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The author would like to thank Canon Australia and Nauticam for providing a Canon EOS R5 Mark II, lenses, housing, and ports, and Scubapix for providing a flash trigger, for the purposes of this review.
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The very first time a camera was lent to me, it was my mother’s Canon Prisma (sold as the AF35 in the US, Autoboy in Japan). I was eight, and it was still the film era, and while I enjoyed snapping a few images, I only caught the photography bug much later in life. At 22, the engineering student in me was fascinated by the rapid progress of digital photography and eager to buy my first DSLR—naturally, a Canon. I started saving for a pro-level EOS 1D Mark III, but the cost of the body, let alone an underwater housing, was a challenge. Then something happened that fast-tracked my jump into underwater photography: Nikon released the D300. It was more affordable, had the specs I dreamed of, and was compatible with cheaper housings. It was 2007 and I’ve been shooting Nikon ever since, aside from a two-year side trip with Olympus (now OM System).
Fast-forward to 2025: While reviewing Backscatter’s TTL flash trigger, I had the chance to use the Sony Alpha 1 extensively for two months. Switching back to my Nikon Z9, I was curious about how Canon’s latest mirrorless bodies would fare underwater. As an underwater educator and coach—I run an underwater photography school and community called The Underwater Club—it’s important I stay familiar with different systems, so I can advise students and mentees. My time with the Nikon Z9 and Sony Alpha 1 also taught me that each flagship camera has strengths and quirks that don’t always show up in reviews—so it was time to form my own view on Canon’s latest offering.
That opportunity came in May, thanks to Canon Australia and Nauticam, who loaned me the R5 Mark II, lenses, housing, and ports, with further support from Scubapix (Nauticam Australia) for an additional flash trigger. This review, based on firmware 1.03, draws on over 60 hours of diving in temperate and tropical waters, day and night, and in visibilities from 10 to 100 feet.
The author, ready to dive the Canon EOS R5 Mark II in the Australian winter
1. The Canon EOS R5 Mark II
The R5 Mark II was announced in July 2024 alongside Canon’s flagship R1. I’ll focus on the features that matter most underwater or strike me as noteworthy; autofocus performance, viewfinder experience, battery life, and video shooting have dedicated sections further down.
The R5 Mark II’s 45-megapixel sensor offers generous cropping flexibility, valuable for super macro and for shy wide-angle subjects. This higher resolution is also why I chose the R5 Mark II over the 24-megapixel R1 for my first Canon review. Maximum flash sync is 1/250s in “Electronic 1st Curtain” mode, which uses a mix of mechanical and electronic shutter. The camera also offers full mechanical and full electronic shutter modes, each with trade-offs:
| Shutter Mode | Mechanical | Electronic 1st Curtain | Electronic (ES) |
|---|---|---|---|
| Max sync speed | 1/200s | 1/250s | 1/160s |
| Maximum burst speed | 12fps | 12fps | 30fps |
| Dynamic range | Maximum | Maximum | Slightly reduced* |
| Vibrations | Both curtains | Reduced (2nd curtain only) |
Minimal |
*Testing by PhotonsToPhotos measured ~0.5 stops less dynamic range in Electronic ES compared to mechanical shutter, and ~0.4 stops less than the original R5
For underwater use, I recommend “Electronic 1st Curtain” unless you’re shooting only ambient light or need more than 12fps. It’s worth noting that the R5 Mark II records 14-bit RAW files in all shutter modes.
In recent years, progress in sensor technology has been more about read speed (supporting autofocus functions, reducing rolling shutter, etc.) than pure image quality, so I didn’t expect much of a surprise from the R5 Mark II sensor. Still, I am fully satisfied with the camera’s performance in this regard: Images hold impressive detail even after heavy cropping or when bumping the ISO past the 2,000 mark. As a bonus, I really like Canon’s color rendering for underwater scenes. Overall, the R5 Mark II’s image quality was what I expected from a modern 45-megapixel full-frame sensor—which is to say excellent.
