The Sony RX100 series revolutionized compact camera performance when the original model debuted in June 2012. It made a significant impact on the underwater photography community by offering an exceptional combination of a large sensor and a highly portable body. The camera delivered excellent video quality, supported TTL in manual mode, and was compatible with a wide range of wide-angle lenses, such as the UWL-04 fisheye lens, making it a favorite among underwater photography enthusiasts.
In 2013, the RX100 II was released, introducing a back-illuminated sensor, which claimed to enhance image quality. However, field testing revealed only marginal improvements in underwater photography conditions, leading many to see it as more of an incremental update than a significant leap forward.
Less than a year later, Sony unveiled the RX100 III. This third-generation model brought several key updates, such as an electronic viewfinder and a brighter lens with a 24-70mm focal range at f/1.8-2.8. While these changes offered potential benefits in certain contexts, they also introduced trade-offs, especially for those focused on macro and wide-angle underwater photography.
The Legacy and Impact of the Original Sony RX100
When the original Sony RX100 hit the market, it broke new ground. Compact yet powerful, it housed a 1-inch sensor, a remarkable achievement for a camera of its size. This sensor size contributed significantly to improved low-light performance, dynamic range, and depth of field control—qualities especially valuable underwater where lighting conditions can be challenging.
It quickly gained popularity among divers due to its compatibility with underwater housings and accessories. TTL flash functionality in manual mode allowed users to achieve well-exposed images with minimal effort. Additionally, the camera’s responsiveness and quick autofocus made it suitable for capturing fast-moving subjects, such as fish and small marine creatures.
Compatibility with popular wide-angle lenses enabled photographers to push creative boundaries. The RX100 worked seamlessly with wet lenses, allowing users to switch from macro to wide-angle during a single dive. It was precisely this versatility that helped it become a go-to compact camera for underwater use.
Understanding the Evolution from RX100 II to RX100 III
The RX100 II was released with expectations for major enhancements. Although the back-illuminated sensor suggested improvements in noise performance and low-light shooting, the difference was subtle, especially underwater. Photographers often found that the real-world benefits were negligible when shooting in aquatic environments, where water clarity and lighting dominate image outcomes more than slight sensor changes.
The RX100 III brought more noticeable hardware upgrades. Most significantly, it introduced a completely new lens—a 24-70mm f/1.8-2.8 lens—replacing the 28-100mm lens found on earlier models. This change improved the brightness at the telephoto end, which was helpful for indoor or low-light shooting on land. However, for underwater shooters who favored the longer reach for macro photography, this trade-off reduced magnification potential and working distance.
The inclusion of an electronic viewfinder was a notable development for land photography, aiding visibility in bright environments. Yet, for underwater photography, where most housings do not support viewfinder access, this feature added cost without practical benefit.
Evaluating Lens Changes and Their Underwater Implications
One of the most debated changes in the RX100 III is the replacement of the original lens with a wider but shorter 24-70mm lens. From a terrestrial photography standpoint, this upgrade provides a brighter aperture and a broader field of view at the wide end. However, for underwater applications, the shorter reach presents several challenges.
In macro photography, a longer focal length translates to more magnification and greater working distance. This is especially useful when photographing shy or skittish subjects such as gobies or jawfish. With the 28-100mm lens, photographers could zoom in without disturbing the subject. The 24-70mm lens limits that ability, requiring photographers to get physically closer, which can spook marine life or introduce more backscatter from stirred-up sediment.
Similarly, wide-angle wet lenses perform differently depending on the base focal length. In most cases, 28mm offers better corner sharpness and less distortion with wet lenses than 24mm. During pool testing with the UWL-04 fisheye lens, results confirmed that 28mm performs more consistently across the frame, especially in underwater scenarios where peripheral sharpness is essential.
Strengths of the Sony RX100 III for Underwater Photography
Despite its drawbacks, the RX100 III brings several features that enhance its performance in underwater settings. The upgraded bit-rate for video, jumping from 28Mbps to 50Mbps with the XAVC format, allows for cleaner, sharper footage with less compression artifacting. This is particularly beneficial for capturing detailed marine scenes or for those interested in color grading footage in post-production.
The camera also features a new high-speed recording mode, enabling slow-motion playback by capturing at 120 frames per second. This feature opens creative possibilities for documenting fast marine movements, like a squid jetting away or a nudibranch gliding across coral.
Another upgrade is the built-in three-stop neutral density (ND) filter. This allows photographers to shoot at slower shutter speeds even in bright conditions, making it easier to capture motion blur or smooth out water movement for artistic underwater shots.
