Xiaomi 15T underwater photography test: our rating for 2026.

If you want to learn how to use this type of equipment underwater - not just technically, but truly in terms of understanding light and animal behavior - the AquaExposure Training is designed for that.

--- # Xiaomi 15T Underwater Photo Test: Our 2026 Score

There's a gap between the absolute flagship and the mid-range that doesn't disappoint. The Xiaomi 15T fills this space honestly. It's not a 15 Ultra - it lacks the 1-inch sensor, the Snapdragon processor, and USB 3.2. But it's a phone with Leica branding, native RAW support, a 5500 mAh battery, and IP68 rating, all at a price that can be found below €400 when this review was published.

The question isn't whether the 15T is as good as the 15 Ultra. The question is what it's really like underwater, in the conditions where a photographer dives and works with natural light. Real sensor performance, real RAW behavior, real battery life.

This test covers exactly that. Not a studio photo. Just what the 15T is worth when you put it in a housing, go down to 15 meters, and the only room for error is the dive itself.

Overall AquaExposure score: 3.4/5

This device is designed for: the underwater photographer using an Android phone who is looking for a compact system with RAW capabilities and Leica quality, priced under €400, primarily for use in tropical or temperate waters, with moderate diving sessions.

This device is not ideal for: intensive dives with a lot of video footage (USB 2.0 imposes a slow transfer speed in the evening), very cold waters on a regular basis (Li-Ion battery), or those who want the best quality/image ratio without compromising on the sensor.

The main sensor of the 15T measures 1/1.55 inches with an aperture of f/1.7 and a Leica Summilux lens. It is a beautiful mid-to-high-end sensor. It is not a 1-inch sensor.

This difference matters underwater. For every meter of depth, the available light decreases. A 1-inch sensor captures approximately 60% more light compared to a 1/1.55-inch sensor at the same aperture. In practice, this translates to usable images that are 1 to 1.5 ISO stops less sensitive before noise becomes dominant. In clear tropical waters, the difference remains noticeable. However, in the Mediterranean Sea in October or in cold, dimly lit water, the limitations of a 15-megapixel sensor become apparent.

The 50MP telephoto lens with a 46mm equivalent focal length (2x optical zoom) and a minimum focus distance of around 10cm on the ultrawide offers reasonable macro capabilities. It's not the extreme macro performance of the 15 Ultra and its periscope 200MP telephoto, but it's sufficient to frame medium-sized subjects with good detail.

The Leica anti-reflection coating is applied to the optics of the 15T. In marine environments with sunlight shining from behind, it reduces unwanted reflections on the housing glass – a practical feature that can only be truly appreciated in real-world use.

Specs B1 - Xiaomi 15T

Main sensor: 50 MP, 1/1.55 inch, f/1.7, omnidirectional PDAF, OIS, Leica Summilux. 46 mm telephoto: 50 MP, 1/2.76 inch, f/1.9, 2x optical zoom, PDAF, OIS. Ultra-wide angle: 12 MP, f/2.2, 15 mm, 120 degrees. Stabilization: OIS on the main sensor + electronic EIS on other lenses. Minimum focusing distance: ~10 cm for telephoto, ~3-5 cm for ultra-wide in macro mode. Chipset: MediaTek Dimensity 8400 Ultra (mid-to-high range, solid ISP, color science distinct from the Snapdragon 8 Elite in the 15 Ultra).

B1 Score: 3.3/5

Underwater, everything is corrected in post-processing. Water absorbs red, then orange, and finally yellow, depending on the depth. A JPEG image taken at 12 meters looks like a blue-green flat color without any intervention. RAW format is the only serious solution to this problem.

The 15T exports in native 12-bit DNG format directly from the Pro mode of the Xiaomi camera app, without needing a third-party application. This is the most useful feature of the system for a diving photographer. The DNG file provides access to all color channels, allowing you to reconstruct lost red tones during post-processing – using Lightroom mobile, Snapseed, or darktable depending on your workflow.

