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ISO: Balancing Light Sensitivity Underwater

This is Part 6 of a 10 part Natural Light Photography Series.

1/320, f/9, ISO 1000

ISO is one of the most critical settings in underwater photography, especially when shooting with natural light. It determines your camera’s sensitivity to light and plays a key role in achieving proper exposure. While increasing ISO can brighten your image, it also introduces noise, which can reduce image quality. In this blog, I’ll share my approach to setting ISO for natural light photography and explain why manual control is the way to go.

Why I Avoid Auto ISO

Some photographers rely on auto ISO to adjust their settings dynamically, but I’ve never been satisfied with the results underwater. Auto ISO often overcompensates, leading to images that are too bright or too noisy. Instead, I prefer to set my ISO manually and use my histogram to fine-tune my exposure. This gives me complete control and ensures my images are consistently well-balanced.

Starting Points for ISO

The amount of sunlight, water clarity, and depth all influence how I set my ISO. Here are my go-to starting points:

  1. Bright Sunlight with a Sandy Bottom:

    • ISO Setting: 400

    • Why: The sand reflects sunlight, providing plenty of natural light to work with.

  2. Deep Water with No Bottom in Sight:

    • ISO Setting: 800

    • Why: Without a reflective surface, less light reaches your subject, so a higher ISO compensates for the loss.

1/320, f/9, ISO 1000

Using the Histogram to Adjust ISO

Before finalizing my ISO, I rely on my histogram to check exposure. Here’s how I approach it:

  1. Perform a 360-Degree Spin:

    • I do a full turn in the water to observe how light changes depending on my angle to the sun. This helps me find a middle ground that works, even if I’m facing slightly toward the sun.

  2. Fine-Tune with the Histogram:

    • The histogram provides an objective way to evaluate whether my exposure is balanced, allowing me to adjust ISO as needed.

How to read your Histogram.

When to Adjust ISO

  • Increase ISO:

    • In low-light conditions, such as cloudy days, deep dives, or early morning/late afternoon shoots.

    • To freeze fast-moving subjects when a faster shutter speed is needed.

  • Decrease ISO:

    • In bright, shallow water with excellent visibility.

    • When you’re close to your subject and don’t need the extra light sensitivity.

1/320, f/9, ISO 1000

Practical Tips for ISO Underwater

  1. Start Low, Adjust Gradually: Begin with a lower ISO setting (e.g., 400) and increase as necessary based on light conditions.

  2. Minimize Noise: Keep ISO as low as possible while maintaining proper exposure to reduce graininess in your images.

  3. Test in Different Environments: Practice adjusting ISO in various conditions to better understand how your camera handles light sensitivity and noise underwater.

1/320, f/8, ISO 1000

The Power of Manual ISO

Controlling ISO manually gives you the flexibility to adapt to the ever-changing underwater environment. Whether you’re shooting in shallow tropical waters or deep, murky conditions, understanding how to adjust ISO effectively will ensure your images are sharp, vibrant, and properly exposed.

Coming Next

In the next blog, we’ll discuss focus points and how to use them to keep your subjects sharp, even when shooting blind with big animals. Stay tuned for tips on mastering focus in the dynamic underwater world!

THIS IS PART 6 OF A 10 PART SERIES.

PART ONE - Is Natural Light Photography Photography For You?
PART TWO - The Euphotic Zone! Your best friend.
PART THREE - Custom White Balance, Natural Lights Secret Weapon.
PART FOUR - Shutter Speed: Freezing Moments Underwater.
PART FIVE - Aperture: Achieving Sharpness and Depth Underwater
PART SIX - ISO: Balancing Light Sensitivity Underwater
PART SEVEN - Focus Points: Keeping Your Subject Sharp Underwater
PART EIGHT - The Histogram: Your Underwater Photography Lifeline
PART NINE - Post-Processing: Bringing Your Underwater Images to Life.
PART TEN - The Freedom of Natural Light Photography: A Connection to the Wild

Aperture: Achieving Sharpness and Depth Underwater

This is Part 5 of a 10 part Natural Light Photography Series.

Orcas off Baja. 1/320, f9, ISO 800.