Focus performance is excellent, with fast and accurate autofocus that exceeds the capabilities of many compact competitors. This ensures fewer missed shots and better subject tracking, critical for dynamic underwater environments. Combined with the large sensor, this speed results in high-quality, professional-grade photos and video.
Limitations and Considerations for Underwater Use
Though it offers improved features, the RX100 III introduces a few limitations. First, it is slightly larger and heavier than its predecessors. While still compact, this change makes it less pocketable and more noticeable when diving with it mounted in a housing. The difference may seem minor, but could affect travel and dive gear considerations, especially for those prioritizing minimal setups.
Second, the shorter focal length lens reduces macro capability. With the original RX100, users could capture a subject as small as three inches across. With the RX100 III, the smallest frame width increases to about 1.78 inches when using macro wet lenses. Though still respectable, this lower magnification and working distance make it harder to achieve the same level of detail and background separation.
Finally, the shorter lens limits reach for photographing shy subjects. Marine creatures often retreat when approached too closely. The ability to zoom to 100mm or beyond allows photographers to keep their distance while still filling the frame. The 70mm limit of the RX100 III may require cropping images or repositioning, potentially resulting in missed shots or compromised compositions.
Overview of Underwater Housing Options
The RX100 III enjoys strong support from major housing manufacturers. Options from Ikelite, Recsea, and Nauticam are all available, catering to different budgets and feature requirements. These housings provide reliable access to essential controls and allow the use of wet lenses for macro or wide-angle photography.
Each brand offers unique strengths. Nauticam housings are known for their ergonomic design, robust build quality, and support for vacuum systems. Recsea offers compact and lightweight housings, while Ikelite provides more affordable solutions with transparent bodies for visual feedback. All these housings ensure the RX100 III remains a strong contender for underwater shooting, provided its limitations are well understood and matched with appropriate gear.
Real-World Underwater Performance and Lens Behavior
The Sony RX100 III performs impressively underwater when paired with quality housings and lighting setups. The 1-inch sensor continues to be a strong performer, producing sharp and detailed images with vibrant color reproduction. The dynamic range is sufficient for capturing a wide variety of underwater scenes, from brightly lit coral reefs to dimly lit caves and wrecks.
In good visibility, the camera renders fine textures and gradients in marine life with exceptional clarity. However, performance can drop slightly in murky conditions or at depth, particularly when natural light fades. The lens handles chromatic aberration and vignetting well, although edge sharpness can vary depending on the wet lens attached and the zoom setting used.
Wide-Angle Shooting Considerations
The 24mm wide-angle setting on the RX100 III lens allows you to capture broad reef scenes and large subjects like turtles or sharks. However, the 24mm focal length doesn’t always pair as cleanly with some wide-angle wet lenses. Tests show that wet lenses originally optimized for 28mm perform with some corner softness or distortion at 24mm.
For best results, slight zooming in—around 28 to 35mm—can improve corner performance with many wet lenses. This may lead to a narrower field of view but can significantly enhance sharpness and overall image quality. Pairing the RX100 III with fisheye converters like the UWL-04 or UWL-09 can still produce compelling results, but composition may need to be adjusted to account for lens behavior.
Macro Shooting Limitations
Macro photography is where the RX100 III shows some regression compared to its predecessors. The 24-70mm lens lacks the longer reach of the 28-100mm lens, reducing maximum magnification. This becomes more noticeable when photographing tiny creatures such as nudibranchs, shrimp, or pygmy seahorses.
With a wet macro lens like the Bluewater +7, you can still achieve good close-ups, but you will have to get closer to the subject. This introduces the risk of scaring off animals or disturbing sediment, leading to backscatter. Additionally, working at closer distances makes lighting more difficult, as strobes or lights must be positioned carefully to avoid creating shadows or overexposing the subject.
Although post-processing and cropping can compensate for some limitations, they also reduce image resolution. Underwater macro shooters may find more value in cameras with longer native focal lengths or interchangeable lens systems, though those typically come with greater bulk and expense.
Autofocus and Shutter Response
Autofocus on the RX100 III is fast and accurate, significantly better than older compact models. This makes it easier to lock focus on fast-swimming fish or moving subjects like turtles or cuttlefish. In macro situations, the autofocus remains confident in locking onto textures and patterns, although it can occasionally struggle in low contrast or very close-range scenes.
Shutter lag is minimal, and the camera responds quickly when pressing the shutter button. This is particularly helpful in unpredictable underwater scenarios where subjects may move quickly. The RX100 III is especially effective when paired with a reliable strobe setup, helping to freeze motion and enhance detail.
