Working with dancers is always fun and i’ve wanted to use the multi-flash feature of Canon Speedlites for some time. When a good pal of mine (and a fine choreographer) was setting up a new website we both wanted to create some interesting images that referenced dance but also the concept of motion.
Catching a dancer in a great move or mid-jump makes for a great shot but on this occasion we wanted to unfreeze the dancer as much as we could without resorting to film. The Multi feature on canon Speedlites offer the abilty to strobe away in the darkness and effectively created multiple stills for as long as the camera shutter is open.
Both number of flashes and frequency can be dialled into the speedlite. The frequency is expressed in Hz – and the minimum level is 1Hz – so the minimum gap between flashes will be one second. You can dial in a lot of flashes but the flash unit and batteries will get very tired so its’ best to stick to around 5 or six flashes.
Here we have five flashes taken at a rate of 8Hz – which means each of the five images above is 1/8 second apart.
The camera shutter is open for well over a second but the opening of the shutter triggers the start of the flashes. It’s effectively a single exposure but the flashes take care of what registers on the sensor – so as long as your subject is moving the frame won’t get too messy!
By limiting flashes to a group of just five we were able to capture the start of a move in one frame and the finish of a move in another – then by overlaying one shot on another we obtained the whole move – without overworking the flash units
Canon limit the power of the flash when used in multimode to 1/128 of full power. This is so the flash unit doesn’t melt in your hand / implode or break. I’m joking because there’s a fail-safe cut out anyway to prevent this happening but it would be kicking in all the time if the flash power was not limited in this way. The idea is to keep shooting and not have to wait for your flash to recover.
Another way to get more in the frame is simply by using both our dancers at the same time. The picture above is a single frame with five flashes – but two dancers moving away from each other at centre of frame.
Because the shutter is also open for some time a light or torch can also be used to create streaks across frame.
Of course if you then turn a light on the dancers the open shutter creates a motion blur from one movement to the next:
Here we triggered the flash units manually in an attempt to capture the beginning middle and end of a move with motion blur between points. I’m not mad on these sort of pictures – the motion blur is interesting but the look is cluttered and messy. With some experimentation we could probably do better but we chose instead to concentrate on the multi-flash mode pictures.
I wanted to keep the aperture down to about f9 to keep things sharp and allow the dancer freedom movement. With a flash power of 1/128 though this required a high ISO to compensate and noise was inevitable. This is exacerbated by having a shutter that’s open over a 5 second period of time….. the pictures had a fair degree of noise in them when looked at closely.
I eliminated noise with Niks Dfine2 which is free as a plug in to Photoshop and does the job rather well.