Sony List of Official E-Mount Partners Has Some Interesting Exclusions

Sony has published a list of what it calls E-Mount License Partners, where the basic specifications of the mirrorless mount have been disclosed to companies “which satisfy the qualification criteria predefined by Sony.”

The E-mount is considered to be “open,” insofar as Sony does not prevent manufacturers from making lenses for its mirrorless cameras. Sony executives have told PetaPixel that the company believes lenses from third-party manufacturers benefit visual creators overall thanks in part to Sony’s collaboration with some other companies. Sony has said that “competition is high, but it’s good competition” and that it believes the openness of E-mount is a “strong point” for the Alpha system.

All of that said, this is the first time the company has made any notice of E-mount “License Partners,” indicating there is some kind of tier system in place: companies that work directly with Sony and companies that do not.

The list includes expected brands like Cooke, Zeiss, Tamron, and Sigma as well as Kenko Tokina, Cosina, and LK Samyang. Some inclusions that might surprise are Fujifilm and Thales. The latter manufactures fringe optics under the Angenieux brand, while many may not have known that Fujifilm does make Fujinon cinema lenses for E-mount (although they are rare and special-order only).

It is PetaPixel‘s understanding that these official partners have a greater level of access to Sony engineers and camera data, as opposed to relying fully on reverse engineering. That brings up the notable exclusions from this list: Chinese lens makers like Viltrox, Venus Optics, 7Artisans, or TTArtisan.

This does add some further clarity to a situation from last year when some content creators reported issues with the a7 V and Viltrox lenses. At the time, PetaPixel did not believe this was some kind of nefarious decision by Sony, and that ended up being confirmed both by Sony and by Viltrox. Viltrox later released a firmware update that fixed compatibility issues with the high-resolution camera.

PetaPixel is not aware of any costs associated with becoming an official E-mount licensing partner, and outside of some stipulations (like administrative costs) that a brand would need to cover, there doesn’t appear to be any particular reason brands like Viltrox could not seek official partnership with Sony. Clearly it is not required, but it is entirely possible Viltrox never asked. That’s not an entirely unreasonable assumption given its recent spat with Nikon.

Interestingly, even an official partnership with Sony does not guarantee compatibility.

“The E-mount Basic Specifications are disclosed for compatibility. It does not guarantee the compatibility or quality of all functions. For quality assurance, please contact the license partner,” Sony says.

So, at this time, it appears the only benefit is direct access to E-mount specification data, although there could be more to the license than is publicly known. PetaPixel has reached out to Sony for details on what exactly the benefits of being an official license partner are. Should the company provide that information, this story will be updated.

It should be noted that at this time, PetaPixel has not seen the “qualification criteria” that Sony references. It’s not clear if this has been made publicly available, but that has been requested as well.

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Image creditsSony