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Top: a grossly overexposed photo (see the histogram). Bottom: the same photo with exposure dialled down. I am satisfied with highlights recovery on overexposed images, even when further from base ISO (Canon EOS R5 Mark II, Nauticam housing, Canon RF 100mm f/2.8L Macro, Nauticam SMC-3, single Retra Flash Pro Max II, f/16, 1/200s, ISO 500)
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I wouldn’t hesitate to bump up the ISO to 3200 if conditions called for it. Here, it was necessary to freeze the fast movements of this Australian sea lion, photographed in Baird Bay (South Australia). Top: full image. Bottom: 100% crop (Canon EOS R5 Mark II, Nauticam housing, Canon RF 24–50mm f/4.5–6.3 at 47mm, Nauticam FCP-1, ambient light, f/11, 1/500s, ISO 2500)
Like my Nikon Z9, the Canon EOS R5 Mark II has a built-in sensor shield—a simple feature I greatly appreciate, especially on remote trips where I wouldn’t want to attempt a sensor clean.
In terms of camera ergonomics, I liked the dedicated photo/video lever and the ability to assign one individual dial each to shutter speed, aperture, and ISO. Coming from Nikon, Canon’s control layout took a while to get used to (Sony’s was closer), especially navigating between photos while reviewing them.
I found Canon’s approach to lens controls a little restrictive: Whenever a lens has physical switches (AF/MF, IS), those functions are disabled in the camera menus. Thus, with the camera locked inside a housing, there wasn’t an easy way to toggle off autofocus. My workaround was assigning a custom shooting mode to back-button focus (I normally focus with the shutter button), but with only three custom modes available, I would have preferred to reserve those for other uses.
On the positive side, Canon allows extensive button customisation—I’ve counted nine controls that could be used as shortcuts/different functions. Still, I wish the “rate” and “zoom” buttons were customisable, too, as I actually ran out of options when tailoring the camera to my needs.
On that note, it took about half a day to go through all the R5 Mark II’s menus and configure them to my liking, and further tweaks followed as I kept diving. I strongly recommend spending time optimizing your R5 Mark II (or any advanced mirrorless cameras for that matter) to fit your preferences for underwater use. If you want to save time, I’ve shared my own setup in a blog post on The Underwater Club.
In the following dedicated sections, I’ll cover autofocus performance, viewfinder experience, battery life, and video shooting.
High-speed bursts are great to capture fast-paced action such as these bottlenose dolphins at Baird Bay, South Australia (Canon EOS R5 Mark II, Nauticam housing, Canon EF 8–15mm f/4 Fisheye, Nauticam 8.5" acrylic dome, ambient light, f/8, 1/800s, ISO 1600)
2. Autofocus Performance
While image quality hasn’t progressed much since the last DSLRs, autofocus is where mirrorless cameras have truly moved the needle. Underwater, we find no shortage of erratically moving wildlife, and we photographers are often moving, too, due to surge and current. This makes continuous autofocus tracking (or AF Servo, as Canon puts it) a very important feature for me. I am pleased to say the R5 Mark II has one of the most efficient autofocus systems I’ve used underwater.
With 1,053 focus points covering the entirety of the frame (90% of the frame has user-selectable focus points), the R5 Mark II can track subjects smoothly all across the image. The autofocus is competent in low ambient light, too (rated by Canon to –6.5 EV), and I rarely felt the need to use my focus light—advantageous for approaching marine life.
I found autofocus tracking (AF Servo) to be very accurate. For this portrait, I shot my macro lens fully open and relied on continuous tracking as I got closer to this sergeant baker, a skittish fish that may flee at any moment (Canon EOS R5 Mark II, Nauticam housing, Canon RF 100mm f/2.8L Macro, dual Backscatter Hybrid Flash, f/2.8, 1/250s, ISO 100)
Super macro is when I’d normally switch on a focus light to help the camera deal with extra-thin depth of field. Whilst pygmy pipehorses don’t seem bothered by focus lights (at lower power), this one studiously avoided my snoots’ aiming lights, so I turned them off. To my surprise, the R5 Mark II still did a decent job of tracking the eye, after I prefocused near it (Canon EOS R5 Mark II, Nauticam housing, Canon RF 100mm f/2.8L Macro, Nauticam SMC-3, dual Retra Flash Pro Max II with dual Retra LSD, f/22, 1/200s, ISO 800)
Subject detection technology really is where I see the innovation frontier in terms of camera autofocus. Canon has been praised for the R5 Mark II’s range of detection capabilities, which can even be tuned to “understand” different sports, but what does it make of fish and cephalopods? These fit in the generic “animals” detection mode, and I found it worked surprisingly well with a range of marine species, especially those with birdlike eyes—which includes a lot of fish life.
