[Marc D.]

Guys, hello !

I have bought a Samyang FF 20 mm f1.8 lens, marvellous for it's image quality, but i had immediatly the problem to unmount the lens after usage on a K-1 : the lens does not goes out.
I was in A mode on the aperture ring. I have discovered that the "Pentax" mount was a "KR" mount (Thanks the vendor)
Finally i achieved unmounting the lens putting the aperture so some aperture value instead of the A value. The pin retracts. But in this mode I obviously can't use the automatic exp. settings from the body.

Is it dangerous for the body mount keeping this PIN ?
Do I have to remove this PIN ?
If I do that, does the A mode continue to work without this PIN ?

I have some Sigma with aperture ring and A mode that do work in A mode absolutely properly without this pin.
I want to use the A mode.

... Or do I through away this lens and the money it costed ?

In fact I have many two other Samyang (35 and 80) not marked KR but with a (lower erectil (!!)) Ricoh Pin in A mode. They do not cause problem at remove ... because the pin is not so tall.

including two photos

have a good day. and thank you for your attention.

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Last edited by Marc D.; 04-04-2023 at 10:19 PM.

[JensE]

This is not the Ricoh pin, just your normal A-series contact, signalling whether the aperture ring is in the A-setting, see Features and Operation of the KA Mount | The K-Mount Page, the '“A” Setting on the Aperture Ring' section, for an explanation. Yours just seems to be mechanically not quite correct, normally it should be able to slide out of the dimple (slightly recessed contact) on the camera bayonet for a lens change. It should be spring-loaded and be give way when you gently push it in. More modern lenses use an internal switch, but at least my A24/2.8 uses the mechanical approach to disengage.

Unless you're immensely annoyed by it, moving the aperture ring out of the A-setting before changing the lens sounds like a viable and safe workaround, and even a repair should be simple.

[Marc D.]

This is not the Ricoh pin, just your normal A-series contact, signalling whether the aperture ring is in the A-setting, see Features and Operation of the KA Mount | The K-Mount Page, the '“A” Setting on the Aperture Ring' section, for an explanation. Yours just seems to be mechanically not quite correct, normally it should be able to slide out of the dimple (slightly recessed contact) on the camera bayonet for a lens change. It should be spring-loaded and be give way when you gently push it in. More modern lenses use an internal switch, but at least my A24/2.8 uses the mechanical approach to disengage.

Unless you're immensely annoyed by it, moving the aperture ring out of the A-setting before changing the lens sounds like a viable and safe workaround, and even a repair should be simple.

Thanks for your reply JensE. I'm not so much afraid breaking my K-1 body mount with this lens.
Still remains this "KR" inscription on the lens that is a little bit strange.

Have a good day.
Marc

[Nai1975]

Hello Marc, I have Rokinon 16 2.0 lens. (The same as Samyang, they just changed the trade mark). It has the same KR text on lens. I don’t have any issues with my Pentax KP bayonet. So it looks like problem with your lens item. By design everything has to work with “A” aperture selected.

[bwgv001]

I do have the exact same lens. Also says KR (in red); never had any problems unmounting. But, my mount looks different

[Just1MoreDave]

You should be able to mount the lens with the aperture ring at any aperture. Then when the lens is mounted fully, turn the ring back to A. Then use the automatic exposure settings from the body.

The pin is supposed to have a spring behind it. You should be able to push it back, level with the mount, when it's protruding (ring in the A position). When the lens rotates on the mount, it springs back into the mount, then when it reaches the right contact on the camera, it can spring out. The camera contact is slightly recessed. The pin may be slightly too long and jamming instead of springing back.

If my suggestion works, I would just do that every time. You could file the pin a little but you'd have to tape off everything to keep filings out of the lens. Pentax lenses have much rounder ends.

[Not a Number]

"KR" mount designations usually mean Pentax K / Ricoh. Neither of mounts pictured above have the Ricoh pin.

You could probably take the rear mount off and remove the pin temporarily to file it down. You would have to treat the lens as a K or M series lens, e.g. manual mode green button metering without the A pin.

[Marc D.]

Hello Marc, I have Rokinon 16 2.0 lens. (The same as Samyang, they just changed the trade mark). It has the same KR text on lens. I don’t have any issues with my Pentax KP bayonet. So it looks like problem with your lens item. By design everything has to work with “A” aperture selected.

