Samyang is a third-party lens manufacturer that is well known for creating affordable manual focus lenses, but over recent years it has been creating AF optics for most of the major camera mounts. However, it has issued an incompatibility notice between its AF lenses and the Sony A7C II, A7C R, A6700 and FX6, where they were unable to work with continuous AF.
In response, Samyang has issued a 'Beta Version firmware update notice'. It is not very often that camera or lens manufacturers release a beta version of a firmware update – I certainly haven't seen it before. In the official notice, Samyang states:
"Thank you to all of the Samyang lens customers.
We have been aware that there is a compatibility issue with some recently released Sony cameras and Samyang AF lenses. We are currently evaluating official firmware to resolve this issue, and releasing the Beta Version firmware files as follows, to minimize any inconvenience for customers may experience.
Compatibility Issue Camera Models
• A7C II (ILCE-7CM2)
• A7C R (ILCE-7CR)
• A 6700 (ILCE-6700)
• FX6 (ILME-FX6V)
Compatibility Issue Symptoms
•AF-C (Continuous AF) does not function properly"
Judging by the wording of the release, Samyang is unsure what has caused the incompatibility but is working on finding out – and is releasing a beta version to keep customers happy in the meantime.
The firmware also looks to be a tad complicated to update as there are many lenses and, depending on the type of lens, you have to update it a different way. However, there is a step-by-step photo guide on how to do it on Samyang's website, , once you figure out which firmware update suits your lens. Hopefully, this is an issue that can be fixed quickly!