I just got a Pentax SMC 85/2.2, and was looking forward to using it on my Pentax ME Super. Both are supposed to have K-Mounts according to the descriptions.

Unfortunately, I cannot mount the lens on my Pentax camera at all. The lens mount is a bit scratched, but this shouldn't be the reason it won't attach to the camera.

Why doesn't this lens mount - or what modification is this?


1 Answer 1


I'm pretty sure it's not Pentax K (PK) mount. It might be Nikon F (NF) mount.

  • All of the control and communication linkages are missing, but the page you link seems to indicate this is normal for that lens.
  • The alignment dot has the same position as NF.
  • The locking slots are located between the flanges, like NF. The slot would adjacent to one of the flanges on PK.
  • The position of the stop screw indicates the lens rotates counterclockwise to lock on a camera, like NF. PK rotates clockwise to lock.

Here are some images of the mounts for reference. The features noted above should be visible.

  • Nikon F mount

    Nikon F mount

  • Pentax K mount

    Pentax K mount

  • Comparison of modern Nikon fully electronic mount & modified manual Helios 44M > Nikon mount.

    enter image description here

  • \$\begingroup\$ Thanks. There is no way to know this lens had been modified... I'll have to ask for a refund. \$\endgroup\$ Nov 17, 2019 at 9:30
  • 1
    \$\begingroup\$ I found other images of this lens online that are specifically said to be "Pentax K", and there's a red dot on the silver part of the mount under the flange on there which mine doesnt have... \$\endgroup\$ Nov 17, 2019 at 9:47
  • \$\begingroup\$ NF is slightly smaller than PK. When you try to fit the lens to your camera, is it loose? Easiest way to confirm if it's NF is to try to mount it on a Nikon DSLR or NF adapter... you wouldn't happen to have or know someone who has one of those? \$\endgroup\$
    – xiota
    Nov 17, 2019 at 9:49
  • \$\begingroup\$ Ah, unfortunately I do not. When I try to fit it, it just doesn't go all the way against the PK mount of the camera body, and it's a bit wobbly, and I just can't rotate it at all. \$\endgroup\$ Nov 17, 2019 at 10:06
  • \$\begingroup\$ The K mount example is atypical :) Usually, you can spot K mounts from a mile away by there being a fat ramp/fin :) \$\endgroup\$ Nov 17, 2019 at 12:20

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