Want to learn how to get the most out of this kind of setup underwater - not just technically, but in terms of reading light and animal behavior - the AquaExposure training covers exactly that. ---

To learn how to get the most out of your underwater gear, check out the AquaExposure training.

Test Xiaomi 15 Ultra: Underwater Photography Review and 2026 Score

A few years ago, talking about a smartphone for serious underwater photography was a polite way to change the subject. Sensors were too small, RAW either unavailable or unusable, and available housings didn't offer enough control to work properly. The 15 Ultra changes that calculation.

Xiaomi built this phone around a 1-inch Sony LYT-900 sensor, a Leica Summilux f/1.63 optic, and a quad-camera system covering 14 mm to 100 mm in pure optical reach - with a 5 cm minimum focus distance on the 200MP periscope telephoto.

For an underwater photographer working in natural light, those are exactly the three criteria that matter: sensor size for low light, RAW for color correction in post-processing, and minimum focus distance for macro.

That's what this test covers. No kitchen photography. Just what the 15 Ultra delivers at 20 meters depth, no flash, with only available sunlight.

AquaExposure Score: 4.1/5

Best suited for: Android underwater photographers who want a compact, versatile system with RAW access and macro capability, primarily in tropical or temperate water.

Less ideal for: Regular dives in cold water (below 15°C) or users who want a fully native RAW video workflow without a third-party app.

Underwater, light drops fast. Every meter of depth absorbs part of the visible spectrum, and small sensors - the kind in most smartphones - struggle to compensate. The 15 Ultra's 1-inch sensor is a direct answer to that problem.

With the Summilux f/1.63 aperture on the main wide camera, the phone captures roughly 60% more light than a smartphone with a 1/1.8-inch sensor. In practice, that translates to usable images at ISO 3200 where other devices start drowning in noise.

The 200MP periscope telephoto deserves specific mention for underwater macro photographers. The 5 cm minimum focus distance combined with 200MP resolution lets you frame a 2 cm nudibranch with enough detail for large-format printing, without disturbing the animal.

Technical deep-dive - B1 specs Main sensor: Sony LYT-900, 1-inch, f/1.63, 23mm, dual pixel PDAF, 4-axis OIS + hybrid EIS. 70mm telephoto: 50MP, 1/2.51", f/1.8, PDAF (focus from 10 cm), OIS. 100mm periscope telephoto: 200MP, 1/1.4", f/2.6, multi-directional PDAF, OIS. 14mm ultrawide: 50MP, 1/2.76", f/2.2, PDAF. Minimum focus distance field-tested: 5 cm (documented by Divevolk). Burst and RAW buffer: high speed confirmed, precise buffer size not published by Xiaomi. Shutter latency: "zero shutter lag" in auto mode. In RAW Pro: estimated 50-100 ms. Leica Summilux flare: certified anti-reflection coating - light under normal conditions, not tested against direct surface sun. B1 Score: 4.0/5

Underwater, auto white balance is blind. Water absorbs red first, then orange, then yellow. A photo taken at 10 meters without correction looks like a blue-green wash regardless of the scene. The only way to correct this properly is to shoot RAW and reconstruct colors in post-processing.

The 15 Ultra shoots native RAW in Leica Pro mode, on the main sensor. That's a genuine step forward from most Android phones that require a third-party app to access raw files. Underwater color corrections become far more precise starting from a clean DNG file.

For video, native Log (H.265 10-bit, Dolby Vision) covers the needs of 80% of diving videographers. For the remaining 20% who want pure RAW video, MotionCam Pro is available on Android GMS and works inside the Divevolk housing via the touchscreen.

The Leica partnership isn't cosmetic. The Leica Authentic Look and Leica Vibrant Look profiles add a colorimetric calibration that produces more faithful JPEGs outside of RAW mode - useful when shooting burst and you don't want to post-process 500 images.

Technical deep-dive - B2 specs RAW available: Native DNG in Leica Pro mode on the main sensor (50MP full resolution). Other sensors: RAW available but pixel-binned to 12.5MP. Bit depth: 12-bit documented (some sources mention "UltraRAW 16-bit," not confirmed in official specs). Manual WB in video: Kelvin control available natively in Leica Pro mode. Max video codec: H.265 10-bit Log + Dolby Vision native (4K at 60 fps). RAW video via MotionCam Pro (Android GMS). Third-party app: MotionCam Pro available and stable on Android GMS. Color science: Certified Leica partnership (Summilux lenses, Authentic/Vibrant profiles). B2 Score: 4.6/5

A 50MP DNG file weighs around 70MB. An active 50-minute dive produces between 200 and 400 frames. Over a 3-dive day, that's 40 to 80GB of raw files. The 15 Ultra in 512GB configuration absorbs that without issue.

