Making Beautiful Portraits Using Flash and High-Speed Sync (HSS)
High-Speed Sync (HSS) is a powerful flash technique that allows you to use flash at shutter speeds faster than your camera's sync speed (typically 1/200th or 1/250th of a second). This opens up a world of creative possibilities for portrait photography, particularly in bright sunlight.
Here's a breakdown of how to make beautiful portraits using flash and HSS:
I. Understanding the Basics
* What is HSS? In normal flash photography, your camera's shutter speed is limited to the sync speed because the entire sensor needs to be exposed when the flash fires. With HSS, the flash emits a rapid series of pulses instead of one burst. This allows the sensor to be lit as the shutter curtains move across it, enabling faster shutter speeds.
* Why Use HSS for Portraits?
* Overpowering the Sun: HSS lets you use wider apertures (like f/2.8 or f/1.8) in bright sunlight to achieve shallow depth of field and creamy backgrounds.
* Controlling Ambient Light: You can use fast shutter speeds to darken the background, creating a more dramatic and focused portrait.
* Freezing Motion: Fast shutter speeds combined with flash can freeze fast-moving subjects or details.
* Equipment Required:
* Camera: A camera that supports HSS.
* Flash: A flash that supports HSS. (Many modern speedlights and studio strobes offer HSS capabilities.)
* Trigger: A radio trigger that also supports HSS. (These communicate with the flash and camera to enable HSS.)
* Light Modifier: Softbox, umbrella, beauty dish, etc., to shape and soften the light.
* Optional: Light meter (helpful for accurate exposure).
II. Setting Up for HSS Portraits
1. Camera Settings:
* Mode: Aperture Priority (Av/A) is generally recommended for portraits. You choose the aperture for your desired depth of field, and the camera sets the shutter speed. Manual mode is also viable, offering full control.
* Aperture: Choose a wide aperture (e.g., f/1.4, f/2.8, f/4) for shallow depth of field and a blurred background. The exact aperture will depend on your lens and desired effect.
* ISO: Start with the lowest possible ISO (e.g., ISO 100) to minimize noise. You might need to increase ISO if you need a faster shutter speed than your flash can provide.
* White Balance: Set your white balance appropriately for the scene. Consider using a grey card for accurate color.
* Focus Mode: Use Single-Point AF or continuous AF (depending on the subject's movement) and focus on your subject's eyes.
2. Flash Settings:
* HSS Mode: Enable HSS mode on both your flash and your trigger. Refer to the manuals for your specific equipment.
* Flash Power: Start with a low flash power (e.g., 1/64 or 1/32) and increase it gradually until you achieve the desired exposure.
* TTL vs. Manual: TTL (Through-The-Lens) metering can work in HSS, but it's often more consistent to use manual flash power. TTL tends to drain batteries faster in HSS due to the constant firing of pre-flashes.
3. Light Modifier Setup:
* Choose Your Modifier: Softboxes and umbrellas create soft, diffused light, which is generally flattering for portraits. Beauty dishes create a slightly more specular, contrasty light.
* Position the Light: Experiment with different light positions (e.g., 45 degrees to the subject, directly in front, rim light). Consider using a reflector to bounce light and fill in shadows.
* Distance: The closer the light modifier is to your subject, the softer the light will be.
III. Taking the Shot
1. Metering:
* Meter the Ambient Light: With your flash turned off or set to minimum power, take a meter reading of the ambient light. Adjust your shutter speed until the background is slightly darker than you want it. This is the key to using HSS effectively – you're intentionally underexposing the ambient light. Look at the histogram on your camera to help.
* Adjust Flash Power: Now turn on your flash and increase the power until your subject is properly exposed. You can use a light meter for precise measurements, or simply use your camera's LCD screen and histogram to judge the exposure. Take a test shot and adjust accordingly.
2. Compose and Shoot: Compose your shot, focus on your subject's eyes, and take the photo.
3. Review and Adjust: Review the image on your camera's LCD screen. Pay attention to:
* Exposure: Is the subject properly exposed? Adjust the flash power if necessary.
* Background: Is the background as dark as you want it? Adjust the shutter speed if necessary.
* Depth of Field: Is the depth of field correct? Adjust the aperture if necessary.
* Light Quality: Is the light soft and flattering? Adjust the position or size of your light modifier if necessary.
IV. Tips and Tricks for Beautiful HSS Portraits
* Power Management: HSS requires a significant amount of flash power, which can drain batteries quickly. Use fresh batteries and consider an external battery pack.
* Flash Distance: The farther the flash is from your subject, the less effective it will be, especially in HSS. Keep the flash relatively close to your subject for best results.
* Practice: HSS can be tricky to master. Practice in different lighting conditions and with different subjects to get a feel for how it works.
* Consider ND Filters: If you're struggling to achieve a dark enough background even with the fastest shutter speeds, consider using a Neutral Density (ND) filter on your lens. This will reduce the amount of light entering the lens, allowing you to use even wider apertures in bright sunlight.
* Know Your Gear's Limitations: Some flashes and triggers have limitations regarding HSS power output at certain shutter speeds. Read the manuals thoroughly.
* Use a Reflector: A reflector is an inexpensive and effective way to bounce light back into the subject's face, filling in shadows and adding dimension. Silver reflectors provide a brighter, more contrasty fill, while white reflectors provide a softer, more natural fill.
* Watch the Shadows: Pay attention to the shadows on your subject's face. You may need to adjust the position of your light modifier or add a reflector to eliminate harsh shadows.
* Experiment with Light Ratios: The light ratio is the difference in brightness between the key light (the main light source) and the fill light (the light used to fill in shadows). Experiment with different light ratios to create different moods and effects.
V. Common HSS Problems and Solutions
* Uneven Exposure: This can happen if your flash isn't powerful enough or if the HSS signal is weak. Try increasing the flash power, moving the flash closer to the subject, or using a different trigger.
* Banding: Banding (horizontal lines in the image) can occur if the shutter speed is too close to the camera's limitations in HSS. Try slightly adjusting the shutter speed.
* Hotspots: Hotspots can occur if the flash is too powerful or too close to the subject. Try reducing the flash power or moving the flash farther away.
By understanding the principles of HSS and practicing your technique, you can create stunning portraits with beautiful backgrounds and perfectly exposed subjects, even in the brightest sunlight. Good luck!