In just over a month, the Sony a7R VI has gone from having no available underwater housings to three options. Nauticam started the trend at the end of June, followed by Marelux at the end of July, and Aquatica has now completed the lineup. For the underwater photographer considering this camera body, the question is no longer whether an underwater housing exists, but rather which of the three best suits their needs.
The a7R VI, a quick recap.
The Sony a7R VI features a stacked Exmor RS sensor with 66.8 megapixels, supported by the Bionz XR2 processor. It can shoot up to 30 frames per second in electronic shutter mode without blackout, and video recording reaches 8K/30p (with a slight 1.2x crop) and 4K/120p at 10 bits with no cropping. The electronic viewfinder displays 9.44 million points. I had already detailed the specific benefits for underwater photography in the article about the NA-A7RVI: faster autofocus in murky water, a useful burst mode for pelagic creatures, and comfortable cropping margin at 66.8 megapixels.
What each container brings to the table.
Nauticam NA-A7RVI, priced at €4,200, emphasizes the longevity and breadth of its N100 ecosystem. If you already own N100 ports or housings from another brand, they can be directly transferred, a silent but decisive advantage for those already invested in the Nauticam system.
Marelux MX-A7RVI, priced at €2,950, focuses on offering a competitive price and the widest port available on the market, with a diameter of 125 mm, which is convenient for large macro lenses and wide-angle domes without extension rings. The optional manual flash trigger boasts 10,000 flashes using only two CR2032 batteries.
Aquatica A7R VI, priced at €3,700, stands out with a feature that neither Nauticam nor Marelux offers as standard on this housing: a 23.75 mm HDMI bulkhead opening for connecting an external monitor, and a choice of four flash connector configurations (none, Nikonos dual, Ikelite single, or optical dual with LED trigger). The Surveyor vacuum system (pump, valve, sensor) is included as standard, not as an optional extra.
The certified depth varies slightly: 100 meters for Nauticam and Marelux, 90 meters as standard for Aquatica (extendable to 130 meters with an optional reinforced spring kit). For the vast majority of recreational dives, this difference makes no practical difference. It only matters if you practice deep technical diving.
The real point of contention is the port system. None of the three are compatible with each other. Nauticam uses its N100 system, Marelux has its proprietary 125mm system, and Aquatica uses its bayonet mount system inherited from its DSLR housings. Therefore, switching brands means having to repurchase your entire set of ports and lenses, not just the housing itself. This factor is often what ultimately influences a photographer's decision, more so than any technical specifications.
If you're starting from scratch and budget is a priority, the Marelux at €2,950 opens the door to the a7R VI for €1,200 less than the Nauticam, without sacrificing the aluminum construction or the vacuum valve.
None of the three are bad choices. The a7R VI remains the same body in all three housings, with the same autofocus and burst shooting capabilities. What changes is the ecosystem you commit to for the following years, which is more important than underwater performance on the day of purchase.
