The UV filter does not change the thread or the thread size. The thread is identical again on the UV filter above. 

Good morning, two days before Christmas Eve, so first of all I wish you a Merry Christmas and a peaceful start to the New Year 2021, which may bring you the best of health and great contentment. And now to the question about the Olympus connection. I find it strange that Amazon is forwarding this question to a user of CANON EOS full-frame cameras. I have very little knowledge of other camera connections. All I know is that you are in good hands with Olympus, they are all high-performance precision mechanical and optical devices. The question of the compatibility of the K&F Concept lens with Olympus can only be answered by Olympus or Foto-Walser as the importer and sales partner of K&F Concept. However, based on decades of photo experience, I can imagine that there can be no adapter option from Canon EOS to Olympus bayonet. The connections are fundamentally different with their electronic transfers from the lens to the camera and in the number of copies. I haven't checked whether this lens even has an Olympus mount. A suitable Olympus connector would be perfect though. Just ask Olympus or Foto-Walser. Incidentally, Amazon is showing the wrong lens here, I don't have a manual 14 K&F Concept, but the AF version, and it works great with EOS. I wish you the best of luck with your research. One more thing, I'm not bothering to make a video answer as I just wanted to answer your question and not a free promotion for the lens. And the text is enough for that. Have fun and success with the Olympus products. 

I think the low vignetting comes from the lens hood. The filter itself does not. 

Hi, this variable nd filter supports no vignetting range is 24mm. If the lens out of this range (such as 14）,there would be a little vignetting on images. 

こんにちは。組み合わせに適したアダプターを見つけるには、レンズのレンズ マウントと接続するカメラのボディ マウントを知る必要があります。したがって、M42 マウントのレンズをお持ちの場合は、このアダプターを使用して Canon EF および EF-S カメラに取り付けることができます。