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10-14-2014, 06:53 PM   #1
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M42 adapter not working

I have just got in a new M42 adapter for all the manual lens I bought not knowing I needed an adapter. It screws on fine except when I try to try and use any lens I attach to it, the lens is all blurry? Is there a setting that I need to change it order for it to let me use the adapter?



Ok. New problem. I tried the adapater on some other lens and they work great! I tried it with a 135mm and 200mm Sears. Focused great and clear as a bell. But I have three lens that for some reason it isn't working. The Takumar 1:1.8:/55; Super Takmar 1:1.8/55; and a SMC Takumar 1:2/55 all won't focus on it. So why is it working fine for the bigger lens but won't for the others?


Last edited by majboyd; 10-14-2014 at 09:20 PM. Reason: added more
10-14-2014, 06:56 PM   #2
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QuoteOriginally posted by majboyd Quote
I have just got in a new M42 adapter for all the manual lens I bought not knowing I needed an adapter. It screws on fine except when I try to try and use any lens I attach to it, the lens is all blurry? Is there a setting that I need to change it order for it to let me use the adapter?
What adapter exactly did you get, from where? Does it have a flange that sticks outside the camera body mount or is it just a ring that goes flush inside the mount? (Post a pic if you can)
10-14-2014, 07:09 PM   #3
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If your adapter has a flange, lenses may not be able to focus to infinity. See this article:

https://www.pentaxforums.com/forums/54-pentax-lens-articles/110657-how-use-me...k-x-k-7-a.html

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10-14-2014, 08:57 PM   #4
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QuoteOriginally posted by vonBaloney Quote
What adapter exactly did you get, from where? Does it have a flange that sticks outside the camera body mount or is it just a ring that goes flush inside the mount? (Post a pic if you can)
I have one from Japan that says for Pentax K/M. I have my adapter setting set to permitted and still no nice.

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10-14-2014, 09:00 PM   #5
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That is not an M42 adapter. That is a T-ring adapter for T-mount lenses. Do not try to mount any more M42 lenses on it as the thread pitch is different.
10-14-2014, 09:03 PM   #6
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QuoteOriginally posted by boriscleto Quote
That is not an M42 adapter. That is a T-ring adapter for T-mount lenses. Do not try to mount any more M42 lenses on it as the thread pitch is different.
One more time for emphasis!!!


Steve
10-14-2014, 09:23 PM   #7
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Ok. New problem. I tried the adapater on some other lens and they work great! I tried it with a 135mm and 200mm Sears. Focused great and clear as a bell. But I have three lens that for some reason it isn't working. The Takumar 1:1.8:/55; Super Takmar 1:1.8/55; and a SMC Takumar 1:2/55 all won't focus on it. So why is it working fine for the bigger lens but won't for the others? I posted some pictures of the adapter but may have deleted them.
10-14-2014, 09:27 PM   #8
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Repeat -- do NOT screw that adapter on your m42 lenses, it will mess up the threads. That is NOT an m42 adapter.

10-14-2014, 10:22 PM   #9
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This is what you need. Pentax Mount Adapter K 30120 B&H Photo Video.

What you have is a T mount adapter, Commonly used for telescopes microscopes and low-end universal camera lenses.

It will not work on your M42 lenses!!!.. And it can damage your lens!!!. The M42 Lens has a 1 mm thread pitch. I don't remember what thread pitch the T mount used, But I know that it is a fine thread. (Not a 1 mm thread).

DO NOT USE IT.
10-14-2014, 10:40 PM   #10
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The blurriness observed in the Takumar lenses is because the registration distance is all wrong. Even if you do screw them on (DO NOT DO) it will not focus properly on the sensor .... The proper adapter mates to the camera with a slightly recessed finish, not protruding like this beast of an adapter.

The adapter you have is useful for the T2 lenses out there .... some are OK and inexpensive so keep it for those lenses.
10-15-2014, 07:50 AM   #11
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QuoteOriginally posted by vonBaloney Quote
Repeat -- do NOT screw that adapter on your m42 lenses, it will mess up the threads. That is NOT an m42 adapter.
It appears that someone is not very good at taking advice. So much for the threads on all those M42 lenses.


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10-15-2014, 08:07 AM   #12
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QuoteOriginally posted by majboyd Quote
Ok. New problem. I tried the adapater on some other lens and they work great! I tried it with a 135mm and 200mm Sears. Focused great and clear as a bell. But I have three lens that for some reason it isn't working. The Takumar 1:1.8:/55; Super Takmar 1:1.8/55; and a SMC Takumar 1:2/55 all won't focus on it. So why is it working fine for the bigger lens but won't for the others? I posted some pictures of the adapter but may have deleted them.

Your longer lenses are working and providing *some* focusing because their minimal focusing distance is further away and so this 'adapter' of yours is simply acting as a short macro extension tube. Thus giving you some focusing at short distance, but taking away your middle and infinity distance focusing. With short focal length lenses their minimal focusing distance is close and so this adapter will make them in semi-macro lenses - they will focus great at distances ~20 cm or so.

Anyway as others have said - DO NOT use this adapter on regular lenses.. that might damage the thread. You need a proper M42 - > Pentax K adapter.
10-15-2014, 08:08 AM   #13
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QuoteOriginally posted by stevebrot Quote
It appears that someone is not very good at taking advice. So much for the threads on all those M42 lenses.
Depends if he just screwed it on until met resistance or really forced it...
10-15-2014, 08:09 AM   #14
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QuoteOriginally posted by promacjoe Quote
This is what you need. Pentax Mount Adapter K 30120 B&H Photo Video.

What you have is a T mount adapter, Commonly used for telescopes microscopes and low-end universal camera lenses.

It will not work on your M42 lenses!!!.. And it can damage your lens!!!. The M42 Lens has a 1 mm thread pitch. I don't remember what thread pitch the T mount used, But I know that it is a fine thread. (Not a 1 mm thread).

DO NOT USE IT.
No wonder. It was sold to me as a M42 adapter to the K/M mounts. Thanks.

---------- Post added 10-15-14 at 10:12 AM ----------

QuoteOriginally posted by promacjoe Quote
This is what you need. Pentax Mount Adapter K 30120 B&H Photo Video.

What you have is a T mount adapter, Commonly used for telescopes microscopes and low-end universal camera lenses.

It will not work on your M42 lenses!!!.. And it can damage your lens!!!. The M42 Lens has a 1 mm thread pitch. I don't remember what thread pitch the T mount used, But I know that it is a fine thread. (Not a 1 mm thread).

DO NOT USE IT.
Thanks so much!
10-15-2014, 08:24 AM   #15
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T-mount thread pitch is 0.75mm (42 0.75mm). M42 thread pitch is 1mm (42 1mm). Many of the Non-Japan, Non-US (e.g. China, India, etc.) made M42 and T-mount adapters have a thread pitch that is somewhere in-between 1mm and 0.75mm. Sometimes either pitch will fit in them with no problem but this is rare.

If the threads are manufactured to the proper pitch and you try to put M42 in T-thread or vice versa the most you can thread them is usually less than 1/4-1/3 of a turn before it starts to bind. Forcing it will damage ("cross-thread" or strip) the screws with a typical result is that the screws will no longer thread properly in the proper application (e.g. M42 to M42). They will bind or thread loosely or not at all (stripped).

If the T-mount was bought used it may have been cross-threaded by a previous owner.

Cross-threaded mounts can usually be spotted because the anodizing or other coating of the threads will be worn off and the ridges of the threads will be rounded or flat often with another groove or notch running through them (a double thread look).

However with a T-mount you should not get infinity focus with M42 lenses as the adapter will act like an extension tube.
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