Review on K&F Concept M42 to Sony E Mount Lens Adapter Ring for a6000 a6300 a6500 a5000 a5100 a3500 a3000 Alpha A7 A7R a7S a7II a7RII a7SII a7III a7RIII and a9 by April Smith

First, the mount on my Sony and my Nikon lens attached to the mount with no problems. The first problem is that the camera won't let you use autofocus because the lens is "loose". The second problem is that the corners of the image are dark, as if edited as a vignette. I used my Nikon 55-300 and at maximum zoom the corners were even darker. I then used my Nikon 35mm prime lens and it still had dark corners. Conclusion: Don't look for a cheap way and don't buy a third-party mount. Pay more and enjoy your money.