Jim Chung reviewed the Yongnuo YN455 Micro Four Thirds Camera and concluded:
In addition to a terrible AF system, the camera fails to satisfy the standards of the m43 lens mount. M43 manual focus lens like the Laowa 7mm f/2, 43rds lens using the MMF-1 adaptor and EOS lenses using a Metabones adaptor do not function at all on this body. The error message displayed reads: “The lens is not ready. Please unscrew the lens to the proper position.” Which is beyond cryptic.
And also in violation of the standards of the m43 lens mount, when a new lens is changed, the aperture does not default to the largest aperture of the new lens but maintains the last selected aperture.
It is hard to imagine the decisions that lead to spending millions of dollars to tool up and fabricate this camera when its market and audience is so unclear. It’s not a camera for smartphone users because the thing is a brick. It literally has the dimensions of a clay brick used in domestic residential construction with even a small to medium sized lens attached. And it’s not for the serious photographer or dedicated m43 user because the poor AF system means that it cannot take full advantage of its interchangeable lens ability – the ability to use quality high focal length optics that will always be beyond the capabilities of smartphone based cameras. Even the Yi M1 is a better camera. A much better camera. You can see my review from several years ago https://jimchungblog.com/2017/02/03/a-real-world-performance-review-of-the-yi-m1-camera/