Underwater White Balance and Custom Settings
Manual white balance adjustment is important for capturing true colors underwater. The RX100 III offers good manual control, allowing custom white balance settings that help offset the strong blues and greens present underwater. For ambient light shots, adjusting the white balance is essential for natural-looking results.
The camera also allows for multiple custom shooting modes, making it easier for divers to switch between macro and wide-angle configurations quickly. Save one setting for macro with spot focus and higher aperture, and another for wide-angle with center-weighted metering and a wider field of view.
These user-defined modes significantly streamline operation underwater, where quick adjustments can be difficult. The menu system, although dense, becomes manageable with familiarity, and essential settings are easily accessible via the function button.
Accessories, Housings, and Customization for Underwater Use
There are several reliable housing options for the RX100 III, each catering to different budgets and user preferences. Major brands like Nauticam, Ikelite, and Recsea have created housings with unique advantages. All of these offer depth ratings suitable for recreational and most technical dives, generally ranging from 130 to 200 feet.
Nauticam housings are highly regarded for their rugged design, ergonomic layout, and optional vacuum sealing systems. These housings offer precise control over the camera and excellent support for accessories such as macro diopters, wide-angle wet lenses, and strobe arms.
Recsea housings are compact and lightweight, making them ideal for travel. They offer good control access and are often constructed from anodized aluminum for durability. Their smaller size makes them an excellent match for divers who want a streamlined setup.
Ikelite provides the most affordable option, usually built from polycarbonate materials. While bulkier, they offer transparent housings, which allow the user to see the camera and internal components. Ikelite’s housings also support TTL strobe operation with compatible flashes, making them a good choice for those who prioritize lighting performance over aesthetics.
Lighting and Strobe Compatibility
The RX100 III works well with external lighting, and underwater photographers will benefit greatly from strobes or continuous video lights. The built-in flash can trigger optical strobes effectively through fiber-optic cables. Most housings support fiber-optic connections for strobes like the Sea & Sea YS-D3 or the Inon Z330, both of which offer powerful lighting and TTL support.
For video, pairing the RX100 III with high-output continuous lights such as the Kraken Hydra or BigBlue series can dramatically improve footage quality. These lights help illuminate reef scenes or wide-angle subjects, reducing the need to boost ISO, which can introduce noise.
The RX100 III allows manual control of flash output, and this flexibility is critical when fine-tuning strobe balance or avoiding overexposed highlights. With the ability to shoot in manual mode, users can match their lighting precisely to the conditions and subject distance.
Filters and Wet Lenses
Color correction filters can be attached to the housing port or lens adapter to enhance ambient light photography. These filters help restore reds and yellows lost at depth. However, they are only suitable for shallow water and natural light shooting, and they reduce light reaching the sensor, making them less ideal for deep dives or low-light environments.
Wet lenses are essential for unlocking the RX100 III’s full underwater potential. Wide-angle wet lenses expand the field of view and allow the user to get closer to large subjects, thereby reducing water between the lens and subject and improving clarity. Macro wet lenses increase magnification and are critical for shooting the smallest critters.
The RX100 III’s compatibility with most wet lenses remains strong, though the new 24mm wide end may not work as cleanly as the 28mm did on older models. Photographers may need to test combinations or stick with known compatible wet lenses like the UCL-165, Subsee +10, or Nauticam CMC series for macro.
Recommended Shooting Modes and Tips
For best results underwater, manual mode is recommended. Set the aperture between f/5.6 to f/8 for sharpness, especially when using wide-angle wet lenses. Shutter speed should be set to at least 1/125 for most scenes, faster if photographing fast-moving fish or using ambient light. Keep ISO as low as possible to maintain image quality.
Use spot focus and center-weighted metering for macro photography, and switch to multi-area focus and evaluative metering for wide-angle reefscapes. Burst mode can be helpful when photographing moving subjects or for capturing the perfect moment of fish behavior.
Finally, always review images during your safety stop or after the dive to identify improvements in composition or settings for the next dive. The RX100 III’s high-resolution LCD screen offers good feedback, even when viewed through a housing.
Post-Processing, Image Management, and Long-Term Value
Image and Video Post-Processing Benefits
The Sony RX100 III produces JPEG and RAW files that offer plenty of flexibility in post-production. For photographers who shoot in RAW, adjustments to exposure, white balance, highlights, and shadows can be made without degrading image quality. This is particularly useful underwater, where lighting conditions and water color often vary throughout a dive.
