Alex Mustard's Field Review: The Sony A7R VI Underwater

In this article adapted from The Underwater Photography Show, I (Alex) share my first impressions of the Sony A7R VI after shooting it in the Red Sea.

I went out to run back-to-back underwater photography workshops in Egypt, and my new housing caught up with me halfway through the trip — which was perhaps a blessing in disguise. It meant I shot the first week with my A1 in a given set of conditions, then switched straight into the A7R VI for the second week, giving me a really direct, comparative sense of how the two cameras stack up. The Red Sea gave me a great range of photography to test it on: high ISO work, wide angle of big animals and big scenes, close-focus wide angle, wrecks, reefs, schools of fish, split levels, and a good dose of fish photography and macro.

Before I moved to Sony mirrorless, I always ran two housings, rarely diving with both at once but keeping the redundancy of a macro rig and a wide angle rig available on the boat. That was my original motivation for buying this camera — I wanted a second Sony mirrorless setup, not necessarily a replacement for my A1. But the headline from this trip is that the A7R VI is now going to be my main camera, and I don't have any second thoughts about that.

I did run into a couple of niggles worth flagging. The first was flash sync speed. I couldn't get the full 1/250th sync using the flash triggers I had on hand — an Underwater Technics trigger not designed for this camera worked to 1/250th, but understandably wasn't trustworthy, failing to fire on the first shot after the camera woke from sleep. With both manual Nauticam and Underwater Light & Magic triggers, I'd get a slight unflashed (in macro, black) band right at the top of the frame at 1/250th, about as wide as the blue border at the top of the screen on the show. In a horizontal wide angle reef scenic without flash-lit subject matter, you would often get away with it, but it was a frustration. I'm hoping to get a specific Underwater Technics made Nauticam board for this camera soon, which should resolve it. Interestingly, the band was very slightly thinner when I used my Backscatter HF-1s versus my Retra Pro Max 2s, but present with both sets of strobes. I only used the HF-1s twice, though, as I definitely prefer the look of light in my pictures from the Pro Max 2s.

My second niggle was the color on the EVF. On land I preferred the A7R VI's viewfinder to my A1's straight away — same 9 million pixel resolution, but sharper and crisper. Underwater, though, the first few dives left me unconvinced by the colors, something I would probably not have noticed if I hadn't switched cameras mid-trip. Readers should note that I'm notoriously fussy about color. Amusingly, I had almost the opposite experience to what most underwater photographers report: usually your photos look great on the camera underwater and disappointing once downloaded. For me it was the reverse — I'd come out of the water a bit disappointed, then download the files and be very happy! Once I got used to the viewfinder, I stopped noticing it.

White balance is definitely an improvement with this camera. I usually don't like Sony Auto white balance shooting underwater with flash, but I happily used this extensively when shooting macro. The Auto white balance gave excellent, consistent results — genuinely the best I've seen on a Sony. I look forward to testing it more. Underwater Auto white balance was also very impressive for available light shooting, or for those shots that are mostly available light with just a touch of flash. For most of my wide angle, though I used a fixed Kelvin white balance (4800 K with my Retras, 4200 K when I add my FCP).

The new battery in this camera bulks up the grip, but also bulks up battery life. The new battery (combined with the power-saving dimming EVF) gives a big improvement in battery life. I found one long dive — 80 mins, 250 images — would leave 80% battery remaining, suggesting 4 (safely) or 5 dives per charge, whereas if the dives were deeper, shorter, and with fewer images because of deco limits (such as on the Thistlegorm), I would have 80% remaining after two dives, which suggests possibly 10 dives per battery charge. Anyway, I would suspect for most people the battery will last a day of diving. And the new charger is nicer than the old one too, and the % charge is reported much more accurately — all of which are positives.

The autofocus is where this camera really impressed me. I've always felt the A1 was fast and the A7R V was smart — this camera is smarter and faster than both. Subject detection is excellent: it has no trouble tracking fish or picking out eyes on macro subjects, and I almost never turned subject detection off when shooting macro because it worked so reliably, and just puts a box straight onto the eye. Compared to its predecessor, the A7R VI feels like a step on again in the same way the A7R V was a step on from the A7R IV — the EVF, the autofocus, and the ISO performance have all improved further. There are revolutions under the skin, but in terms of user experience it feels like evolution — the same philosophy of camera, made better.

