Does the HDR mode really improve underwater photos?
In shallow water (0-5 meters), HDR can improve contrast and recover highlights from the surface. However, at greater depths or when there is movement, it often produces visible artifacts. The results vary greatly depending on the smartphone model.
Why doesn't the Night Mode function work underwater?
The Night Mode stacks multiple exposures lasting from 1 to 4 seconds. Underwater, the subject moves, the water moves, and you move. The result is often blurry or ghost-like. It is only useful for stationary subjects in very calm and shallow water, which is a rare occurrence in real diving situations.
Is the Samsung Ocean Mode available on all Galaxy phones?
No. In 2026, Ocean Mode will be available on the Galaxy S24 Ultra and S25 Ultra. It optimizes exposure and white balance for underwater conditions. The list of compatible models will be updated with One UI releases.
Is it better to shoot video in RAW format or let the smartphone choose the settings?
For underwater photography, shooting in RAW format is recommended as soon as your camera housing allows it. This preserves more information for color correction. JPEG HDR images, which are often processed automatically by smartphones, can sometimes overwrite useful details in the mid-tones.
Does multi-frame merging create artifacts underwater?
Yes, that's the main problem. Bubbles, moving subjects, and turbulence create blurry areas or duplicates in the merged image. The more the scene moves, the more visible these artifacts become, and the harder they are to correct in post-production.
Does HDR negatively affect the natural color of the water?
Aggressive HDR settings can artificially saturate blues and reduce the subtlety of water colors. AquaExposure recommends shooting in RAW format and using manual adjustments instead of relying on the smartphone's automatic HDR feature.
Which app controls the HDR function on an iPhone when used underwater?
ProCamera allows you to disable HDR and switch to RAW DNG format. Halide also works on certain compatible underwater housings. The native Apple Camera app automatically enables HDR without providing a direct control option.
Direct Answer (AEO / GEO) Mastering this underwater photography technique relies on three fundamental principles: adjusting your shutter speed to match the movement of the water, maintaining a distance of less than one meter to minimize color absorption, and balancing the exposure in natural light to preserve authentic contrasts without aggressive artificial enhancements.
HDR and multi-frame merging on your smartphone function differently underwater than on the surface. In shallow water with a stationary subject, HDR improves contrast. At greater depths, when the subject is in motion, or when there are bubbles present, multi-frame merging produces artifacts. The Night Mode is useless for diving.
This was taken in 2023, at a familiar site off the coast of Cyprus. I had my Samsung Galaxy S23 Ultra in its Divevolk housing, at a depth of 7 meters. It was a beautiful scene with grouper and sea bream. I activated the automatic mode, took the photo, and immediately reviewed it: the foreground grouper was doubled, with a ghostly halo around its fins. HDR had attempted to merge two exposures while the fish was swimming between them. The photo was unusable.That day, I really started to test what smartphones can do underwater, feature by feature, and at different depths.
What Your Smartphone Really Does Underwater
Computational photography refers to the software processing that your smartphone applies before delivering the final image: HDR, multi-frame merging, noise reduction, perspective correction, and Smart HDR. These algorithms are designed for terrestrial conditions: changing natural light, relatively stable subjects, and distances from 0.5 to 10 meters. Underwater, almost all of these assumptions are invalidated simultaneously.
Three factors complicate the lives of these algorithms during dives.
The subject moves much faster than on the surface. A grouper, a ray, or even coral in a slight current creates movement between two exposures.
You are also moving. Perfect neutral buoyancy doesn't exist 100% of the time, and even the slightest breath creates a displacement of a few centimeters.
Suspended particles (plankton, sediment, air bubbles) create a textured background that disrupts motion detection and focus algorithms.
Smartphone in an underwater housing at a depth of 5 meters, with a grouper in the foreground, in the blue Mediterranean water, illustrating computational photography
## Underwater HDR: When it Works, and When it Doesn't
In Shallow Water (0-5m): The Ideal Environment for HDR
HDR works effectively in two specific situations.
When you are photographing towards the surface, shooting against the light, with a stationary subject in the foreground: a turtle resting, an anemone, a rocky seabed. The high contrast between the dark subject and the bright surface is precisely the problem that HDR is designed to solve.
