Motion blurs are created through a combination of movement and long exposures. Essentially, you are capturing color and light for the duration that your sensor is exposed to light. This gives you three fundamental options: Either you move the light, you move your subjects… or you move your camera.
- Moving your light around when the shutter is open creates streaks… think light painting (interested in learning? click here) Light painting to me has always looked a little cartoony and surreal.
- Moving your subjects around creates nice interesting abstract blurs. If the subjects are humanoid in nature, the movements become irregular and controlled motions like dance appear as beautiful geometrical figures that appear in the middle of a chaotic centre.
- Moving your camera around means that your subject can stand absolutely still and that you, the shooter are in control of the lines that are painted. The results of camera motion is most often a geometrical line of some sort as a slight camera movement has a major impact on your image.
Setting up the shot:
Step 1: Set up ambient light to keep background dark.
We had a bunch of warm tungsten stage lights available to us. This meant that we could spread them out evenly over a large surface area without touching the backdrop. We threw in an entire row on the back of our stage and a couple in front to ensure that we’d also get some nice light on our subjects from the front too.
By keeping the beams relatively tight, and angling them downwards, we could ensure that the light wouldn’t bleed too much onto the background.
The lights we had were quite bright so we were able to set my D800E up to shoot at an iso of 50 at an aperture of f5.6. Very nice. This meant that even if my subjects were in motion, I would still be able to keep them in focus if they only moved from left to right.
Step 2: Set up the flashs to light up the foreground
As mentioned earlier, I wanted to have some clean cinematic and dramatic light. I opted for two large directional light sources that would be able to wrap around my dancers without affecting the background –> Extra large gridded softboxes. Flash power was set by matching what I wanted to see frozen.
Tip: When calibrating your flash power to match your camera settings, put your shutter speed up to max sync speed (normally between 1/200th or 1/250th of a second) to make sure the image isn’t affected by the ambient light.
Step 3: Set up your flashes to sync at the end of your exposure
As mentioned earlier, flashes will define at which point your subjects become “frozen” in place in your image. If you’re looking to produce a realistic image, logically the movement trails should happen in the “past” not in the future and as such, you want the trails to follow your subjects, not lead. To achieve this, set your flashes to trigger at the end of your exposure… in camera lingo, that means REAR SYNC FLASH.
Step 4: Experiment !
Once everything is already set up and ready to go is to shoot, recalibrate, shoot recalibrate and shoot again. If possible, frame larger rather than tighter to make certain that the amazing shot gets some pieces of movement cut off. Since the flash occurs at the end of the exposure, try to slightly overestimate the exposure time for the dancers to complete their movement.
Note: when testing, try to avoid circular movements as they tend to stack up on one another!
Step 5 : Photoshop!
The cool part about motion trails is that you can combine them with other motion trails quite easily in photoshop! If you did a good job exposing your shots with a dark background, placing the resulting images in “screen” blend mode in photoshop will make your job a lot easier!