Understanding the Concept
The core idea is to fire a flash multiple times during a single long exposure taken with your camera. Since the ambient light is typically very low, the flash will act as the primary source of illumination for each instance it fires. This "freezes" the subject's position at each flash firing, resulting in multiple images of the subject within the same frame.
What You Need:
* DSLR or Mirrorless Camera: You need manual control over your camera settings (shutter speed, aperture, ISO, flash power).
* External Flash (Speedlight or Strobe): This is essential. The built-in flash on your camera usually doesn't have the necessary control or power. A flash with adjustable power settings is ideal.
* Tripod: Crucial for keeping the camera steady during the long exposure, preventing unwanted motion blur in the background.
* Remote Shutter Release (Optional but Recommended): Minimizes camera shake when starting the exposure.
* Dark Environment: A dimly lit room or shooting at night works best. You want the flash to be the dominant light source.
* Subject: Person, object, anything you want to capture in multiple instances.
* Flash Trigger (If Needed): If using multiple flashes or off-camera flash, a trigger (radio or optical) is often necessary.
Camera Settings:
* Mode: Manual (M) mode.
* Shutter Speed: This is the key. Set it to a slow shutter speed that covers the duration of your desired effect (e.g., 1 second, 2 seconds, 5 seconds, or even longer depending on how much movement you want). Experiment!
* Aperture: Start with a smaller aperture (higher f-number like f/8 or f/11) to ensure more of the scene is in focus, and to reduce the amount of ambient light captured. Adjust as needed based on the available light and desired depth of field.
* ISO: Keep the ISO as low as possible (e.g., ISO 100 or 200) to minimize noise.
* Focus: Manually focus on your subject. Autofocus won't work well in a dark environment.
* White Balance: Set it to Flash White Balance or a custom white balance to get accurate colors from the flash.
Flash Settings:
* Mode: Manual (M) mode. This gives you precise control over the flash power.
* Power: Start with a low power setting (e.g., 1/32, 1/64, or even lower) and increase it if needed. The goal is to freeze the subject with each flash burst without overexposing. Lower power settings also allow for faster flash recycle times.
* Zoom: Adjust the zoom head of the flash to focus the light on your subject.
* Flash Recycle Time: Consider the recycle time of your flash. A faster recycle time means you can fire the flash more frequently.
Steps:
1. Set Up: Mount your camera on the tripod and frame your shot. Position your subject.
2. Camera Settings: Configure your camera as described above (Manual mode, slow shutter speed, small aperture, low ISO).
3. Flash Settings: Configure your flash as described above (Manual mode, low power).
4. Darken the Environment: Turn off or dim the lights as much as possible.
5. Focus: Manually focus on your subject.
6. Take the Shot:
* Using Flash Directly on the Camera: Press the shutter release (or use a remote shutter release) to start the exposure. Manually fire the flash multiple times during the exposure by pressing the flash's test button. Alternatively, if your flash has a stroboscopic/multi mode, enable it and set the frequency and number of flashes. (See "Using Stroboscopic Mode" below.)
* Using Off-Camera Flash: If using off-camera flash, you'll need a way to trigger the flash remotely. You can use a radio trigger, an optical trigger, or a sync cable. Trigger the flash manually (or through the stroboscopic mode if available) during the exposure.
7. Subject Movement: Between each flash firing, have your subject move to a slightly different position. The amount of movement will determine the spacing between the multiple images.
8. End the Exposure: Once you've fired the flash the desired number of times and your subject has moved accordingly, let the exposure complete.
9. Review and Adjust: Check the image on your camera's LCD screen. Adjust your camera settings (aperture, ISO) and flash power based on the results. If the image is too bright, reduce the flash power or close the aperture. If the image is too dark, increase the flash power or open the aperture. Experiment with different shutter speeds to control the amount of motion blur between the flash exposures.
Using Stroboscopic Mode (Multi Mode)
Some flashes have a stroboscopic (or "multi") mode. This mode allows you to pre-set the flash frequency (Hz) and the number of flashes. This is ideal for creating evenly spaced multiple exposures.
1. Enable Stroboscopic Mode: Refer to your flash's manual to learn how to enable and configure stroboscopic mode.
2. Frequency (Hz): This determines how many flashes per second will be fired. A lower frequency means more time between flashes.
3. Number of Flashes: Set the total number of flashes you want to fire during the exposure.
4. Power: Adjust the power setting accordingly. You might need to reduce the power significantly in stroboscopic mode to avoid overexposure.
5. Trigger the Exposure: Start the long exposure on your camera. The flash will automatically fire the pre-set number of times at the specified frequency.
Tips and Tricks:
* Practice: It takes practice to get the timing and settings right. Don't get discouraged if your first few attempts aren't perfect.
* Background: A plain, dark background will help isolate your subject and make the multiple exposures stand out.
* Subject Clothing: Consider the clothing your subject is wearing. Solid, light-colored clothing will reflect the flash well.
* Light Modifiers: Experiment with using light modifiers like softboxes or umbrellas to soften the light from the flash. This can create a more pleasing and even illumination.
* Motion Blur: If you want to add some motion blur between the flash exposures, increase the shutter speed.
* Off-Camera Flash Placement: Experiment with different flash positions to create interesting lighting effects. Place the flash to the side, behind, or above your subject.
* Color Gels: Adding color gels to your flash can create interesting color effects.
Example Scenarios:
* Capturing a dancer's movements: Capture a dancer in various poses within a single frame, showing their fluidity and energy.
* Highlighting a product: Show different aspects of a product in a single image, rotating it between flashes.
* Creating a surreal effect: Have a subject "appear" and "disappear" by stepping into and out of the frame between flashes.
* Ghosting Effect: Use very low flash power combined with longer delays to create subtle ghosting effects.
Troubleshooting:
* Image is too bright: Reduce flash power, close the aperture, or decrease the ISO.
* Image is too dark: Increase flash power, open the aperture, or increase the ISO.
* Motion blur is too much: Decrease the shutter speed, use a faster flash recycle time.
* Motion blur is not enough: Increase the shutter speed.
* Flash isn't firing: Check your flash settings, battery level, and trigger connection.
By understanding the concepts and experimenting with different settings, you can create stunning and unique multiple flash exposure images. Have fun and be creative!