Underwater photography opens up an entirely different world — coral reefs pulsing with colour, marine life moving through shafts of sunlight, and abstract patterns created by light refracting through water. It is one of the most technically demanding genres in photography, requiring specialised gear, an understanding of how light behaves below the surface, and strong swimming skills. Check out our underwater photography gear guide for more details. But the rewards are extraordinary: images from a realm that most people never see firsthand.
Essential Gear for Underwater Photography
Underwater Housing
The most critical piece of equipment is a waterproof housing for your camera. Housings are pressure-rated enclosures, usually made of polycarbonate or aluminium, that seal your camera and lens inside while giving you access to all essential controls through mechanical buttons, dials, and levers.
Polycarbonate housings are lighter, less expensive, and suitable for snorkelling and shallow dives. Aluminium housings are built for serious diving, rated to depths of 60 to 100 metres, and offer more precise control ergonomics. Both types use O-ring seals that must be meticulously maintained — a single hair or grain of sand on the O-ring can cause a catastrophic flood that destroys your camera.
For casual underwater shooting, waterproof compact cameras and action cameras like the GoPro are an accessible starting point. They sacrifice image quality and control compared to a housed mirrorless or DSLR system, but they let you experience underwater photography without a significant investment.
Lenses and Ports
Underwater housings use interchangeable lens ports — dome ports for wide-angle lenses and flat ports for macro lenses. Wide-angle lenses (10-17mm fisheye or 16-35mm rectilinear) are the workhorses of underwater photography because you need to shoot as close to your subject as possible to minimise the amount of water between the lens and subject, which reduces sharpness and colour. Macro lenses (60mm or 100mm) excel for small subjects like nudibranchs, seahorses, and coral polyps, where getting close is easy and background water is less of a factor.
Underwater Strobes and Lights
Artificial light is essential underwater because water absorbs colour as you descend. Red disappears within the first 5 metres, then orange, then yellow. By 20 metres, everything looks blue-green without artificial light. Underwater strobes (flash units) restore the full colour spectrum to your subjects. Most underwater photographers mount two strobes on articulating arms positioned wide apart to reduce backscatter — the reflection of light off suspended particles in the water.
Video-focused underwater shooters use continuous LED lights instead of strobes. These also serve as focus lights for still photography, helping your camera lock focus in dimly lit conditions.
Camera Settings Underwater
Water changes the rules of photography in ways that surprise land-based shooters. Settings that work perfectly on the surface may produce poor results at depth.
Aperture: For wide-angle reef scenes and large marine life, shoot between f/8 and f/11 to balance depth of field with light gathering. For macro subjects, f/16 to f/22 provides the depth of field needed to get a tiny subject fully in focus, especially when using strobes that provide enough light to compensate for the narrow opening.
Shutter speed: Your maximum flash sync speed (typically 1/200s to 1/250s) is the upper limit when shooting with strobes. For ambient-light-only shots, use 1/60s to 1/125s and stabilise yourself against a reef structure or the sea floor. For fast-moving subjects like sharks, dolphins, or schooling fish, prioritise shutter speed at 1/250s or faster and raise ISO to compensate.
ISO: Start at ISO 200 to 400 with strobes. For ambient-light work or deep dives where strobes cannot reach, push ISO to 800 to 1600. Modern sensors handle the noise well, and slight noise is preferable to motion blur from a slow shutter speed in current.
White balance: When shooting with strobes, set white balance to approximately 5000K to 5500K (flash/daylight). For ambient-light-only images, use a custom white balance or shoot in RAW and correct the heavy blue-green cast in post-processing. Some photographers use a red filter on their lens for ambient-light video to partially compensate for red absorption.
How Light Behaves Underwater
Understanding underwater light is the key to consistently good results. Water is roughly 800 times denser than air, and this density affects light in three critical ways:
- Colour absorption. Water absorbs wavelengths starting with red, then progressing through orange, yellow, and green as depth increases. By 10 metres, reds are almost entirely gone. By 30 metres, the world is monochromatic blue-green. Strobes positioned close to your subject restore the absorbed colours.
- Scatter and backscatter. Particles suspended in the water — plankton, sand, sediment — scatter light in all directions. If you aim your strobes straight ahead, light bounces off these particles back toward the camera, creating bright white spots called backscatter. Position strobes out wide and angled slightly outward to light the subject from the sides rather than the front.
- Refraction and magnification. Light bends when it passes from water through the flat glass of a lens port, making subjects appear about 25% larger and 25% closer than they actually are. Dome ports correct this distortion for wide-angle lenses by creating a virtual image that the lens can focus on properly.
Underwater Photography Techniques
Wide-Angle Reef and Marine Life
The golden rule of wide-angle underwater photography is to get as close as possible. Every centimetre of water between your lens and the subject reduces contrast, sharpness, and colour. Use a fisheye or ultra-wide lens, approach your subject slowly and calmly (thrashing scares marine life and stirs up sediment), and fill the frame. Shoot upward when possible to place the subject against the brighter water column or sunburst rather than against the dark ocean floor.
Macro Underwater
Underwater macro photography is one of the most rewarding specialisations. The ocean is full of tiny, bizarre, and vibrantly coloured creatures that are invisible to the casual observer — nudibranchs, pygmy seahorses, mantis shrimp, and countless species of coral polyps. A 60mm or 100mm macro lens paired with a flat port brings these subjects to life. Use a narrow aperture (f/16 to f/22) for depth of field, position your strobes close for maximum colour saturation, and practice precise buoyancy control — touching the reef is harmful to the ecosystem and stirs up debris.
Snorkelling and Shallow Water
You do not need scuba certification to start shooting underwater. Snorkelling in shallow water — reef flats, tide pools, cenotes, and clear tropical lagoons — puts you in beautiful, well-lit environments where ambient light is strong and colourful. A waterproof compact camera or an action camera is often sufficient. The key technique is to swim slowly, breathe calmly through your snorkel to avoid disturbing sediment, and use the bright overhead sunlight to your advantage by shooting downward onto colourful reef or upward through the water surface for dramatic Snell’s window effects.
Gear Maintenance and Safety
- Inspect O-rings before every dive. Remove the O-ring, clean it and the groove with a lint-free cloth, inspect for nicks or hairs, apply a thin film of silicone grease, and reseat it carefully. This is the most important maintenance ritual in underwater photography.
- Rinse immediately after every dive. Soak your housing in fresh water for 15 to 30 minutes after saltwater use, pressing buttons and turning dials to flush salt from the mechanisms. Salt crystallisation causes corrosion and jammed controls.
- Test before committing your camera. On the first dive with a new or newly assembled housing, seal it without the camera inside and descend to check for leaks. A moisture alarm inside the housing can give early warning before a full flood.
- Dive skills come first. Master your buoyancy, air consumption, and comfort in the water before adding camera equipment. A distracted photographer with poor buoyancy is a danger to themselves, other divers, and the marine environment.
Post-Processing Underwater Images
Underwater images almost always need post-processing. The most common adjustments are white balance correction (removing the blue-green cast from ambient-light shots), increasing contrast (water reduces contrast significantly), and recovering colour in areas beyond strobe reach. Selective colour adjustments in the red and magenta channels can bring back warmth in mid-water areas. Backscatter spots can be removed with the healing brush.
Shoot in RAW format without exception. The extreme colour shifts and dynamic range challenges of underwater photography make RAW processing essential — JPEG images from underwater are almost always unusable without significant editing headroom.