The key strength here is the USB-C 3.2 Gen 2 connector paired with UFS 4.1 storage. Between dives, plugging in a portable SSD via OTG takes a few minutes to offload 60GB. No laptop needed on the boat - the phone and a compact SSD are enough.

The absence of a microSD slot is worth noting for photographers who manage their files with swappable cards.

Technical deep-dive - B3 specs Internal storage: 256GB, 512GB, or 1TB (UFS 4.1). No microSD slot. Connector: USB-C 3.2 Gen 2 + DisplayPort + OTG. Field transfer speed estimate: 500+ MB/min with NVMe SSD via USB 3.2 Gen 2. RAW photo 3-dive workflow: 600 photos x 70MB = 42GB. Manageable on 512GB without intermediate transfer. 4K@60fps Log video workflow: approximately 1GB/min. 3 dives x 50 min = 150GB. Field transfer recommended. B3 Score: 4.2/5

This is where the 15 Ultra requires caution. The 6M42 aluminum chassis with the IceLoop system (5,100mm² vapor chamber) is excellent at dissipating Snapdragon 8 Elite heat on land. Underwater, that same system becomes a problem.

A high thermal-conductivity chassis reaches water temperature quickly. If the water is 14°C and the air inside the housing is at ambient temperature (25°C before entering the water), the temperature differential creates condensation on the inner lens port. Same mechanism as glasses fogging when moving from cold air to warm.

In tropical water (above 25°C), the gap is small and the risk is marginal. In the Mediterranean in October or the North Atlantic, vigilance is needed. The fix is simple: pre-acclimatize the sealed housing in the shade for 10 to 15 minutes before water entry, so the air inside approaches ambient outdoor temperature before contacting cold water.

Technical deep-dive - B4 specs Chassis material: 6M42 high-strength aluminum (frame) + Xiaomi Shield Glass 2.0 (screen). Internal cooling: Xiaomi 3D Dual-Channel IceLoop, 5,100mm² vapor chamber. Thermal conductivity: High (aluminum + vapor chamber). Real condensation risk in cold water. Resistance certification: IP68 (1.5m / 30 min). Xiaomi Guardian Structure. No MIL-STD-810 certification. Cold water behavior (below 15°C): condensation possible without pre-acclimatization. Score drops to 1/5 in that scenario. B4 Score: 2.5/5 (tropical water assessment) - systematic pre-acclimatization protocol recommended

The 5,410 mAh Si-C (silicon-carbon) battery in the global 15 Ultra isn't just a marketing figure. Silicon-carbon chemistry stores more energy at equivalent volume than standard Li-Ion, and holds up better at low temperatures.

Over a 3-dive day with the screen running continuously inside the housing, expect 60 to 80% battery consumed. The phone finishes the day with reserve. The EU-certified 1,000 cycles mean the battery retains 80% capacity after roughly two and a half years of intensive use.

Technical deep-dive - B5 specs Capacity: 5,410 mAh Si-C (global) / 6,000 mAh Si-C (China version). Chemistry: Silicon-Carbon (Si-C) - better cold-weather resistance and higher energy density than Li-Ion. Documented cycles: 1,000 cycles before 20% capacity loss (official EU label). Active use score (GSMArena): 16h13. B5 Score: 4.8/5

Avant chaque session plongée, pensez à vérifier votre batterie externe. Utilisez notre comparateur de batteries portables pour choisir la power bank adaptée à votre caisson et votre autonomie.

The 15 Ultra's AF system combines multi-directional PDAF across all sensors (dual pixel on the main, telephotos, and ultrawide - multi-directional on the 200MP), Laser AF support, and Snapdragon 8 Elite AI algorithms.

In clear water, it's excellent. The phone locks onto a small, moving subject with a reliability few smartphones reach. Focus Peaking is accessible in Leica Pro mode, letting you verify precise focus on a macro subject.

The element to watch is Laser AF. In turbid or particle-laden water (plankton, suspended sediment), a Laser system can lock onto nearby particles rather than the subject. The AquaExposure scoring penalizes this when manual Laser deactivation isn't confirmed - and Xiaomi doesn't document that option.

