Use your unit’s strobe function to achieve rapid-fire flash and capture incredible staccato action.
A pulsing flash that fires lots of times during a long exposure can create a stop-motion effect by freezing the action multiple times as the subject moves through the frame. It’s an interesting technique to try on any moving subject and it is known as stroboscopic flash. All you need is a dark space, a tripod and a speed light with a stroboscopic or ‘multi’ mode.
There are three distinct ways that timing plays a part. First there’s the timing of the flash – you can choose the number of flashes and determine how quickly they fire, so you’ll get varying results depending on the flash count and frequency.
There’s a good deal of trial and error involved in nailing a pose since actions that might look graceful in real time can result in a jumbled mess when used with stroboscopic effect so timing and flow of the subject’s motion is key.
There can be dramatic changes depending on the split second that the shutter button is engaged – shooting the same sequence twice will most likely yield different results – so there is an art to pressing the shutter button at the right moment.
But part of the charm here is that it is unpredictable. Until you look down at the LCD after the exposure you simply won’t know what you’re getting. But, the results are definitely worth it when the lighting, posing, and timing come together in harmony.
Set The Exposure
Exposure is the starting point of this process. Take a couple of test shots with your camera set to manual, shutter speed at around 1 second, aperture to f/11 and ISO100. Close down the aperture to lower the ISO if the background is too bright.
Control The Flash Count
Most speed lights enable you to set two strobo controls; the Hz (Hertz) setting controls the flashes-per-sec, and the flash count determines total flashes. With flash count 10 at 8 Hz, you’ll get 10 bursts over 0.8 secs. Dividing the Hz by the count will give you the shutter speed.
Position The Light
You can illuminate the edge of the subject by placing the light behind the subject to one side. You’ll need to keep the effect from looking too muddled so this part of the process will enable you to emphasize the shape of the subject while still leaving the shadow areas.
Your flash power will be lower the more flashed there are per second. You may need to bring the flash closer or adjust the exposure to compensate for the fact that higher Hz and higher flash counts mean lower output. Try increasing your ISO or opening up the aperture if it looks too dark.
Try different poses with your subject as the results of strobo flash are unpredictable. Ask the subject to keep the body still and move the arms or have them move from one side to another. Fluid motion works best, as it means the various flashes will be more evenly spaced.
Trial and Error
A stroboscopic session will involve its fair share of problem solving and messy misfires. It’s about finding unity between the positioning of the lights, the posing, and the number of flashes. Experiment with the number of flashes as things can often look very busy.
Local Adjustments in Post
To enhance contrast and boost the exposure you can use Photoshop of Lightroom when editing the images. Bits of the pose may not have been caught by the flash so the adjustment brush is useful for lightening those areas. You can paint over the areas you want to enhance by setting up the tool with positive Exposure and Clarity.
Convert to Mono
A black-and-white conversion is a great simplifier, so it’s definitely one to try out here. A stroboscopic effect can sometimes look too busy in colour. In Lightroom or Camera Raw, you can experiment with the different black-and-white presets in the Basic Panel.
Try a Composite
It’s possible to combine several poses with a simple background. This is best done in Photoshop; you can drag and drop the three images into one document and position with the Move tool, then set the blend mode to Lighten, add a layer mask and paint with black to blend them together.
Add Another Flash!
Why not add a second burst of flash? You could try syncing a second speed light with the first so that they both fire in unison, or alternatively pop it manually during the exposure. It adds extra light to one moment in the pose.
You can add shape and definition to your subject by adding an extra single burst, fired manually by pressing the ‘test’ button towards the end of your second-long exposure.
Words by Elijah (Content Marketer) via Digital Camera World.