cm from my gun. we know sound travels at roughly 340 m/sec in air at 20 deg C. use speed=distance/time -> the sound takes roughly 30 u sec to reach the mic.
now, a bullet travelling at say 900 m/sec will have moved a mere 27 mm in that time. so you see, we have a huge margin to work with
That’s all well and good if you’ve got a cheap enough mic that you’re comfortable with aiming a gun 1cm away from it!
you are not going to shoot the microphone for heavens sake! just keep it near the gun. and how expensive are condenser mics? a few cents!?
Cool stuff. I’ll have to get someone to make this for me.
One thing, though. His flash duration looks too short. If you set a flash on full power, the duration of the flash can cause blurring. If you set it at a lower power (1/2, 1/4, etc.) the burst will be shorter, and the image sharper. Of course, you will have to increase the ISO/set a larger aperture…
Wow, that looks really cool. My kids would get a kick out of setting something like this up.