An underwater macro photograph can be full of beautiful detail and still leave the viewer wondering where to look. The eye is soft, the interesting feature falls behind the plane of focus, or the background is so sharp that it competes with the subject.
Sometimes the opposite happens. A tiny, precise area of focus gives the image its character, while everything around it falls away.
The skill is deciding what needs to be clear before trying to make every part of the frame sharp.
Choose the detail that carries the image
Before changing a camera setting, ask what the photograph is about. For a fish portrait, the near eye often needs to hold attention. For a nudibranch, that might be the rhinophores, the curve of the body or its relationship with the surface it is crossing. A shrimp among the arms of an anemone might need enough detail in both subject and shelter to make the encounter understandable.
There is no rule that every frame needs a perfectly sharp eye. An abstract image may depend on a single line, texture or colour transition. Intentional movement may make a soft edge part of the story. What matters is that the viewer can feel where the photographer intended their attention to settle.
Boz Johnson’s Diamond Squid defensive pose offers a useful counterexample to the sharp-eye rule. The 2026 Underwater Photographer of the Year judges praised the macro image even though its eyes were not in clear view. The pose and lighting carry the picture. It does not follow that soft eyes always work; it shows that the point of attention can be elsewhere.
Check the result at a useful magnification on your camera screen, if your equipment allows it. An image that looks sharp as a small thumbnail may reveal missed focus when enlarged. If the critical detail is soft, identify the cause before taking more frames. Was focus placed behind it? Did you or the subject move? Was the depth of field too shallow for the angle you chose?
Understand the thin plane of focus
The closer and more magnified the photograph, the less depth appears acceptably sharp. An animal that looked comfortably three-dimensional to the eye may extend beyond the camera’s narrow zone of focus.
Alex Mustard’s You have been warned makes the challenge visible. He photographed a tiny, moving nudibranch in Lembeh with a high-magnification lens. The Wildlife Photographer of the Year account notes that depth of field remained limited even at a small aperture. His eye-level viewpoint matters as much as the technical struggle: it lets the animal meet the viewer on its own scale.
A smaller aperture, represented by a higher f-number on cameras with aperture control, can bring more of the subject into acceptable focus. It also reduces the light entering the lens, and very small apertures can soften fine detail through diffraction. The most useful setting depends on your camera, lens, magnification and available light. There is no single underwater macro f-number that solves every subject.
Camera angle matters just as much. If the feature you want to show lies along a plane that faces the camera, more of it may appear sharp at the same aperture. Photograph a long subject steeply from the front, and its head and tail may fall at very different distances from the lens. Move to a more side-on viewpoint, where you can do so without disturbing the animal or habitat, and you may gain the detail you wanted without changing the aperture at all.
Working distance changes the result too. Backing away a little can make focus easier and include more context. A closer, more magnified view can reveal astonishing detail, but it demands finer control of focus and camera position. More magnification is useful only when it serves the picture.
Separate missed focus from movement
Softness does not always mean that autofocus chose the wrong place. A gentle surge can shift the camera and subject relative to one another between focusing and exposure. A small animal can move its head, antennae or fins. A camera can drift forward by a fraction of a centimetre as the photographer breathes.
Start by settling into a stable, safe position with continuous, relaxed breathing. Do not hold your breath or brace the camera against living reef or other sensitive habitat. If the water is moving, watch its rhythm and release the shutter during a steadier moment. If your camera allows you to move the focus point, put it on the detail that matters instead of focusing centrally and making a large change in framing afterwards.
Review the frame. If the wrong part of the subject is crisp, adjust the focus point or your position. If the entire frame is smeared, consider movement, exposure time and the balance between ambient light and artificial light. A strobe can freeze the part of the exposure it illuminates, while ambient light recorded during a slower shutter exposure may still leave a visible blur. Under continuous light, shutter speed becomes especially important for moving subjects.
The remedy follows the cause. Repeating the same settings and movement usually repeats the same mistake.
Let the background help
Depth of field is also a storytelling choice. A softly rendered background can separate a small subject from a busy reef. More depth can show a fish in its shelter, a shrimp among its host’s arms or the surface a nudibranch is crossing.
In Natalie Yarrow’s Crowded House, the shrimps living within a barrel sponge grow progressively softer deeper in the frame. She chose a wide aperture to create that receding focus, and the judges singled it out as a reason the eye moves through the photograph. The blur is doing work: it conveys the depth and crowded nature of the shelter.
Neither treatment is automatically stronger. A clean blur may isolate the subject beautifully but remove the information that makes the encounter interesting. A detailed habitat may tell the story but overwhelm a small focal point. Ask what the viewer needs to understand, then choose how much of the surroundings should remain legible.
Weiwei Zeng’s An Artistry Coral Home for Scorpion Shrimp offers another answer. A tiny shrimp almost disappears within the repeated coral pattern. The surrounding structure is part of what the viewer needs to see to understand both the animal’s camouflage and the photograph’s visual idea. A blurrier background would tell a different story.
You can change that balance with aperture, camera angle, distance and lighting. Change your own position only where there is room to do so responsibly. Leave the animal and everything around it as you found them.
Try one deliberate focus exercise
On a suitable dive, choose an undisturbed subject that can be photographed without crowding it. Work within a short, considerate encounter rather than making a long series of flashes or pursuing an animal that moves away.
- Make one frame with a clear point of attention, such as an eye or another defining feature.
- Review it at magnification. Check where focus actually landed and whether movement softened the image.
- If conditions allow, change one thing: your focus point, a small camera-angle adjustment, your distance or your aperture.
- Make another frame and compare. Did the change improve the story as well as the sharpness?
The aim is not to collect dozens of versions. It is to learn what each adjustment does while keeping the encounter calm. You can practise the same decisions on stationary, non-living details before approaching a sensitive subject.
Sharpness is a decision
A strong photograph does not have to render every millimetre in perfect detail. It does need its technical choices to feel purposeful. The critical feature should be clear when clarity is part of the story; softness should contribute something when it is used creatively. A competition result can offer an example, but it cannot turn one photographer’s aperture or focus point into a rule for every image.
The strongest solution is often a modest one: place focus carefully, choose an angle that suits the subject, and let the rest of the frame support that choice. If you plan to enter a competition, check its own rules for permitted capture and editing methods, including focus stacking.
The question to ask is simple: what must the viewer see clearly, and why?