Underwater photography is a niche specialty and there is—so far—no camera manufacturer that offers a dedicated “underwater” detection mode, but it felt like the R5 Mark II piggybacked on all the AI training it has received on birds, which is all to our benefit! It occasionally got confused “identifying” the wrong subject, so I set a shortcut to toggle detection off.
Cute, inquisitive, and erratic—three traits of the eastern blue groper, whose eye was automatically detected and tracked by the R5 Mark II with impressive consistency (Canon EOS R5 Mark II, Nauticam housing, Canon RF 24–50mm f/4.5–6.3 at 33mm, Nauticam FCP-1, dual Retra Flash Pro, f/11, 1/50s, ISO 500)
Like other mirrorless cameras, the R5 Mark II can get distracted by backlit particles between subject and lens, which is when I would revert to one-shot AF or manual focus. DSLRs were less prone to this, though not as capable at tracking fast or erratic movement.
A welcome surprise was how the Canon focused under a red light, which is my preferred way of approaching subjects at night; most marine animals don’t mind a red dive light compared to a white one. Every mirrorless camera I have used until now has really struggled with focusing under such lighting, whereas it was a non-issue with my DSLRs. This likely has to do with radically different AF systems being used: DSLRs have a dedicated autofocus sensor, whereas mirrorless cameras rely on the image sensor. The R5 Mark II is the first mirrorless camera I’ve used that performed acceptably under red light—not as fast as DSLRs, but definitely usable. Canon’s Dual Pixel AF II deserves credit here.
After setting up my lighting, I approached this juvenile serpent eel under a red light and let the autofocus do its job (Canon EOS R5 Mark II, Nauticam housing, Canon RF 100mm f/2.8L Macro, single Retra Flash Pro Max II with Retra LSD, f/18, 1/200s, ISO 200)
With the Nauticam EMWL attached, the R5 Mark II not only focused fast under a red light, it also managed to detect and track subjects, likely helped by the Nauticam optic reinforcing underwater contrast. This estuary catfish’s eye was reliably detected and tracked while it was foraging for food and stirring up the sand (Canon EOS R5 Mark II, Nauticam housing, Canon RF 100mm f/2.8L Macro, Nauticam EMWL, single Backscatter Mini Flash 2, f/18, 1/250s, ISO 640)
Finally, a quick word on Canon’s Eye Control AF—an innovative feature that automatically focuses where you look in the viewfinder. Sadly, it relies on your eye being close to the camera’s eyepiece, so it doesn’t work underwater, as your eye sits too far away, separated by the housing viewfinder and dive mask.
3. Viewfinder Experience
Despite the advantages they offer, electronic viewfinders (EVFs) are sometimes considered a weak point of mirrorless cameras, as they can lose detail in highlights and shadows, feel laggy when there’s fast action, and produce noisy images in low-light conditions. However, the compromises are less pronounced than ever, and overall, recent cameras are delivering a more comfortable and productive underwater viewing experience.
The R5 Mark II’s 5.76M-dot EVF isn’t class-leading (some reach 9.44M dots), but it’s more than adequate for me. I’ve happily shot with 3.69M-dot EVFs before and didn’t feel I needed more. The R5 Mark II’s EVF can refresh at 120Hz, though I used the 60Hz power-saving mode to extend battery life, and I found the view to be fluid enough.
For me, being able to adjust the EVF’s color balance (so I don’t struggle to find that goby, sitting still on a rubble patch) is more important than resolution and refresh rate. Unlike an optical viewfinder—where your brain compensates for the blue-green cast—an EVF relies on configuration to correct its display colors. Here, the R5 Mark II excels: A straightforward “Screen/viewfinder color tone” option shows you four versions of the last photo, so you can pick the one that feels most balanced from a color standpoint. There’s another menu option to further refine your EVF’s white balancing (“Fine-tune VF color tone”). I assigned both to “My Menu” for quick access. (Read how I customized the R5 Mark II for underwater photography here.)
