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Focus Points: Keeping Your Subject Sharp Underwater

This is Part 7 of a 10 part Natural Light Photography Series.

Mako Shark off Cabo San Lucas, MX. 1/400, f/9, ISO 800

In underwater photography, especially with fast-moving or large animals, getting sharp images can be a challenge. This is where understanding and effectively using your camera’s focus points becomes critical. The right focus settings can make all the difference in ensuring your subject—not the distractions around it—is captured clearly.

Why Wide Dynamic Autofocus Works Best

For big animals like sharks, whales, or dolphins, I always use a wide dynamic autofocus area. Shooting underwater often means you’re working without the luxury of looking through the viewfinder. Instead, you’re shooting “blind,” with your arms extended to get closer to the subject.

Using a single-point autofocus in these situations significantly increases the risk of missing your shot, as it’s nearly impossible to keep that one focus point on a moving target. A wide focus area ensures the camera tracks your subject even when you’re not perfectly aligned.

Limit the Autofocus Area

While wide autofocus is essential, I don’t recommend activating all your focus points across the frame. Instead, I narrow the focus area to the center region, activating 9 to 15 focus points. This approach minimizes the chance of your camera locking onto distractions, such as:

  • Fish swimming around your subject

  • Particles in the water

  • Other divers or objects in the background

Sailfish hunting sardine baitball off Baja, MX. 1/640, f/8, ISO 1600

Silky shark with pilot fish off Cabo San Lucas, MX. 1/320, f/10, ISO 800

By concentrating your focus area, you increase the chances of keeping your primary subject—the big animal—sharp and detailed.

Common Challenges with Focus Points

Big animals often have smaller companions, like fish swimming alongside sharks, that can steal your camera’s focus. This is similar to photographing a bird in a tree and accidentally focusing on the branch instead. By narrowing the focus area, you ensure your subject remains the priority.

Another challenge is rapid movement. Wide dynamic autofocus helps here by tracking your subject across multiple points, even as they shift position or change direction.

Practical Tips for Using Focus Points

  1. Customize Your Focus Area: Experiment with limiting your autofocus points to the center region to see what works best for your shooting style.

  2. Communicate with Dive Buddies: If you plan to use their gear (like tanks or fins) as a focus reference during custom white balance or framing, let them know beforehand to avoid confusion. So it doesn’t get weird.

  3. Practice Shooting Blind: Familiarize yourself with positioning and angles so you can effectively capture sharp images even without looking through the viewfinder.

Great White off Guadalupe Island, MX. 1/320, f8, ISO 400.

The Debate: Single Point vs. Wide Dynamic

Some photographers advocate for single-point autofocus, but this approach works best when you’re shooting through the viewfinder and can track your subject. For underwater photography, where conditions are more dynamic and you’re often shooting from less stable positions, wide dynamic autofocus provides greater flexibility and reliability.

Final Thoughts

Mastering focus points is an essential skill for underwater photographers, especially when working with large, fast-moving animals. By using a wide dynamic autofocus area with a limited central region, you can strike the perfect balance between precision and adaptability, ensuring your subjects are always sharp.

Striped marlin hunting sardines off Baja Mexico. 1/640, f/8, ISO 1600