RAW files from the RX100 III retain rich detail and color information. Blues and greens can be softened or enhanced, and reds lost at depth can be restored. When shooting macro, detail sharpening and clarity adjustments bring out fine textures in subjects like nudibranchs and coral polyps.
For video editing, the XAVC codec provides high-bitrate footage that holds up well under color correction. White balance shifts, saturation boosts, and sharpness adjustments can be applied with minimal loss in detail. This makes the RX100 III suitable not only for casual underwater video capture but also for documentary-style projects or social media reels.
Software such as Lightroom, Capture One, or Photoshop works seamlessly with RX100 III files. Video editors like DaVinci Resolve and Adobe Premiere Pro can handle the XAVC format efficiently, allowing for smooth workflow even when combining underwater clips with topside footage.
Battery Life and Storage Considerations
Battery life on the RX100 III is moderate and can be a limiting factor for extended dive trips. Underwater photography, especially with frequent use of the screen, flash, and autofocus, drains the battery quickly. On average, one battery lasts through one to two dives depending on shooting habits.
Carrying extra batteries is essential. Most underwater housings offer battery access only after a full breakdown and drying period, so pre-charged spares should be on hand before heading out. Using airplane mode and reducing LCD brightness can help conserve power, but it’s best not to rely on these methods alone.
Memory card capacity is another factor to consider. Shooting RAW and high-bitrate video requires fast and large-capacity SD cards. Class 10 or UHS-I cards with at least 64GB of storage are recommended. Always carry backups in case of card failure or if you are shooting multiple dives in a day without time to offload footage.
Durability and Maintenance in Marine Conditions
Compact cameras like the RX100 III are not inherently waterproof and rely on housings for underwater operation. Maintenance of the housing is critical to prevent leaks or equipment failure. After every dive, the housing should be rinsed thoroughly in freshwater and left to soak if possible. Special attention should be given to O-rings, which must be cleaned, lubricated, and inspected before each dive.
The RX100 III itself is well-built and durable when treated with care. Its metal body resists minor scratches and bumps. However, saltwater exposure—even in small amounts—can cause corrosion or button failure over time. Ensure the camera stays dry between dives and keep desiccant inside the housing to prevent fogging.
Divers who use the camera frequently over several years report that the RX100 III maintains consistent image quality and autofocus performance. With proper care, it proves to be a reliable companion for both beginner and intermediate underwater photographers.
Upgrading or Staying with the RX100 III
Choosing whether to stay with the RX100 III or upgrade depends on individual needs. If video is a top priority, newer models such as the RX100 IV or RX100 V offer better slow-motion capabilities, faster frame rates, and improved autofocus tracking. For still photography, however, the RX100 III holds its ground, delivering high-resolution, well-balanced images that meet the needs of most underwater users.
Some photographers may prefer moving to an interchangeable lens system for more creative flexibility and superior macro or wide-angle results. However, these systems are more expensive, bulkier, and require more time and expertise to operate underwater.
If your goal is portability, ease of use, and solid performance across a range of conditions, the RX100 III remains a strong and cost-effective choice even years after its release. Its lens limitations can be mitigated with the right accessories and techniques, while its strengths in autofocus, image quality, and responsiveness continue to deliver consistent results.
Conclusion: Is the Sony RX100 III a Smart Investment for Underwater Photography?
The Sony RX100 III is a compact powerhouse that delivers exceptional image and video quality in a small, travel-friendly body. It brings several meaningful improvements over its predecessors, including a brighter lens, electronic viewfinder, better video codec, and fast autofocus performance. These features contribute to a camera that performs well in both land and underwater environments.
For underwater photography, the RX100 III excels in versatility and image quality, though it introduces trade-offs. The reduced zoom range impacts macro magnification and reach, while the 24mm wide end may not pair as cleanly with some wide-angle wet lenses. Despite these compromises, with the right combination of lighting, lens accessories, and housings, the RX100 III can still capture striking underwater imagery.
Its autofocus speed and burst shooting abilities are assets when photographing active marine life. The camera handles challenging underwater lighting with confidence, especially when used with external strobes or video lights. Manual settings allow creative control and consistent exposure, and the XAVC video codec delivers strong results for aspiring videographers.
While newer models and systems offer technical advancements, the RX100 III holds its value by offering a balanced combination of performance, build quality, and portability. It remains one of the best options for divers who want high-quality results without stepping up to bulky mirrorless or DSLR rigs.
In the ever-evolving world of underwater photography, the Sony RX100 III continues to be a relevant and capable tool—especially for those who understand its strengths and work around its limitations. For travel, casual diving, and even more serious image-making, it is a compact camera that punches well above its size.