The only limitation I noticed was in extreme contrast scenes, such as aiming from beneath a ledge toward the surface, where shadow and highlight detail can’t be shown simultaneously. This is a common EVF limitation, but it never prevented me from finding subjects or composing effectively.
When framing my photo through this cave, I could see everything through the EVF, except for the blue water behind the diver, which looked overexposed. That is a typical limitation of EVFs, but it didn’t matter, as I could clearly see my subject contrasting against the background, and the marine life growing on the cave’s ceiling (which was all dark till my strobes flashed) (Canon EOS R5 Mark II, Nauticam housing, Canon EF 8–15mm f/4 Fisheye, Nauticam 140mm glass dome, dual Retra Flash Pro Max II, f/11, 1/30s, ISO 640)
On the bright side—excuse the pun!—EVFs shine in the dark: They brighten the scene without a torch, making subjects easier to spot. EVFs also allow instant review without moving your eye from the viewfinder—great for checking strobe exposure. And for those shooting continuous light only, an EVF gives a real-time preview of both exposure and lighting.
During night dives, I also appreciated how quickly the EVF adapted to sudden brightness changes, such as a focus light being turned on or off. I’ve seen some EVFs being “blinded” and taking a second or two to adjust.
Overall, the R5 Mark II’s EVF is very well suited to underwater photography, and personally, I wouldn’t trade it for the best DSLR optical viewfinder.
4. Battery Life
In the DSLR days, battery life was measured in number shots per charge. With mirrorless cameras, even though CIPA battery testing still quotes number of shots, a more relevant metric is how long a camera can remain awake/active. Just looking through the EVF uses power, focusing adds more, and filming drains it fastest.
For underwater shooters, the key question is how many dives you can cover before having to open the housing. I often spend over three hours on rebreather dives, so a camera lasting 2h45 instead of 2h30 means I can extend a dive. However, this small difference wouldn’t matter much if you’re on a trip doing 60-minute consecutive dives—you would still be changing batteries every two dives. The big question is: Can the R5 Mark II last for three standard 60-minute dives?
In my experience, the R5 Mark II usually lasted past the three-hour mark. Here are a few dive log examples, illustrating how much battery consumption varied with usage:
| Dive Log Example | Battery Life |
|---|---|
| 3h20 wide angle, 408 photos, 3x 4K/30p clips | 25% remaining |
| 3h05 wide angle, 700 photos, lots of autofocusing in the dark (cavern) | 10% remaining |
| 3h40 macro, 754 photos, 30× 4K/120p clips | empty at 3h20 |
| 2h40 low-vis wide angle, 455 photos, 6× 4K/30p clips | 5% remaining |
| 65min macro, 185 photos | 70% remaining |
| 3h10 macro, 450 photos, heavy AF use (super macro) | 10% remaining |
| 2h30 macro night, 233 photos, 200s 4K/30p video | 34% remaining |
| 1h40 macro night, 138 photos | 64% remaining |
Two caveats:
- I used Canon’s LP-E6P battery. Older LP-E6NHs died in under 90 minutes.
- I optimized settings for power, e.g., reducing EVF refresh to 60Hz. (My complete settings here.)
With these settings and using the new LP-E6P battery, the R5 Mark II comfortably handles two busy dives with stills and video, and may well last for three 60-minute dives, depending how busy they are. If I were on a macro trip, a private guide constantly showing me subjects to shoot, I’d play safe and would still change batteries every two dives.
In summary, the R5 Mark II delivers the best battery life I’ve seen in a mirrorless camera that doesn’t have an integrated vertical grip.
5. Lens Choices
Macro Lenses
The best macro partner for the R5 Mark II is the Canon RF 100mm f/2.8L IS USM. Released in 2021, it replaces the classic Canon EF 100mm f/2.8L IS USM (2009). The RF 100mm f/2.8L is unique among 90/100/105mm full-frame macros lenses in achieving 1.4x magnification natively (others stop at 1.0x), and its aperture stops down to f/32—which is great for super macro.