Yes you are right. I have also 3 Samyangs with the "A"/pin and only one of them does not support the unmount operation. The overt two acept the unmount. I've looked and see that the Samyang 20 f1,8 has a more "erectil pin" !!! Twice the others pin of my others Samyang (35 and 80).
But I have also some Sigma with the aperture ring including the "A" position WITHOUT any pin !

Thank you for your communitacion on this subjet.

---------- Post added 05-02-23 at 10:01 PM ----------

You should be able to mount the lens with the aperture ring at any aperture. Then when the lens is mounted fully, turn the ring back to A. Then use the automatic exposure settings from the body.

The pin is supposed to have a spring behind it. You should be able to push it back, level with the mount, when it's protruding (ring in the A position). When the lens rotates on the mount, it springs back into the mount, then when it reaches the right contact on the camera, it can spring out. The camera contact is slightly recessed. The pin may be slightly too long and jamming instead of springing back.

If my suggestion works, I would just do that every time. You could file the pin a little but you'd have to tape off everything to keep filings out of the lens. Pentax lenses have much rounder ends.

I will do that. Prying that the spring wil ever work. Thanks a lot for the advise.

---------- Post added 05-02-23 at 10:04 PM ----------

You should be able to mount the lens with the aperture ring at any aperture. Then when the lens is mounted fully, turn the ring back to A. Then use the automatic exposure settings from the body.

The pin is supposed to have a spring behind it. You should be able to push it back, level with the mount, when it's protruding (ring in the A position). When the lens rotates on the mount, it springs back into the mount, then when it reaches the right contact on the camera, it can spring out. The camera contact is slightly recessed. The pin may be slightly too long and jamming instead of springing back.

If my suggestion works, I would just do that every time. You could file the pin a little but you'd have to tape off everything to keep filings out of the lens. Pentax lenses have much rounder ends.

I will do that. Prying that the spring wil ever work. Thanks a lot for the advise.

---------- Post added 05-02-23 at 10:06 PM ----------

You should be able to mount the lens with the aperture ring at any aperture. Then when the lens is mounted fully, turn the ring back to A. Then use the automatic exposure settings from the body.

The pin is supposed to have a spring behind it. You should be able to push it back, level with the mount, when it's protruding (ring in the A position). When the lens rotates on the mount, it springs back into the mount, then when it reaches the right contact on the camera, it can spring out. The camera contact is slightly recessed. The pin may be slightly too long and jamming instead of springing back.

If my suggestion works, I would just do that every time. You could file the pin a little but you'd have to tape off everything to keep filings out of the lens. Pentax lenses have much rounder ends.

I will do that. Prying that the spring wil ever work. Thanks a lot for the advise.

[Marc D.]

thank you all again for the informations in the answers. I have a last question please :
To be liberate of the stress of this "A" pin blocking the unmount of the lens, can I remove the pin KEEPING the A mode available ?
I ask because I have some Sigma lens (105 macro, 10-20 EX) for Pentax that DO NOT have this pin but have an A mode on the aperture ring ad its works !
thanks for your attention.

[JensE]

thank you all again for the informations in the answers. I have a last question please :
To be liberate of the stress of this "A" pin blocking the unmount of the lens, can I remove the pin KEEPING the A mode available ?
I ask because I have some Sigma lens (105 macro, 10-20 EX) for Pentax that DO NOT have this pin but have an A mode on the aperture ring ad its works !
thanks for your attention.

You need the pin - just get used to move the lens out of A-mode to unmount it. If you're not convinced by the explanation above, just isolate the pin with some thin insulating tape or a piece of paper as a test.

[Dan]

You need the pin - just get used to move the lens out of A-mode to unmount it. If you're not convinced by the explanation above, just isolate the pin with some thin insulating tape or a piece of paper as a test.

Yes, moving the lens out of A-mode should cause the pin to retract into the mount. You can test this out while the lens is unmounted. Take a look at the pin as you move the aperture dial away from the "A" setting. If the pin doesn't retract then there is something wrong with your lens.

Having said this, your pin does seem to stick out too far. You may want to repeat the above procedure a few times, moving the lens into-and-out-of A-mode while the lens is off the camera. That may help to loosen the pin.

As for the KR label, I have the same designation on most of my K-mount Samyang/Rokinon lenses, including the 8mm, 10mm, 12mm, 14mm and 16mm. The KR designation is absent from my 35mm.

Samyang makes some nice lenses!

Dan

[Marc D.]

Thank you all. I think the thread is closed.