Originally posted by rdrum76 am I looking for the original asahi pentax M42 that supports full infinity manual focus??
thanks
The genuine Pentax mounts are a bit more expensive, but you get what you pay for. I also have a Kood, which looks like a direct copy, but cheaper.
The Pentax is designed to be inserted into the body, they have a spring that holds it firm. To remove the adapter you have to use a screw driver or something similarly small to push the spring so that you can turn the adapter. Clearly you have to do that without a lens in it
It is fiddly to do, so if you change lenses it is best to restrict yourself to M42 lenses, especially if you are outside on a shoot. Just to repeat: the Pentax adapter is designed to convert your camera into an M42 mount camera rather than convert your lens into a K mount.
The problem with the Kood is that the screw attaching the spring was sticking out, and so the adapter got stuck in my K100D
eventually I managed to persuade it to come out and the spring and screw just fell off, luckily they did not fall out inside the camera.
So if you have third party adapter make sure that you remove the spring before you use it. However, this means that it won't lock in the body mount. I have mine permanently screwed on to my Carl Zeiss Jena 135, so this means that the adapter has converted my lens into a K mount. There is one issue: M42 lenses do not have a hole for the body locking pin. The K mount on the body has some springs that grip the adapter bayonet lugs, but it is not enough to hold the adapter securely (this is why the Pentax adapter has the additional spring). As I focus my CZJ 135 towards close focus it has a tendency to turn the bayonet in the mount. I could fix this by drilling a hole in the lens for the locking pin, but with my experience with drills I would probably end up having two or three tries before I get the right place
One tip: you can get a PK end caps very cheap, and you should get some spares anyway. If you get the ones which attach to the lens with a turn (rather than the ones that just push on) it means it has stops in the end cap that matches the K bayonet and this is ideal to use to screw on or off an adapter (that has had the spring removed) on to a lens.
Richard