Understanding Flash Zoom: How to Match Your Speedlight Zoom with Your Lens Zoom (and How It Works with Off-Camera Flash)
When you’re using a speedlight (external flash) to light your photos, there’s an important setting you should know about—your flash’s zoom function. Just like your camera lens, your flash has zoom settings that adjust how the light is spread across your scene. Understanding how to match the zoom on your speedlight with the zoom on your lens can make a big difference in how your images look.
We’ll cover how flash zoom works, when to adjust it, and why using the widest zoom setting is key when using off-camera flash with modifiers like softboxes.
What is Flash Zoom?
Flash zoom adjusts how the light spreads from your speedlight. When the flash zoom is set to wide (like 24mm), the light spreads out over a large area. When it’s set to narrow (like 105mm), the light becomes more focused, illuminating a smaller part of the scene.
Your camera lens works similarly, zooming in and out to change the field of view in your images. Ideally, your flash zoom and lens zoom should work together for the best lighting results.
When to Adjust Flash Zoom
Here’s an easy way to think about it: if you zoom in with your lens to capture a close-up shot, you’ll want your flash to zoom in too, so it concentrates light on your subject. When you shoot a wider scene, you’ll want your flash zoom to spread out as well, covering a larger area.
Why Flash Zoom Matters
Using the right flash zoom ensures that your subject is lit effectively. Here’s how different zoom settings affect your images:
1. Wide Flash Zoom (24mm or 35mm): The light spreads out over a larger area, which is perfect for group shots or wide-angle scenes where you need to light more of the environment. However, the light won’t be as strong since it’s spread out.
2. Narrow Flash Zoom (85mm to 105mm): The light is focused on a smaller area, which is ideal for zoomed-in shots, like portraits or product photography. The light will be stronger but more concentrated, which can sometimes look harsh if not controlled.
Matching Flash Zoom with Lens Zoom
Here’s a simple guide: your flash zoom should often match your lens zoom for consistent lighting. For example:
If you’re shooting with a 24mm lens, set your flash zoom to 24mm for even light distribution.
If you zoom in with an 85mm lens to take a portrait, set your flash zoom to 85mm so the light is focused on the subject.
Some speedlights automatically adjust their zoom to match your lens, but it’s still helpful to know how to set it manually in case you want to experiment or override the automatic settings.
Using Your Speedlight Off-Camera: Why Flash Zoom Matters Even More
When using your speedlight off-camera, especially with light modifiers like softboxes, umbrellas, or diffusers, the zoom setting becomes even more important.
Why You Should Set Your Flash to the Widest Zoom for Modifiers
When you attach a modifier like a softbox to your speedlight, your goal is to fill that softbox with light evenly. The softbox is designed to diffuse the light and spread it more softly across your subject, which reduces harsh shadows and creates a more flattering look.
To do this effectively, you’ll want to set your speedlight’s zoom to its widest setting (usually 24mm or lower). Here’s why:
Even Light Distribution: When your flash is zoomed out wide, it spreads light across the entire surface of your softbox or modifier. This allows the modifier to function properly by evenly diffusing the light.
Soft, Diffused Lighting: By filling the softbox with light, you avoid harsh hotspots or uneven lighting, giving your subject a smoother, more flattering look.
If you use a narrower zoom (like 85mm or 105mm) with a softbox, the light will only hit a small part of the softbox, creating uneven lighting and losing the benefit of the soft, wide light spread that the softbox is designed for.
Flash Zoom for Creative Effects
Once you’re comfortable with the basics, you can experiment with flash zoom to create different looks:
Wide Flash Zoom with a Narrow Lens Zoom: This spreads light around your subject, creating a soft, more ambient feel. It’s great for portraits where you want a broader, more even light.
Narrow Flash Zoom with a Wide Lens Zoom: This creates a spotlight effect, focusing intense light on your subject while keeping the background darker, which can add drama to your photos.
A Quick Recap for New Photographers:
1. Flash zoom adjusts how wide or narrow your light spreads—wide zoom spreads light over a larger area, while narrow zoom focuses it on a smaller spot.
2. Match your flash zoom to your lens zoom for balanced, even lighting. A wide lens needs a wide flash zoom, and a zoomed-in lens needs a narrower flash zoom.
3. When using off-camera flash with a modifier like a softbox, set your flash to the widest zoom (24mm or lower) to fill the modifier with light evenly for soft, flattering results.
4. Experiment with zoom settings to create different lighting effects, like ambient, soft light or focused, dramatic light.
Understanding how flash zoom works—whether on or off-camera—gives you greater control over your lighting and the final look of your photos. Try out different settings on your next shoot, especially if you’re using a softbox, and see how zooming your flash affects your results!