The lens also features a spherical aberration control ring, which softens images and alters bokeh. I didn’t try it underwater, but Nauticam makes the SA Control Ring to access this feature while in a housing.
I do wish Canon would release a shorter RF macro lens (around 60mm) for larger fish portraits, low-visibility dives, or blackwater. Until then, the Nauticam MFO-3 can be used with the RF 100mm to shorten working distance and mimic a 60mm field of view.
The Sydney pygmy pipehorse’s head is less than half an inch long, and such a high reproduction ratio (uncropped) would have required a diopter with other full-frame macro lenses (Canon EOS R5 Mark II, Nauticam housing, Canon RF 100mm f/2.8L Macro, dual Retra Flash Pro Max II, f/18, 1/200s, ISO 800)
Sydney pygmy pipehorses also come in white! The RF 100mm works well with wet diopters like Nauticam’s SMC-3, extending its magnification from 1.4x to 2.3x. At such a short working distance, closing down the aperture to f/29 helped get a little more depth of field for both eyes to be sharp (Canon EOS R5 Mark II, Nauticam housing, Canon RF 100mm f/2.8L Macro, Nauticam SMC-3, dual Retra Flash Pro Max II, f/29, 1/200s, ISO 1600)
The RF 100mm f/2.8L Macro would occasionally hunt for focus, which can be helped by pre-focusing near the subject, but this was impractical here, as this red wide-bodied pipefish was rocking in the surge. I solved the problem by using the R5 Mark II’s focus register/recall function: One button memorizes the focus distance, and another tells the camera to return to that saved distance, which is handy when the subject is “lost.” Both these functions now have shortcuts in my custom settings (Canon EOS R5 Mark II, Nauticam housing, Canon RF 100mm f/2.8L Macro, Nauticam SMC-3, dual Retra Flash Pro Max II, f/29, 1/200s, ISO 640)
Wide-Angle Lenses
Every keen wide-angle shooter should own a fisheye, the lens that produces the most eye-catching perspectives in underwater images. Canon’s EF 8–15mm f/4L USM works beautifully with the R5 Mark II via the EF-RF mount adapter, though the lens is now discontinued. A few retailers still have brand-new stock, and it’s not difficult to find second hand, but I hope Canon will release a modern RF fisheye. My ideal? A compact 15mm f/2.8 that focuses right on the glass and stops down to f/22 for over-unders.
In the darkness of this cave, the R5 Mark II struggled to lock onto the shark till I turned on my focus light. I know it’s a tough ask, but if my bare eyes can see the subject, I’d love my camera to be able to do the same! I wonder if a faster RF fisheye would have done the trick? (Canon EOS R5 Mark II, Nauticam housing, Canon EF 8–15mm f/4 Fisheye, Nauticam 140mm glass dome, dual Retra Flash Pro Max II, f/11, 1/50s, ISO 1250)
There’s no shortage of ultra-wide, rectilinear lenses for the RF mount (diagonal field-of-view in parentheses):
- RF 10–20mm f/4 IS USM (130–94°)
- RF 14–35mm f/4L IS USM (114–63°)
- RF 15–30mm f/4.5-6.3 IS STM (110–71°)
- RF 15–35mm f/2.8L IS USM (110–63°)
I didn’t have access to any of these lenses during this review, but they are all suitable for underwater photography, provided you use a large dome port (180–250mm in diameter).
A noteworthy alternative to a wide-angle lens and dome is Canon's affordable RF 24–50mm f/4.5–6.3 IS STM lens paired with Nauticam water-contact optics. The WWL-C covers the 130–72° range while being compact, travel-friendly, and still able to resolve as much detail as a fisheye (see sharpness comparison in my Nikon Z8 review). I also used the 24–50mm with the Nauticam Fisheye Conversion Port (FCP-1), which expands the field-of-view to 170–87°. The FCP-1 is heavier and more expensive but offers impressive versatility.