For me, the predecessor A7R V's weak points are high ISO performance and multiple frame shooting, and both are resoundingly answered with the new camera. This camera continues to perform excellently as you push ISO up, and for high ISO work it actually outperforms my A1, which is remarkable. The resolution bump itself isn't hugely significant to me, but the files are enormous — nearly 10,000 pixels in the long dimension — with sharp details and excellent dynamic range. There can't be any better image quality currently in full frame.

It can also shoot electronic-shutter bursts up to 30 frames per second, blackout-free, though that's not something we typically use in flash photography underwater since many flash triggers won't fire with electronic shutter engaged. Still, for action shooters it's valuable, provided you've got the hard drive space to handle the data. Blackout-free shooting is one of those features you don't think you need, as it feels so natural when you use it — and then you go back to a camera without it, and you really notice the difference.

Overall, I've always found something to moan about with my A1's color, and I really like the color out of these files. I'd like more time and more trips with it to firm up all my conclusions, but I'm genuinely thrilled with both the low ISO image quality (ISO 400 and below) and the high ISO performance. My one wish is an even lower ISO setting — it still bottoms out at 50, and as an underwater photographer shooting open-aperture macro in bright conditions like the Red Sea, a true low ISO boost setting would be really valuable.

One of my favorite things about this camera is how easily its programmable Shooting Modes are accessible through the menu, all set under the star button. Think of them a little like bookmarks, so you can pick up where you left off when you switch to a different branch of photography. I've created modes for wide angle, macro, available light (which switches white balance and turns off auto-review since there's no flash to check), black and white (same idea — EVF goes monochrome, no auto-review needed), an action mode (wide angle with auto-review off so the screen isn't reviewing in my face mid-action), blackwater (a macro variant tuned with slightly higher ISO and more depth of field, plus low-level rapid shooting), split-level, topside wildlife, and a wide angle mode specifically for my FCP port (with white balance shifted about 700 Kelvin lower to counter its slightly yellow glass). Switching between wide angle and macro setups between dives now takes about three seconds. There are ten slots on the menu plus two more accessible via the mode dial, though I don't love using the dial on the housing since you can't see where you've turned it to — I generally prefer leaving the mode dial on * and navigating the visual menu instead.

I shot the camera in Nauticam's new housing. The big change on the housing side is the new port lock mechanism, which has been showing up across a lot of newer housings. The locking mechanism is redesigned to be more robust and also lets you simply push the port on and it locks — it just clicks into place. You still need to undo the latch to remove it, but it's a nice quality-of-life improvement.

On my A1 housing, the vacuum valve sits in a particular spot, and this housing has that area repurposed with a threaded hole for screwing in a monitor ball mount, rather than needing to remove the vacuum fitting to access it — probably a nod to how popular external monitors have become.

One important compatibility note: I heard from Byron that one of his guests in the Red Sea tried fitting an A7R VI into an A7R V housing, and it didn't fit properly — the camera is just slightly bigger through the grip area. I'd be cautious about assuming it will fit other housings just because it's close, but not the same, in size. Also, if you have an A7R V and you get an A7R VI, the latter will be the only camera you'll want to shoot — and using it in a housing that's slightly compromised doesn't seem like a good plan going forward. I didn't try to see if the A7R V fits in the larger A7R VI housing, but I would expect it does, and that would be a better bet if you want a backup camera body.

If you're a potential Sony owner, this is your obvious purchase right now. If you're an existing Sony shooter on anything older than an A1 Mark I, this is a clear full-frame upgrade, if you want one. If you're currently on an A1 or A7R V, this camera is a significant upgrade over both — though I wouldn't call it a must-have. Think of it a bit like a new iPhone release: yes, it's better, and yes there'll be an even better one in 2–3 years' time. And so on. You don't need every upgrade. That said, if your current housing has good resale value, or your camera feels like it's getting long in the tooth, you would be very happy with this swap. If you're shooting an A1 II or A9 III, autofocus performance is more comparable to what you already have — maybe not image quality, but given the size of that recent investment, I don't think this camera makes sense as a next purchase for you right now.

Is it revolutionary? Under the skin, yes. But as a user, no. It is Sony bringing all its good stuff together in one place, with a new stacked sensor and processor driving faster, smarter autofocus and higher frame rates, great high ISO, blackout-free shooting, and even more resolution and dynamic range. It's a lovely, balanced product, and every time I tried something different with it, it excelled. That's why it's becoming my main camera, with the A1 moving into backup duty.

All that said, one week wasn't enough to get to know such a capable camera, and Matt and I plan to revisit the A7R VI later after the summer once we've both had more time shooting it on both warm and cold water trips. If you'd like to watch the full conversation, you can find it here.