Aperture, or f-stop, is one of the most important settings in underwater photography. It controls the amount of light entering your camera and determines your depth of field—the range of focus in your image. For natural light photography, where light is limited and animals are constantly moving, understanding how to set your aperture is essential for creating sharp, well-composed shots.

My Go-To Aperture Settings

For most of my underwater photography, I stick to an aperture range of f/8 to f/11. These settings provide enough depth of field to keep the entire subject—whether it’s a shark, whale, or dolphin—in focus, even when shooting wide-angle.

Why f/9 is My Preferred Setting:

  • It ensures critical features, like the eyes, remain sharp.

  • It gives enough depth of field to account for slight errors in focus, especially when shooting “blind” (holding the camera away from your body to get closer to the subject).

When to Adjust Aperture

  1. Over/Under Shots:

    • Setting: f/11 to f/14 (or higher)

    • Why: For split shots capturing both underwater and above-water scenes, a smaller aperture ensures both planes are in focus.

  2. Low-Light Conditions:

    • Setting: Open the aperture as wide as your lens allows (e.g., f/4 or f/2.8).

    • Why: In dim conditions, opening the aperture maximizes the light reaching your sensor, though this reduces depth of field.

Tiger Shark off Tiger Beach Bahamas, 1/320, f8, ISO 800

The Challenges of Big Animal Photography

When photographing large, fast-moving animals like sharks and whales, you often can’t look through the viewfinder. Instead, you’re shooting with your arms outstretched to get closer to your subject—a technique often referred to as “shooting blind.”

Every inch matters when using a wide-angle lens like an 8-15mm fisheye, as the best underwater images have minimal blue water between you and the animal.

By using a mid-range aperture like f/9, you can compensate for the challenges of shooting blind, ensuring that key features remain in focus even if your framing isn’t perfect.

A Safety Reminder

While getting close to your subject often leads to the best photos, always prioritize:

  • Your safety.

  • The well-being of the animal.
    No image is ever worth compromising the trust and safety of wildlife.

Practical Tips for Using Aperture Underwater

Bonito off Baja feeding on a sardine baitball. 1/500, f9, ISO 800

  1. Experiment with Depth of Field: Start with f/9 and adjust based on your subject and lighting conditions. For larger animals, a smaller aperture (f/11) can help ensure the entire subject is sharp.

  2. Pair Aperture with Shutter Speed: Remember, changing your aperture affects the amount of light entering your camera, so adjust your shutter speed and ISO to maintain proper exposure.

  3. Test Your Lens Limits: Practice with your lens to understand how it performs at different apertures. Wide-angle lenses are forgiving but still require attention to detail.

Whale Shark off Baja, Mexico. 1/320, f9, ISO 500

The Magic of Aperture in Natural Light

Aperture settings can make or break your underwater images. With the right adjustments, you can achieve sharp, vibrant photos that showcase the beauty of the underwater world. Whether you’re aiming for a detailed close-up of a shark’s eye or a dramatic over/under shot, understanding aperture is key to capturing the moment.

Coming Next

In the next blog, I’ll tackle ISO—a setting that can make or break your images in varying underwater conditions. Learn how to balance light sensitivity and noise to achieve the perfect exposure. Stay tuned!

THIS IS PART 5 OF A 10 PART SERIES.

PART ONE - Is Natural Light Photography Photography For You?
PART TWO - The Euphotic Zone! Your best friend.
PART THREE - Custom White Balance, Natural Lights Secret Weapon.
PART FOUR - Shutter Speed: Freezing Moments Underwater.
PART FIVE - Aperture: Achieving Sharpness and Depth Underwater
PART SIX - ISO: Balancing Light Sensitivity Underwater
PART SEVEN - Focus Points: Keeping Your Subject Sharp Underwater
PART EIGHT - The Histogram: Your Underwater Photography Lifeline
PART NINE - Post-Processing: Bringing Your Underwater Images to Life.
PART TEN - The Freedom of Natural Light Photography: A Connection to the Wild

Shutter Speed: Freezing Moments Underwater

This is Part 4 of a 10 part Natural Light Photography Series.

