Originally posted by wings Thanks Steve, I was not aware of that. However, I did discover that I had to screw the adapter in (tighten) slightly before I was able to release the leaf lock. I didn't have problems after that, but perhaps I will remove it anyway.
LeRay
Google "stuck M42 adapter" for lots of sad stories. When it happened to me, it took multiple attempts over a three hour period to free my Bower-brand adapter from the camera. I was on the verge of resorting to the Dremel tool.
With the spring lock, gone the lens is free to rotate out of the mount. This may be a problem if the focus ring is stiff. I hate to say it, but a common solution is to notch or drill the face of the lens to accept the K-mount retention pin.
Steve