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03-22-2021, 06:13 PM   #1
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How to identify a genuine Pentax M42-K adapter?

Does this one look genuine?
Locking mechanism

03-22-2021, 06:21 PM   #2
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No, not a genuine adapter.

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Newer ones say Pentax Philippines.

Last edited by boriscleto; 03-22-2021 at 06:29 PM.
03-22-2021, 08:21 PM   #3
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Genuine adapters will be marked "ASAHI PENTAX JAPAN", "PENTAX JAPAN" or "PENTAX PHILIPPINES" depending on when made (oldest to newest). Always in all capital engraved letters.

Last edited by Not a Number; 03-23-2021 at 12:46 PM.
03-23-2021, 05:11 AM   #4
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IME all the Japan made ones are good.

M42-PK adapters - some personal experiences

unfortunately the images are now gone, but I think the second one described in the post was similar to the one you ask about.

03-23-2021, 08:56 AM   #5
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QuoteOriginally posted by Pentaxxoid Quote
Does this one look genuine?
Locking mechanism
Nope, and if considering that one I would stay away. It may provide infinity focus but it looks like it may have been abused or just really poorly made. I would be afraid it would get stuck on or not stay on at all.
03-23-2021, 09:14 AM   #6
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I take one of 2 approaches with adapters: I have the genuine ones I use mainly with the really stiff old lenses, like the 35/2.3, and for lenses like the 50/1.4 or 55, I buy the fotodiox adapters, remove the clip, and then put them on the lens just a tiny bit tighter than hand tight.

I don't do this with the 35 because the focus is a little stiff, and focusing will cause the lens to rotate in the mount, so I need the retainer clip. For the 50's, they focus like butter, and the friction of the mount keeps them in place. For my helios 58mm, I actually epoxied a fotodiox adapter onto the lens because of light leaks through the little cutouts. I had to fill those in with epoxy and just made it permanent to the lens. (no clip, obviously).
03-23-2021, 11:15 AM   #7
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If you search an original one do not consider thi message but if you search for a good adapter also by other brand there is the Kipon that is useful if you have some german lenses like the Zeiss Jena 35mm F2.8, th Zeiss Jena 135 F3.5 and the Pentacon 50mm F1.8 (these are that I have but probably there are more like these) that have a small piece of metal that can not be disabled, with this adapter the blades of diaphragm close when you change the diaphragm on the optic.

03-23-2021, 12:43 PM   #8
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How to tell id a genuine adapter? As noted above, labeling in a clue, though not water tight. Another clue is whether it comes with the original Pentax packaging (green ziploc packet or readily identifiable box). Down to the nitty gritty is whether it is made like the genuine, the most obvious attribute is (drum roll):
Whether both the tang end above the red dot and that adjacent to the locking spring are square cut rather than chamfered.
Both are important design compatibility features and both are typically chamfered on 3rd-party/brand-X offerings.

(On my todo list has been to create an illustration pointing out those and other points of compatibility. I will update this post if I do so in the near future.)


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