Nikon vs. Viltrox – Chinese Patent Office Declares Nikon’s Z-Mount Patent Invalid

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by Nino LeitnerAugust 3^rd, 2026

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China’s patent office has declared one of Nikon’s Z-mount-related patents entirely invalid, handing lens maker Viltrox a significant win in the legal dispute between the two companies. Nikon can still appeal the ruling in court, but for now, a key patent in its case against the Shenzhen-based manufacturer is off the table in China.

Viltrox has grown from a maker of lens mount adapters into one of the most prolific third-party lens manufacturers in the industry, and Nikon Z-mount autofocus lenses are a substantial part of its catalog. We have covered the company’s rapid expansion extensively here on CineD, from its E-Z AF lens mount adapter for Nikon Z cameras to its entry into the L-Mount Alliance and the growing anamorphic and autofocus ecosystem we looked at during NAB 2026. That expansion has now collided head-on with Nikon’s intellectual property strategy, and the first major decision in the resulting dispute has gone Viltrox’s way.

What the decision says

The ruling comes from the China National Intellectual Property Administration (CNIPA) and is dated July 13, 2026. We have seen the full decision document, and its conclusion is unambiguous: Nikon’s patent, granted in 2021 and simply titled “Accessories”, is declared invalid in its entirety because its design lacks an inventive step.

The patent describes the core geometry of a lens mounting to a camera body: the arrangement of the four bayonet lugs, the angles between them, and the placement of the electrical contacts. According to Nikon, this design prevents incorrect mounting, protects the contacts, and improves impact resistance. It is worth stressing, however, that this is one specific patent, not blanket protection for the entire Z-mount system.

How Viltrox took the patent down

Viltrox challenged the patent at CNIPA in December 2025, arguing that Nikon’s design was nothing an engineer in the field could not have come up with. As evidence, the company submitted three earlier patent documents from the US, China, and Japan describing similar bayonet mounts, terminals, and anti-misinsertion features.

Nikon defended the patent and even narrowed its claims along the way, but it was not enough. The panel found that the differences between Nikon’s design and the earlier documents were either already suggested there, belonged to common knowledge in the lens mount field, or amounted to obvious design choices, such as using four bayonet lugs instead of three. On that basis, the patent was invalidated in full.

The wider dispute, and what remains unconfirmed

The invalidation did not happen in a vacuum. Nikon reportedly initiated infringement proceedings against Viltrox in China earlier this year, and the invalidation request is widely understood as Viltrox’s countermove, a standard defensive strategy in Chinese patent disputes, since an invalid patent cannot support an infringement claim. We want to be transparent about the sourcing here: the details of that infringement case rest on reports rather than published court records, and at the time of writing, neither Nikon nor Viltrox has issued an official statement. What is documented first-hand is the invalidation decision itself.

The ruling is also not necessarily final. Nikon has three months to challenge it before the Beijing Intellectual Property Court, and it applies only to this one patent and only within China. Nikon holds many other patents connected to the Z system, and the decision says nothing about electronic communication protocols, autofocus operation, or any market outside China.

Business as usual for Viltrox

Throughout the proceedings, Viltrox has continued to release Nikon Z-mount products at its familiar pace, most recently the AF 26mm f/2.8 EVO full-frame pancake lens for Sony E and Nikon Z. The company’s engineering ambitions clearly reach beyond mirrorless primes, too: we recently put its NexusFocus F1 through its paces in our full review, an adapter that brings autofocus to manual PL cinema lenses by tapping directly into Sony’s phase-detection system. More on the company’s lineup can be found on the Viltrox website.

Beyond this specific case, the ruling touches a question that concerns every filmmaker who relies on third-party glass: how much control camera manufacturers can exercise over their lens mounts. Approaches vary widely across the industry. Sony discloses the basic E-mount specifications to partner companies that pass its review process and publishes an official list of its license partners, which currently includes names such as ZEISS, Cooke, SIGMA, Tamron, Samyang, and Cosina. Notably, Viltrox does not appear on that list either. Canon, by contrast, kept a historically tight grip on the RF mount that only recently loosened for selected licensed SIGMA lenses, while Nikon has not published a comparable partner list or an open Z-mount specification.

Let us be clear about where we stand: in our view, lens makers should license a mount before building products for it. A mount is not just a bayonet; it is an engineering platform that camera manufacturers develop and maintain at considerable cost, and a license is what ties a third-party lens to that platform contractually, with guaranteed compatibility across firmware updates instead of reverse-engineered protocols that can break at any time. Sony’s partner program shows that licensing and a thriving third-party ecosystem are not opposites; if anything, it is the model the industry should converge on. This ruling may have weakened one of Nikon’s patents in China, but it does not change that reality for filmmakers: a licensed lens is a safer long-term investment than an unlicensed one, however capable and affordable the latter may be. The healthiest outcome of this dispute would not be a free-for-all, but Nikon and Viltrox finding their way to a licensing agreement.

Do you shoot third-party lenses on Nikon Z cameras, and should manufacturers open their mounts to licensed partners? Don’t hesitate to let us know in the comments below!