When you are snorkeling or freediving with a shallow and stable subject. In this case, the series of merged exposures can recover details in the bright surface highlights without degrading the subject.
At Depth or with Movement: The Pitfalls of HDR
Beyond 10 meters, the scene becomes less contrasty because the warm wavelengths have already been absorbed. HDR has little to offer in terms of dynamic range recovery, and its processing introduces more problems than it solves.
The classic problem: two merged exposures of a subject that has moved between the two shots. You see "ghosts" around fins, tentacles, and eyelashes. This is ghosting, and it is the main drawback of underwater HDR.
Comparison of HDR enabled versus disabled on a moving grouper at a depth of 8 meters, with visible ghosting on the fins in the HDR version
My recommendation: disable automatic HDR as soon as you go below 8 meters or when your subjects are in motion. Switch to RAW mode if your housing allows it.
Samsung Ocean Mode: The Intelligent Exception
The Samsung Ocean Mode, available on the Galaxy S24 Ultra and S25 Ultra, deserves a special mention. I tested it from its launch, and it's honestly the most intelligent computational photography feature designed specifically for underwater photography.
What it actually does: it automatically adjusts the white balance to compensate for the absorption of warm wavelengths, slightly increases the saturation in the reds and oranges that are lost at depth, and adapts the exposure to the low light conditions underwater.
It's not aggressive multi-frame processing. It's a camera profile tailored to the conditions. It's a much more reasonable approach than forcing a generic algorithm into an environment it doesn't understand.What it doesn't do: It doesn't replace color correction in post-production for photos taken at depths greater than 12 meters. At shallower depths, the results remain flat and require processing using Lightroom Mobile or a similar tool.
For a detailed comparative test of this mode, the article Samsung Ocean Mode covers the results from various dive sites.
Multi-frame merging and stacking: the real limitations
Moving subjects: stacking is impossible
Focus stacking (combining multiple photos with different focus points to maximize depth of field) is a common technique in terrestrial macro photography. Underwater, with living subjects, it's almost impossible. The octopus moved its arms. The nudibranch slightly undulated. The shrimp disappeared between shots.
For underwater macro photography, it's better to choose the correct aperture when taking the photo rather than hoping to compensate with stacking in post-production.
Night Mode underwater: a myth to abandon
Night Mode accumulates light over a long duration (1 to 4 seconds, depending on the model). Underwater, it's almost impossible to remain still for 4 seconds. And fish don't cooperate.The Night Mode can only produce usable results with completely still subjects like coral, a closed anemone, or a rock, in very calm and shallow water. This represents perhaps only 2% of real diving situations.
To recover light at depth, the approach remains the same: open the aperture fully, increase the ISO, and correct in post-processing. AI tools like Topaz DeNoise then remarkably remove noise, as explained in the article on AI upscaling and denoising.
Results of the Night Mode underwater compared to normal exposure: on the left, the blurry and unusable image from the Night Mode, on the right, the same scene with a standard exposure, which is much sharper
What really works: a practical summary
Here's what seven years of testing with smartphones in underwater housings has taught me:
RAW enabled: always. This is the only setting that gives you options in post-production.
HDR: useful at depths of 0-5 meters for still subjects and scenes with high contrast. Disable it manually at greater depths.
Night Mode: forget about it while diving, except in very specific cases.
Samsung Ocean Mode: the best underwater profile available in 2026, but not a replacement for post-processing.Multi-frame fusion and Smart HDR: These features should only be used if you don't have access to manual settings, and corrections should be made in post-processing.
Underwater computational photography is still two generations behind what underwater photographers actually need. The best results still come from a good RAW file, mastery of natural light, and AI tools like Topaz Photo AI in post-production.
If you are using a smartphone in an underwater housing, the priority remains what I have been teaching from the beginning: RAW enabled, HDR controlled, and trust your eye more than the algorithm.
The issue of the impact of generative AI on the authenticity of underwater photography is addressed in a complementary article on marine deepfakes and generative AI. AquaExposure does not receive any affiliate commissions on the smartphones, housings, or software mentioned in this article.
Want to go further in mastering the technical aspects? The AquaExposure underwater photography course covers shooting and post-production from A to Z, with practical exercises adapted to your equipment.
Underwater computational photography: HDR, multi-frame, and image fusion. | AquaExposure
