Flash and Motion Blur

Using flash guns to capture the perfect water droplet photograph is one of the best ways to get the result you want. Flash provides plenty of light to use a small aperture giving a good depth of field and it reduces the effects of motion blur.

However it is very important to realise that it is the duration of the flash that freezes the image and removes the motion blur NOT the shutter speed, all of these images were taken with the camera in bulb mode and an exposure around 1/4 second. The amount of motion blur that is acceptable is down to the photographer but the higher the magnification being used the more motion blur becomes apparent.

This page attempts to illustrate the problem with motion blur and the ways to combat it.

The set up was a Canon 580Ex flash gun positioned 150mm away from the droplet which was in free fall approximately 200mm below the release solenoid valve. The timing to position the droplet was achieved using a Cognisys StopShot system . If you look at the position of the droplet against the ruler in each shot you will see it is gives a very accurate and repeatable droplet position, ideal for timing of water droplets.

Starting with the flashgun, in manual mode, on 1/1 (full power) each photograph ‘halves’ the flash power so the sequence is 1/1, 1/2, 1/4, 1/8, 1/16, 1/32, 1/64, 1/128 of full power. I have altered the aperture during the sequence in order to get a set of usable images.

The best way to observe the motion blur is to compare the highlights in the droplets, as the power reduces the length of the highlight shortens until around 1/32 power it is just a dot.

From the results of this experiment I rarely shoot droplets with the flash above 1/32 of full power to minimise the blur. At power levels higher than 1/16 the blur is clearly visible.

To do this the flashguns are positioned very close to the subject so I can use small apertures and a low iso setting.

Canon 580Ex flash gun 1/1 Power

Canon 580Ex flash gun 1/2 Power

Canon 580Ex flash gun 1/4 Power

Canon 580Ex flash gun 1/8 Power

Canon 580Ex flash gun 1/16 Power

Canon 580Ex flash gun 1/32 Power

Canon 580Ex flash gun 1/64 Power

Canon 580Ex flash gun 1/128 Power

10 Responses to Flash and Motion Blur

  1. Peter says:

    First of all I love you work it is truly outstanding.
    My question is what type/colour bowl/tray do you use to fill with water? I have tried black metal trays and white soup bowls. Any advice would be appreciated.
    Thanks
    Peter

  2. cy says:

    Just a note to mention that we, usually, are not interested in water drops falling down. We are interested in water splash. Once droplet has hit the water surface, it’s speed is greatly reduced, thus an extremely short flash duration may not be required. I have reduced my external flash’s duration considerably but the problem is that then the photo is underexposed. A very large aperture cannot be used as DOF is crucial. Much higher ISOs create noise, and shutter is irrelevant anyway. Dilemma!

    • photosbykev says:

      The speed of the rebounding water column and the collision with a 2nd droplet has approximately TWICE the impact velocity of a single falling droplet. You are struggling because the flashguns need to be positioned within 3-4″ of the splash so that you can use small apertures and low iso. Most of my droplet work is shot at f11-f16 and iso 200 and is correctly exposed.

      Kev

  3. Pingback: High speed shutter & flash sync

  4. Sudhakar says:

    @photosbykev
    Thanks Kevin for the response, will go through the link & come back to you incase of any more queries.

    Sudhakar

  5. Sudhakar says:

    Dear Kevin,
    This is a pretty good info for beginners like me to start on water drop work.

    I have tried doing some work, uploaded my pix at below link. Please comment on the same.
    http://picasaweb.google.co.in/sudhakar.yg/MyTableTopPix#

    I have been wondering on one thing, how are you able to get that splash of 2 droplets & get that umbrella kind of shape?
    Is this made using any different type of liquid or is it just the time at which you capture the event?
    If its at a specific time than how do you calibrate to it?
    I have not used any equipments to capture the droplets, I use only a remote switch (RS-80N3) with my Canon EOS30D to capture this image.

    I have been seeing these kind of images at quite a lot websites but is not able to figure it out.
    Please help me to understand.

    Once again thanks for sharing!!

    Sudhakar

  6. Brian Palmer says:

    thanks for posting this! I just started experimenting with photographing water drops most recent here: http://bit.ly/3ZgJL1 – This is great information to expand on so I can get bigger and better results. Your work is amazing Kevin!

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