This critically endangered white-spotted guitarfish was an unexpected encounter in the waters of Australia’s largest city! I was lucky to have the Nauticam FCP-1 with me on that dive, so I could zoom further out and get closer to this rare ray (Canon EOS R5 Mark II, Nauticam housing, Canon RF 24–50mm f/4.5–6.3 at 28mm, Nauticam FCP-1, dual Retra Flash Pro Max II, f/13, 1/60s, ISO 500)
6. Flash Triggering
For any underwater photographer that uses strobes—that’s most of us—maximum flash sync speed is a very important spec. When shot in “Electronic 1st Curtain” mode, the R5 Mark II achieves a respectable flash sync speed of 1/250s.
Not all flash triggers can reach that speed though. The Nauticam TTL Flash Trigger for Canon syncs at 1/250s but can’t go beyond ~3fps when shooting bursts. The Nauticam Manual Flash Trigger for Canon handles high-speed bursts but only syncs to 1/200s—black bars appear at 1/250s.
One limitation with Canon is that you can’t select front- or rear-curtain sync unless the trigger is recognized as a Speedlite. At normal shutter speeds this is irrelevant, but at 1/20s or slower, having that option lets you control the appearance of motion blur for creative purposes.
The Nauticam TTL trigger is recognized as a Speedlite and unlocks sync options, letting me control if I want the flash to fire at the beginning or at the end of my long exposure. Here, since I am panning the camera, it needs to be at the beginning (Canon EOS R5 Mark II, Nauticam housing, Canon RF 100mm f/2.8L Macro, dual Retra Flash Pro Max II, f/20, 1s, ISO 100)
I’m curious to try additional Canon-compatible triggers. Ideally I’d like one that:
- unlocks Speedlite controls (front/rear curtain sync),
- supports the R5 Mark II’s 1/250s sync limit,
- sustains at least 12fps bursts (the R5 Mark II’s maximum speed in “Electronic 1st Curtain” mode), and
- includes a battery indicator—unless the trigger can last for 10,000s of shots.
Bonus features would be TTL and stroboscopic modes. If any flash trigger manufacturer is reading this, you’ve got my wish list!
7. Video Shooting
I should preface this section by saying I’m primarily a stills shooter. I record video occasionally—for clients, or when there’s an interesting behavior and I’ve already secured all the stills that I could want. So my use of the R5 Mark II’s video features is not that of a full-time videographer, and I haven’t tried every mode. That said, the specs are impressive. The R5 Mark II records uncropped 8K/60p in Canon’s RAW Light format, with 10-bit depth at 60p and 12-bit at 30p.
I shot mostly in 4K. At 30p, the footage is oversampled from 8K for improved detail and lower noise. Subsampling is used for faster frame rates, but without cropping the sensor. I primarily used 4K/30p and 4K/120p (recorded at 30p for slow motion), but the camera also supports Full HD at 240p, slowing down the action eightfold.
A video reel mixing sequences filmed in Baird Bay (South Australia) and in Sydney (New South Wales). The lens used is mentioned at the beginning of each sequence
I enjoyed filming with the R5 Mark II and captured many keeper sequences, even though I only shot video opportunistically between stills, with no tripod, and relying on the autofocus. I was impressed by the R5 Mark II’s smooth tracking of sea lions and dolphins (beginning of the reel), and found the continuous autofocus surprisingly usable for macro (with the RF 100mm). As expected, it became more hit and miss when I added a diopter for super-macro sequences.
Wide-angle clips were shot with ambient light only, making white balance critical. Canon is well regarded for acquiring custom white balance at depth, and it did indeed work well, but the process was quite cumbersome: Take a photo in stills mode, switch to video, open the menus, select the reference photo, if need be zoom on the target, confirm. I’d prefer a configurable shortcut, whereby I could to point the camera at a slate, sand patch, or tank, and grab a reference on the spot by pulling the shutter.
It’s worth noting that the original R5 was known for overheating when shooting demanding video. The R5 Mark II is designed to manage heat better, but I didn’t stress-test it, as I shot neither 8K nor extra-long sequences. Videographers planning on shooting continuous 8K or oversampled 4K should note that Nauticam offers a housing-mounted cooling fan, in case heating issues arise.