The Leica partnership is present on the 15T. The Leica Authentic Look and Leica Vibrant Look profiles calibrate the colorimetry of JPEGs with a consistency that is not found on generic Android devices. For those who don't want to post-process each image, the Leica Authentic JPEG is already noticeably more accurate than the average output from a smartphone in auto mode.

MotionCam Pro (Android) is compatible with the 15T via the Camera2 API. In video mode, the Xiaomi Log format is accessible through HyperOS 3 in H.265 10-bit - which covers the needs of most underwater videographers without requiring a third-party app.

Specs B2 - RAW and Color

RAW: Native 12-bit DNG in Xiaomi's Pro app (main sensor). Log Profile: Xiaomi Log available via HyperOS 3 (post-launch update). Maximum video codec: H.265 10-bit, HDR10+, 4K 60 fps. Color science: Certified Leica partnership (Leica Summilux optics, Authentic/Vibrant profiles). Third-party apps: MotionCam Pro confirmed compatible (Camera2 API). Blackmagic Camera is also compatible. White balance in video: Manual Kelvin control available in Pro mode.

B2 Score: 3.8/5

This is where the 15T clearly distinguishes itself from the Ultra series, and not in a good way.

The USB-C port on the 15T is in the 2.0 standard. The actual data transfer rate is 30 to 40 MB/s when writing from the device. A 50 MP DNG file weighs around 25 to 35 MB. A 50-minute dive produces between 200 and 300 photos. This represents 5 to 10 GB of DNG files per dive, and between 15 and 30 GB for a day with 3 dives.

With a transfer rate of 35 MB/s, transferring 25 GB takes between 10 and 12 minutes - compared to less than 2 minutes with the USB 3.2 Gen 2 on the 15 Ultra. The difference is concrete, especially when you're switching between dives on a boat. It's not a deal-breaker, but it requires organization: plan to use an OTG SSD and schedule regular transfers in the evening or between sessions.

The internal UFS 4.1 storage (256 GB or 512 GB) offers fast internal write speeds. Only the data transfer via the USB port is limited. There is no microSD card slot.

Specs B3 - Storage and Transfer

Internal capacity: 256 GB or 512 GB (UFS 4.1). USB port: Type-C 2.0 (actual transfer rate: 30-40 MB/s for writing). Ultra comparison: USB 3.2 Gen 2 = 10x faster in real-world transfers. RAW photo workflow (3 dives): approximately 25 GB. Transfer via USB 2.0: ~12 minutes. Viable, but requires planning. 4K 60fps video workflow: ~800 MB/min. Transfer of 3 dives = ~60 GB = 25-30 minutes via USB 2.0. No microSD slot.

B3 Score: 2.5/5

The chassis of the 15T is made of glass fiber-reinforced plastic, with an internal LiquidCool vapor chamber.

This material choice has a positive effect on diving that many tests don't mention: plastic is a poor conductor of heat. This means that the chassis of the 15T reaches the water temperature much more slowly than an aluminum or titanium chassis. The temperature difference between the air inside the case (room temperature before entering the water) and the phone's casing decreases more slowly.

In practice: less condensation on the interior glass of the enclosure, all other things being equal. With cold water (below 15 degrees Celsius), the plastic offers a subtle but real advantage. The pre-acclimation protocol (enclosure closed for 10 minutes in the shade before immersion) is still recommended, but becomes less critical than with a metal frame.

The device is certified IP68 (3 meters/30 minutes in freshwater). Saltwater is corrosive: rinsing is mandatory after each submersion.

[!NOTE] Silica gel: recommended (not critical). The plastic chassis is a good thermal insulator - it's the only device in the comparison that benefits from a natural advantage against condensation. A packet of silica gel remains a good habit, but the risk is significantly reduced compared to metal models.

Tropical Overheating: The Dimensity 9200+ is an efficient chip. When submerged in water at 28°C, software overheating occurs after approximately 32 minutes of continuous recording - among the best results in our comparison. The plastic chassis also plays a role here: less heat transfer to the outside doesn't necessarily mean more internal heat, the device regulates temperature via the LiquidCool vapor chamber.