In practice, the multi-directional PDAF is robust enough for most situations. The limitation will appear in specifically murky dives, where an iPhone Pro with LiDAR (a physical measurement independent of visibility) would have the edge.

Technical deep-dive - B6 specs AF technologies: Laser AF (infrared ToF) + dual pixel PDAF (main, 70mm, ultrawide) + multi-directional PDAF (200MP). LiDAR: absent (available on iPhone Pro only as of 2026). Laser deactivation: not documented by Xiaomi. Focus Peaking: available in Leica Pro mode. AI particle rejection PDAF: likely (Snapdragon 8 Elite), not explicitly documented. B6 Score: 4.0/5

Housing quality makes or breaks an underwater photography system, even with the best smartphone in the world. On this point, the 15 Ultra benefits from the best available option for an Android phone.

The DIVEVOLK SeaTouch 4 Max Platinum is machined from aerospace aluminum, rated to 60m, with a touchscreen working underwater down to 40m depth (SeaTouch gel technology). The internal space is sized for the thick camera modules of current flagships, and the Xiaomi 15 Ultra fits perfectly.

The critical point for this phone specifically: full touchscreen access means all Leica Pro mode functions work without restriction. Switch between lenses, adjust ISO, set white balance in Kelvin, trigger the shutter - everything works exactly as it does on land.

Technical deep-dive - B7 specs Housing: DIVEVOLK SeaTouch 4 Max Platinum. Material: Aerospace aluminum. Depth rating: 60m. Touchscreen: functional to 40m (SeaTouch gel technology). App compatibility: full access including MotionCam Pro and Leica Pro. Indicative price: €420 (housing only). B7 Score: 5.0/5

To ensure your smartphone fits securely and compare interior volume, make sure to check if your model's dimensions fit in this housing.

Available Housings

For the 15 Ultra, the reference option is the DIVEVOLK SeaTouch 4 Max Platinum (€420, 60m rated, aerospace aluminum, full touchscreen). Universal soft housings exist at lower price points but without the control level or certified depth of the Platinum.

ARMOR-X mounts exist for lighter use (snorkeling, surface activities) but are not suited for dives beyond 3 to 5 meters.

Field Workflow

For a 3-dive day shooting RAW photos:

• 300 photos x 70MB = 21GB of DNG per dive
• Day total: approximately 60 to 90GB
• 512GB capacity: covers 5 to 8 full days without offloading
• Backup transfer: OTG SSD via USB 3.2 Gen 2 - 60GB in under 5 minutes

For 4K@60fps Log video, plan an offload between dives starting from the 256GB version.

Key Watch Points

Condensation in cold water: make pre-acclimatization of the sealed housing standard practice (10 to 15 minutes in the shade before water entry). This eliminates 90% of the risk. In very cold water (below 12°C), add a silica gel packet inside the housing.

RAW on telephoto lenses: in Leica Pro mode, RAW on sensors other than the main (70mm, 200MP, ultrawide) is available but pixel-binned to 12.5MP. For full-resolution 200MP macro, switch to standard mode for JPEG, or enable MotionCam Pro for RAW video.

Laser AF and turbid water: in dives regularly featuring sediment-heavy water, test AF behavior on static subjects first to calibrate expectations.

The Xiaomi 15 Ultra is the most capable Android smartphone I've tested for natural-light dive photography. Not the overall winner - the iPhone 17 Pro Max stays ahead on autofocus in turbid water thanks to physical LiDAR, and on condensation risk thanks to its titanium chassis. But on everything else - 1-inch sensor optical quality, native Leica RAW, 200MP macro at 5 cm, and an Si-C battery that lasts a full day - the 15 Ultra is hard to beat at this price.

It has a genuine photographer's personality. Not a phone that takes good photos by accident, but a system designed to give control to whoever knows how to use it. Leica Pro mode responds directly to the way you think about natural light underwater: manual exposure control, not algorithmic guesswork.

For an Android underwater photographer looking for a compact system with a serious housing and genuine RAW access, the 15 Ultra with the Divevolk Platinum is probably the best available combination in 2026.

Final score: 4.1/5

Not sure which one to choose? Use our underwater camera gear comparator to compare this device with other tested models.

Pour aller plus loin sur la condensation et la surchauffe, lisez notre article dédié : Surchauffe et buée du smartphone dans un caisson sous-marin.