Techniques to capture high-speed sequences

[daved31415]

I have been reading about Doc Edgerton and Eadward Muybridge's pioneering in high speed photograph techniques. I started with the Wikipedia articles, moved on to "milk drop coronet" and surfed around from there.

I am wondering if there is a technique which would involve taking photographs of separate events. For instance, in the case of a sequence of photographs showing a fluid drop, if each photograph was taken of a different drop and then those photographs were used to create a sequence which shows what a drop looks like. What would that photographic technique be called?

Thanks.

 

[dennybeall]

If it's the same drop over time then it's Time-lapse. If you take multiple photos of the same event and overlay them it could be HDR or just a sequence. The movie folks would probably say slow-motion video. Not my thing, perhaps someone else has a better answer for you.

 

[Overread]

You can do this with a single exposure.

What you need is a shot where the exposure is majority or fully created by flash light. That is if it were taken without flash light the shot would be 100% dark (ergo underexposed). As a result the flash light is then contributing all of the active light for the shot.

Now a flash pulse has a period of time that it lasts for (very fast if using speedlite flash units). Thus all the motion stopping happens from the flash and that split-second pulse of light. However a singe full blast from a flash is a bit slower; fast enough to freeze action, but not fast enough to get more than one drop into a shot as the flash has to recharge before discharging again.

Thus what you do is use multiple flash units and one of two methods:

1) Highspeed sync" mode. This makes the flash pulse the light from it at a lower power rating. This is used for fill flash when using fast shutter speeds; however in this shot what it will do is capture a split-second part of the subject falling multiple times over in the same frame. Of course you might need more than one flash because the single flash has now lowered its power out-put.

2) Multiple flash units and a highspeed trigger (3rd party custom setup). This works on higher powers and simply sequences the flashes to fire one after the other in fast succession; bonus is you get more power per shot.


Note if any ambient light contributes to the shot you'll get a blur in the motion between each sharp frame. If you're ok with this and have the right ambient light you can do a series with a single flash in burst mode as outlined above - with the blur suggestion motion in the shot (though for a fast waterdrop it might not be fast enough to get many stages).

 

[Buckster]

I am wondering if there is a technique which would involve taking photographs of separate events. For instance, in the case of a sequence of photographs showing a fluid drop, if each photograph was taken of a different drop and then those photographs were used to create a sequence which shows what a drop looks like. What would that photographic technique be called?

It's called a composite. It's done by using a special computerized trigger that allows for minute microsecond adjustments to get each photo needed in the sequence, and then compositing the images together in post processing.

I've not put together a sequence like that, but just setting up the trigger means using different timings and getting the drops in different stages while dialing in on the one being sought for the final images.

There are several of these computerized triggers on the market. They control various aspects of the process, from when to fire strobes to when to cause pumps to squirt out a drip, to processing signals from a wide variety of sensors, and then allowing the user to use multiple different sources and outputs to control the thing as a whole. I myself use the Camera Axe system for those purposes.

 

[daved31415]

Thank you Buckster.

 

[creisinger]

@ daved31415:
I'm interested in what exactly you are trying to achieve but since English isn't my native language I have trouble understanding your goal.

1. Are you trying to capture one photo at the time a drop hits a liquid surface and you want to capture the corona effect as you have mentioned in your first post?
or
2. Are you trying to capture several photos that show the drop falling, hitting the surface and then creating the corona effect as an animated sequence? That would be considered slow motion right?