Originally posted by rx2man I was going to get the Pentax made adaptor, read not to buy a aftermarket version, its all metal, so I will be good to go then.
Well, not really. None of the narrow-flange M42-PK adapters will cover the pins. It doesn't matter if they're Official Pentax or 3rd-party -- they just aren't wide enough. The adapters I spoke of would be the safe cheap wide-flange NIF (no-infinity-focus) adapters, or those on macro tube sets, or on bellows, or the 'universal' T-mount (or T2 or TX) or Adaptall type, or mount-reversal adapters. I stick a bit of metal tape on the base of my M42 lenses before adding a narrow-flange adapter.
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Now,
my M42-PK adapter spiel: Everyone with just a very few screwmount lenses should own *ONE* Official Pentax adapter, the shiny-metal narrow-flange sort that costs so much. Mount it in the camera, (un)screw lenses in it. Safe and tedious.
Those of us with many screwmount lenses own many cheap clone (3rd-party) adapters that look like the Official Pentax but have the notorious screw-and-clip. REMOVE THE SCREW AND CLIP OR YOU WILL GO APESH!T! Then use a rear lens-cap to wrench the adapter onto the lens. I've had some adapters on for so long that I've almost forgotten the lens isn't Pentax-native. Haven't lost one yet!
There's a third type of adapter, the cheap safe wide-flange NIF sort. These are useful with some long tele lenses that focus past infinity anyway, and with lenses meant for closeup or macro use, or for portrait use where infinity doesn't matter.
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For your first screwmount lens, get an Official Pentax adapter. For subsequent lenses, think about the other sorts. They are immensely useful; I have dozens. And you're certainly welcome for the help. That's what I'm here for.