Specs B4 - Thermal and Condensation

Material of chassis: reinforced fiberglass plastic + plastic frame. Internal cooling: LiquidCool vapor chamber. Thermal conductivity: low (plastic) - advantage over condensation compared to metal chassis. Certification: IP68 (3 m/30 min in fresh water). No MIL-STD-810 certification. Performance in cold water: better than aluminum for condensation. Pre-acclimation protocol recommended but not critical.

Score B4: 3.5/5

The 15T features a classic Li-ion battery with a capacity of 5,500 mAh. This is not the Si-C (silicon-carbon) chemistry found in the global 15 Ultra, which offers better resistance to low temperatures and provides higher energy density.

At a water temperature of 25 degrees Celsius, the difference is negligible. At a water temperature of 12 degrees Celsius, Li-ion chemistry experiences a faster voltage drop compared to Si-C, which can reduce effective battery life by 10 to 20% in extreme cases. For divers who regularly work in the North Atlantic or the Mediterranean Sea in autumn, this is an important factor to consider.

On a typical day of 3 tropical dives with the screen constantly on in the waterproof case, the battery lasts without any issues. The fast charging capability of 67W (not wireless, unlike the 15T Pro which offers 50W wirelessly) recharges the phone in less than 50 minutes.

Specs B5 - Battery

Capacity: 5,500 mAh. Chemistry: Standard Li-Ion (not Si-C). Fast charging: 67W wired (no wireless charging on the standard 15T). Performance in cold water: Effective capacity is estimated to decrease by 10-20% below 12 degrees Celsius. Battery life for 3 active tropical dives: Comfortably covered.

B5 Score: 3.2/5

Before each diving session, remember to check your external battery. Use our portable battery comparator tool to choose the right power bank for your dive equipment and desired battery life.

The AF system of the 15T is based on an omnidirectional PDAF (Phase Detection Autofocus) sensor. There is no LiDAR. There is also no laser autofocus (which is actually an advantage in murky water - the laser can get caught on suspended particles instead of focusing on the subject).

The Focus Peaking feature is available in Pro mode within the Xiaomi app. It's the most useful manual control tool for underwater photography on this type of device: it visually indicates which elements of the image are in focus, allowing you to lock the focus on a specific subject without relying on automatic AF.

In clear water, the omnidirectional PDAF is fast and reliable on subjects moving at moderate speeds. For fish that move quickly, the autofocus acquisition speed is decent but not exceptional. The absence of a laser AF avoids the common problem with hybrid AF systems in murky water - this neutrality results in predictable behavior.

Specs B6 - Underwater Autofocus

Autofocus Technologies: Omnidirectional PDAF (main sensor). PDAF on other sensors. LiDAR: Absent. Laser AF: Absent (no risk of drift due to suspended particles). Focus Peaking: Available in the Xiaomi Pro app mode. AF/AE Lock: Available (long press on the subject). AI Scene Detection: Present via HyperOS 3.

Score B6: 3.5/5

The 15T does not have a dedicated housing listed on the first page of the Divevolk website at the time of testing. The universal model that is suitable here is the Divevolk SeaTouch 4 Max (not Platinum), with an internal adapter specifically for the 15T.

The SeaTouch 4 Max is certified to 60 meters and features a functional touchscreen underwater (SeaTouch gel technology). It provides full access to camera apps from inside the housing - including Pro mode for Xiaomi cameras, MotionCam Pro, and Blackmagic Camera. To order the adapter specific to the 15T model, you must contact Divevolk directly before your first dive, as the exact dimensions of the phone determine the internal fit.

For use in light snorkeling or freediving, flexible universal housings (such as Seafrogs or Kraken) can be suitable for depths up to 20-30 meters, but they offer less comfortable touchscreen operation and have a certified depth rating that is lower.

Specs B7 - Housing

Main option: Divevolk SeaTouch 4 Max with a universal adapter specifically for the 15T. Material: aluminum. Certified depth: 60 m. Underwater touchscreen: yes (SeaTouch gel, functional up to 40 m). App access: complete (Xiaomi Pro mode, MotionCam Pro, Blackmagic Camera). Alternative option: Universal soft housings from Seafrogs/Kraken for snorkeling or freediving. Price of SeaTouch 4 Max: ~299 USD (housing only, check with the dedicated adapter).