8. The Nauticam Housing
The NA-R5II is the ninth Nauticam housing I’ve dived with, and once again I’m really impressed by the ergonomics. Nauticam consistently lays out controls in ways that make the housing intuitive and efficient. My top five usability highlights:
- Exposure controls: Three separate wheels give direct access to shutter speed, aperture, and ISO—always at your fingertips.
- Joystick: Canon’s tiny 8mm multi-controller is mapped to a generous 30mm joystick, making AF point selection and menu navigation far easier, even with thick gloves. It also has a central push button for a quick zoom when checking sharpness.
- EVF/LCD lever: A mechanical switch blocks the eye sensor and lets you toggle between EVF and LCD, saving me from dedicating a shortcut to this essential functionality.
- Levers galore: No fewer than seven levers are laid out on the sides of the housing. These are my favorite type of housing control, as they’re easy to operate without letting go of the handles.
- Buoyancy: The housing is slightly positive, meaning I needed fewer floats to offset strobes and diopters.
Like all of Nauticam’s housings, the NA-R5II is a joy to use
Inside, the housing may look complex, with gears and linkages rerouting controls, but in practice I’ve found Nauticam products to be extremely reliable. Despite heavy use—including bumping on rocks and week-long trips without a freshwater rinse (not recommended, but sometimes unavoidable)—I’ve never had to send one in for service, despite over 500 hours of diving on some housings.
Nauticam has been refining its housings for 15 years, and the NA-R5II immediately felt familiar: oversized dials usable with gloves, the excellent joystick, and the vacuum system I trust. I wasn’t expecting any surprises, but two stood out: a discreet slot for an Apple AirTag under the camera tray—great peace of mind for travel—and a dedicated ON/OFF button for the optional cooling fan (see Video section), a thoughtful touch for videographers.
The housing open, with both shells side by side
I used the Nauticam 40° angled viewfinder for the entirety of this review, providing a comfortable view of the R5 Mark II’s large EVF, even when shooting low on the sand
9. Final Thoughts
In the DSLR era, cameras like Nikon’s D500 and D850 gave me everything I needed underwater. But in 2025, after extensive time with high-end mirrorless bodies from Nikon, Sony, and now Canon, I’ve come to rely on features DSLRs can’t match: subject detection, near-full-frame AF coverage, seamless stills/video switching, and EVFs that offer instant review. Whenever I grab a DSLRs for a dive, I love the battery life, but I quickly miss those advantages.
After 10 weeks with the Canon R5 Mark II in varied conditions, I’ve grown to love using this camera: It shines in areas that matter to me, such as red-light autofocusing and better battery life. Like the Nikon Z9/Z8 and Sony Alpha 1, it has quirks—but different ones.
The positive takeaway is that Canon, Nikon, and Sony now all make mirrorless cameras that are excellent underwater tools. They provide a more productive experience than DSLRs, with only a few lingering limitations (batteries still fall short of a full day of diving, and AF can be tricked by backlit particles). For a deeper discussion on how these three brands compare, register for The Underwater Club’s October webinar, where I’ll be discussing the pros and cons of each, based on extended underwater use of these cameras.
In a nutshell, I have been very impressed by the Canon EOS R5 Mark II. It is the mirrorless camera that best suits my needs as an underwater photographer, and I loved shooting it in the Nauticam NA-R5II housing, so much so that when the loan ended, I chose to buy them—and I plan to keep using this capable combo for the foreseeable future.
A stack of gray nurse sharks photographed during my May workshop in South West Rocks. We’re back there in October 2026! (Canon EOS R5 Mark II, Nauticam housing, Canon RF 24–50mm f/4.5–6.3 at 28mm, Nauticam FCP-1, dual Retra Flash Pro, f/11, 1/60s, ISO 500)
About the Reviewer: Nicolas Remy is an Australia-based pro shooter and founder of online underwater photography school and community, The Underwater Club, with members in 18 countries. He serves as an ambassador for Mares and Nauticam, and chairs the jury of the prestigious DPG Masters photo competition. Nicolas’ images have been widely published in print and digital media, and have won over 40 international photo awards. To see more of Nicolas’ work or browse his upcoming workshops, visit: www.nicolaslenaremy.com.
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