Does the HDR mode really improve underwater photographs?
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 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's only useful for stationary subjects in very calm and shallow water, which is a rare occurrence during actual dives.
Is the Samsung Ocean Mode available on all Galaxy devices?
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 is updated with each One UI release.
Is it better to shoot in RAW format or let the smartphone choose its 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. The JPEG HDR format, which is often processed automatically by smartphones, can sometimes overwrite useful details in the mid-tones.
Does multi-frame stacking create artifacts underwater?
Yes, that is the main problem. Bubbles, moving subjects, and turbulence create blurry areas or duplicates in the merged image. The more movement there is in the scene, the more visible these artifacts become, and the harder they are to correct during post-processing.
Does HDR 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 automatic HDR feature of your smartphone.
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 Apple's native Camera app automatically enables HDR without providing a direct control option.
HDR and multi-frame merging on your smartphone function differently underwater than they do on the surface. In shallow water with a stationary subject, HDR can improve contrast. However, at greater depths, when subjects are moving, or when there are bubbles present, multi-frame merging produces artifacts. The Night Mode is useless for diving.
This occurred 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 spot with grouper and bream. I activated auto mode, took the photo, and immediately reviewed it: the foreground grouper was doubled, with a ghostly halo around its fins. The HDR had attempted to merge two exposures while the fish was moving between them. The photo was unusable.
That day, I began to truly test what smartphones can do underwater, feature by feature, at different depths.
What Your Smartphone Actually Does Underwater
Computational photography refers to all of the software processing that your smartphone applies before presenting you with the final image: HDR, multi-frame merging, noise reduction, perspective correction, Smart HDR. These algorithms were 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 operation of these algorithms during dives.The subject moves much faster underwater than it does on the surface. A grouper, a ray, or even coral in a slight current can create movement between exposures.
You are also moving. Perfect neutral buoyancy doesn't exist 100% of the time, and even the smallest breath creates a displacement of just a few centimeters.
Suspended particles (plankton, sediment, air bubbles) create a textured background that disrupts motion detection algorithms and autofocus.
Smartphone in an underwater housing at a depth of 5 meters, with a grouper in the foreground, blue Mediterranean water, demonstrating computational photography
Underwater HDR: When it works, and when it doesn't.
In shallow water (0-5m): Ideal conditions for HDR
HDR works well in two specific situations.
When you are photographing towards the surface against the light with a stationary subject in the foreground: a turtle resting, an anemone, or a rocky bottom. The high contrast between the dark subject and the bright surface is exactly 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 highlights of the surface without degrading the subject.
At depth or when subjects are moving: The pitfalls of HDRBeyond 10 meters, the scene becomes less contrasted because the warmer wavelengths have already been absorbed. HDR has little to offer in terms of dynamic range, and its processing introduces more problems than it solves.
The classic problem: two exposures merged onto a subject that moved between the shots. You see "ghosting" around fins, tentacles, and even eyelashes. This is ghosting, and it's the main drawback of HDR underwater.
Comparison of HDR enabled versus disabled on a moving grouper at 8 meters depth, 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 moving. Switch to RAW mode if your housing allows it.
Samsung Ocean Mode: A Smart 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 honestly, it's the most intelligent computational photography feature designed specifically for underwater photography.
What it actually does: It automatically adjusts white balance to compensate for the absorption of warmer wavelengths, slightly increases saturation in reds and oranges that are lost at depth, and adapts exposure to the low light conditions underwater.This isn't aggressive multi-frame processing. It's a camera profile adapted to the conditions. This is a much more reasonable approach than forcing a generic algorithm onto an environment it doesn't understand.
What it doesn't do: replace color correction in post-production for photos taken at depths greater than 12 meters. At shallower depths, the results are still flat and require processing using Lightroom Mobile or a similar tool.
For a detailed comparative analysis of this mode, the article Samsung Ocean Mode covers the results from several dive sites.
Multi-frame Fusion 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 live 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, holding still for 4 seconds is almost impossible. 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 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 Night Mode underwater compared to normal exposure: on the left, the blurry and unusable image from 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 smartphones in underwater housings has taught me:
RAW enabled: always. This is the only setting that gives you options for post-processing.
HDR: useful at depths of 0-5 meters on still subjects and scenes with high contrast. Disable it manually at greater depths.
Night Mode: forget about using 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: Let the smartphone decide only if you don't have access to manual settings, and correct 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 photos is addressed in a complementary article about 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.
