Viltrox says it’s preparing a firmware update to smooth out compatibility issues some photographers are seeing between its autofocus lenses and Sony’s new a7 V — and the company doesn’t believe Sony deliberately changed anything to sabotage third-party glass.
In comments shared with PetaPixel, Frank Fang, Viltrox’s US marketing director, said the company’s R&D team is actively testing and expects to ship an update before the end of the week of December 15, 2025, aimed at improving stability and consistency across real-world shooting conditions.
What Viltrox says is happening
According to Fang, the problem looks less like a “Sony blocked third-party lenses” scenario and more like the messy reality of camera–lens communication across a fast-moving ecosystem.
Viltrox points to “edge cases” where different body firmware versions, lens firmware versions, and usage scenarios can surface performance inconsistencies — the sort of thing that can show up right after a major new camera launch, even if the same lenses behaved normally on earlier models.
The planned firmware update, Viltrox says, is designed to fine-tune parameters and improve overall reliability rather than introduce new features.
How the “Sony is bricking lenses” rumor took off
The speculation started gaining traction during the a7 V review cycle, after YouTuber Kai Wong reported autofocus issues with multiple Chinese-made third-party lenses.
Wong framed it as something to watch closely, noting it could be an early firmware issue — but the clip also fed into a familiar internet storyline: a big platform owner quietly tightening control, leaving third-party accessory makers and customers in the cold.
Sony’s response didn’t exactly calm anyone down
Sony has been notably restrained in public comments about third-party lens behavior on the a7 V. In the statement PetaPixel reported receiving, a Sony representative said photographers should contact each lens maker for details about third-party lens performance.
That response — effectively, “talk to the lens company” — didn’t confirm or deny anything technical. But it did leave a vacuum that online speculation was happy to fill.
Is this something Sony can fix?
Viltrox’s position is straightforward: it has not seen evidence of intentional behavior on the camera side.
That doesn’t mean camera firmware never plays a role in compatibility quirks — it can — but in many cases, the most practical fix lands with the lens manufacturer through firmware updates that better align communication timing, error handling, or performance tuning with a new camera body’s behavior.
In other words: if a new camera reveals fragile assumptions in a lens’ firmware, the lens maker often has to harden those assumptions.
Sony has previously framed E-mount as an ecosystem play
The irony is that Sony has spent years positioning E-mount as a creator-friendly ecosystem — in no small part because third-party lenses make it stronger.
Earlier in 2025, Sony executive Masanori Kishi, Senior General Manager of Lens Technology and Systems Business Unit, described third-party competition as a positive pressure on Sony’s own lens development and emphasized the breadth of the E-mount ecosystem.
That public posture doesn’t prove anything about the a7 V’s technical behavior — but it’s a key reason many photographers were skeptical of the “Sony suddenly closed the mount” narrative as it spread.
What to expect next
Viltrox expects its a7 V-focused firmware update to roll out imminently (again, before the end of the week of Dec. 15, 2025). If the root cause is the kind of post-launch edge-case tuning Viltrox suggests, other lens makers could follow with their own updates as they validate performance across more bodies and more shooting conditions.
For a7 V owners, the practical takeaway is simple: if you’re seeing autofocus oddities or inconsistent behavior on third-party lenses, keep an eye on firmware releases from your lens manufacturer — and don’t assume the camera itself is “blocking” anything without hard evidence.