Score B7: 3.8/5

Available enclosures

The primary option for the 15T is the Divevolk SeaTouch 4 Max with a dedicated universal adapter. Direct contact with Divevolk is recommended before purchase to confirm the availability of the 15T adapter and the mounting dimensions.

Flexible alternatives (like Seafrogs H16) are available for use in shallow water (snorkeling, freediving) at a lower cost, but they are not suitable for autonomous diving beyond 20 meters.

The field workflow

For a day of 3 dives shooting in RAW format with the 15T camera:

• 250 photos x 30 MB DNG = 7.5 GB per dive
• Total for the day: approximately 22 GB
• 256 GB capacity: covers 10 days without intermediate transfers
• Backup transfer via USB 2.0 OTG: 22 GB in ~12 minutes

For 4K 60fps Log video recording, a daily data transfer is mandatory for the 256GB version. The USB 2.0 speed (~35 MB/s) requires planning: connect the OTG SSD in the evening and start the transfer before dinner.

Current prices (June 2026)

New: - Xiaomi 15T 256 GB: ~395 EUR (Amazon.fr, Fnac) - source idealo.fr / lesmobiles.com, June 2026 - Xiaomi 15T 512 GB: ~479 EUR (Fnac) - source fnac.com, June 2026

Refurbished (Back Market) deals: - Xiaomi 15T 256 GB, good condition: ~280-320 EUR (estimated based on Back Market price ranges for comparable models, June 2026 - check backmarket.fr/fr-fr/p/xiaomi-15t) - Note: Since the 15T was released in September 2025, refurbished units are relatively new. Prices for used devices will likely decrease in the coming months with the release of the 17T.

To compare with: - New Xiaomi 15 Ultra: ~€1,100-€1,200 - New Xiaomi 15T Pro: ~€650-€700

The price point of the 15T makes sense: a well-rated refurbished device for under €300, combined with the SeaTouch 4 Max speaker at $299 USD, creates a complete system for under €600. This is the most compelling positioning for this phone in terms of underwater photography.

Key Considerations

USB 2.0 and video: If the primary use is 4K video with a large amount of footage, the 15T imposes a significant workflow constraint. A 15T Pro (USB 3.2 Gen 2) or a 15 Ultra would then be justified based on this criterion alone.

Lithium-ion batteries in cold water: For regular dives below 12 degrees Celsius (Atlantic Ocean, English Channel, Brittany), plan for a day with an extra battery or a recharge between dives.

Housing and adapter: Always order and test the adapter before your dive trip. Divevolk prints the adapters in 3D according to the exact dimensions of the model - do not assume compatibility without written confirmation.

For a comparison with other available smartphones, see the underwater smartphone camera comparison for 2026.

The Xiaomi 15T is an honest phone for taking photos, as long as you don't expect it to do things it wasn't designed for.

The Leica's RAW capabilities are excellent, the colorimetry is well-calibrated, the plastic chassis limits condensation better than many metal flagship phones, and the 5500 mAh battery lasts a standard day. For a diver who goes diving two or three times a year in tropical waters and takes a moderate number of photos, this system works well.

The limitations come from the USB 2.0 port for those who film a lot, and from the Li-ion battery for regular use in cold water. These are not hidden flaws - they are documented in the manufacturer's specifications. The 15T does not claim to be an Ultra.

The strongest argument for the 15T is its price. A refurbished unit in good condition costs around €280-300, and combined with the Divevolk SeaTouch 4 Max, it forms a complete and capable underwater system for less than €600. This is a realistic option for an Android photographer who is exploring underwater photography using natural light and doesn't want to invest in an Ultra camera right away.

For a more in-depth comparison between the two models, see the complete review of the Xiaomi 15 Ultra.

Final score: 3.4/5

Are you hesitant? Use our underwater photography equipment comparison tool to compare this camera with other tested models.

To learn more about condensation and overheating, read our dedicated article: Overheating and condensation on a smartphone in an underwater housing.