In underwater photography, your shutter speed plays a crucial role in capturing sharp, dynamic images. Whether you’re photographing the graceful glide of a shark or the lightning-fast movements of a dolphin, choosing the right shutter speed is essential. In this blog, I’ll share my approach to setting shutter speed for natural light photography and explain why it’s one of the most critical tools in your underwater arsenal.

The Basics of Shutter Speed Underwater

Shutter speed determines how long your camera’s sensor is exposed to light. A faster shutter speed freezes motion, while a slower shutter speed lets in more light but risks motion blur. In underwater photography, where both you and your subject are often moving, this balance becomes even more delicate.

Understanding Shutter Speed: From freezing fast motion to creating smooth, dreamy effects – master the art of light and movement.

When shooting with strobes, a common shutter speed is 1/125, but for natural light photography, it’s a whole different story. Your settings will depend on:

  • The subject’s speed and movement

  • The available light

  • Your ability to stay steady while shooting

My Go-To Shutter Speeds

  1. Slow-Moving Subjects (e.g., Tiger Sharks, whales):

    • Shutter Speed: 1/320

    • Why: Tiger sharks and whales move at a slow, deliberate pace, but both the animals and I are in motion. At 1/320, I can confidently capture their details without motion blur.

  2. Fast-Moving Subjects (e.g., Dolphins, Sea lions):

    • Shutter Speed: 1/500

    • Why: Dolphins and sea lions are incredibly fast and often unpredictable. A faster shutter speed ensures I can freeze their motion, even while swimming hard to keep up. For fast-moving animals, 1/500 is my absolute minimum. While I would prefer to go higher for an even crisper image, doing so often requires increasing the ISO, which can introduce too much noise into my photos. Finding the right balance is key when shooting in natural light underwater.

  3. Low-Light Conditions (e.g., Orcas in Norway):

    • Shutter Speed: 1/125 or lower (if necessary)

    • Why: In places like Norway, where sunlight is limited or non-existent during winter, slower shutter speeds are unavoidable. While this can lead to some blur or grain (due to higher ISO), it’s often the only way to get a usable image.

Why I Stick to 1/320 for Most Shots

For the wildlife I typically photograph—big, toothy animals like sharks—1/320 has become my magic number. It’s fast enough to freeze motion while still allowing enough light for a well-exposed image. Some might say it’s on the higher side, but for me, it strikes the perfect balance for sharp, detailed results.

When to Adjust Shutter Speed

  • Increase Shutter Speed: For faster animals or when shooting in bright conditions.

  • Decrease Shutter Speed: In low-light environments or when photographing slower-moving subjects.

Practical Tips for Underwater Shutter Speed

  1. Keep Your Camera Steady: Even the slightest movement can cause blur when shooting underwater. Practice controlling your breathing and staying as still as possible.

  2. Test and Adapt: Start with a base shutter speed (like 1/320) and adjust based on the animal and lighting conditions.

  3. Use Your Histogram: Check your histogram regularly to ensure your exposure is balanced, especially when adjusting shutter speed.

The Importance of Experimentation

Shutter speed isn’t a one-size-fits-all setting. It depends on your subject, the conditions, and your creative goals. The more you experiment, the better you’ll understand what works for your style of photography and the animals you love to capture.

Coming Next

In the next blog, I’ll dive into aperture—another critical setting for natural light photography. Learn how to achieve the perfect depth of field and ensure your subjects are always in focus, even when shooting blind. Stay tuned!

THIS IS PART 4 OF A 10 PART SERIES.

PART ONE - Is Natural Light Photography Photography For You?
PART TWO - The Euphotic Zone! Your best friend.
PART THREE - Custom White Balance, Natural Lights Secret Weapon.
PART FOUR - Shutter Speed: Freezing Moments Underwater.
PART FIVE - Aperture: Achieving Sharpness and Depth Underwater
PART SIX - ISO: Balancing Light Sensitivity Underwater
PART SEVEN - Focus Points: Keeping Your Subject Sharp Underwater
PART EIGHT - The Histogram: Your Underwater Photography Lifeline
PART NINE - Post-Processing: Bringing Your Underwater Images to Life.
PART TEN - The Freedom of Natural Light Photography: A Connection to the Wild