The right type of M42-to-K-mount adaptor

The right type of M42-to-K-mount adaptor · **3 Likes**

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There are two types of M42-to-K-mount adaptor:

The Flange type
The Recessed type

Don't be like me and get the wrong type, which is the Flange type. While the flange type is cheap, is commonly available and the flange appears thin, it is still thick enough to prevent focus at infinity.

Get the recessed type. I've got a "Roxsen" 3rd-party version. This is very easy to fit on a K100D Super body, but I find it is difficult to fit or remove this quickly on a K20D. The genuine Pentax M42 recessed adaptor is reported to be easier to fit compared to 3rd-party adaptors.

Here's some pictures I took showing the difference between the two M42-to-K-mount adaptors.

Recessed-type adapter plus insertion/removal key on left – Flange-type on right. Both showing the side that fits to the camera:

Flange-type fitted:

Recessed-type fitted:

Dan.

**pacerr** · 05-20-2012, 09:09 AM - **1 Like**

A very useful description and images, Dan.

For those new to the M42 adapters, it's worth noting that the design of these accessories goes back to the very beginning of the K-mount transition.

They were intended to allow people with an extensive collection of M42 lenses to continue to use them while the new K-mount lenses became easily and economically available. The intent was that the adapter would be more or less permanently mounted onto the new K-body and the M42 Takumar lenses would continue to be screw-mounted as needed. There was no special concern for the security of the M42 lenses since they fit just as designed for that type of lens.

Ironically, at that time, it was the occasional use of the new bayonet lenses that was considered inconvenient as to removing the adapter! But the ability to use the new body with older lenses was very much appreciated then, especially by pros with expensive lens collections.

I find it most convenient to dedicate a body to the use of M42 lenses with the adapter semi-permanently mounted as originally intended.

I'd also note that I've removed the flange from a few top-hat style adapters so as to prevent the "extension ring effect" on focusing to infinity and semi-permanently mounted them to certain often-used M42 lenses in effect making them PK lenses but without the latching notch (which can be drilled into the base if desired in some cases). When I do that, I intentionally shave the adapter so the lens fits with the aperture index at the 10- or 2-o'clock position so the internal flash bulge doesn't interfere with reading the aperture ring. (Lens registry distance depends on the lens base-to-body fit, not a specific thread alignment for either type of mount.)

H2

vonBaloney · 05-20-2012, 10:26 AM

The flange-type lose infinity focus but they are more convenient for certain uses. Since they have that notch for the locking pin, it is easy to remove them bayonet-style with the lens but still allow secure locking when in place (unlike the recessed type with the lock removed so you can leave it on the lens -- it is insecure). It is also possible to unscrew the lens just as easily (to leave the adapter on the camera) simply by NOT pressing the lens release button and unscrewing. I use most of my m42s for close-work, so the flange-types are a bit faster and easier to work with, and I don't mind getting the few extra inches on the close end and losing infinity (most of the time). Bottom-line -- get a few of both types!

BTW -- do those Roxsen cheapies allow the lens to face the right way? Overstock.com actually had m42 adapters available for a few bucks -- I ordered like 8 of them but the threads were such that all the lenses ended up upside-down when screwed in. Returned them all...

RioRico · 05-21-2012, 10:22 PM - **1 Like**

I distinguish between 3 types of adapters:

1) The Official Pentax M42-PK adapter -- safe, a bit tedious (since it stays mounted in the camera), not very cheap. IMHO anyone with at least one M42 lens should own just one of these. This, and the clones, should all allow infinity focus.

2) Clones of The Official one, all narrow-flange -- cheap, sold as various brands. I'm most familiar with those stamped BOWER. These adapters are fine but you must remove the screw+clip or YOU WILL GO APESH!T! The clip easily jams the adapter on the camera mount. I have many many M42 lenses, and dozens of such adapters, which usually reside on the lenses. I've had some mounted for so long, I've almost forgotten they're not native PK mount. Use a PK rear lens cap to wrench the adapter on|off the lens.

3) Wide-flange NIF (no infinity focus) adapters -- safe, cheap, foolproof. I use these with some old telephotos that normally focus PAST infinity, and in situations where infinity doesn't matter: with extension (bellows, tubes, helicoids), and lenses for macro, close, and portrait work. These are also good for enabling CIF (catch-in-focus) with narrow-body screwmount lenses.

I also use M39 lenses, mostly Russians made for Zenit SLRs, same thread as Leica L39/LTM but the same register as M42 and PK. Also L39 lens (mostly for enlargers) with the same thread but no register. I may fit an M39-M42 adapter ring into a narrow-flange M42-PK adapter; or with L39 enlarger lenses, I may use a wide+thick-flange M39-PK adapter, also safe and cheap. BEWARE: It's too easy to buy an LTM (Leica threadmount) lens expecting it to be M39; but it ain't, and it won't work on a Pentax dSLR. Learning the differences between M39 and L39 can get expensive. Stick with M42.

Leonardo da Vinci · 10-04-2012, 09:36 AM

Originally posted by pacerr

I'd also note that I've removed the flange from a few top-hat style adapters so as to prevent the "extension ring effect" on focusing to infinity and semi-permanently mounted them to certain often-used M42 lenses in effect making them PK lenses but without the latching notch (which can be drilled into the base if desired in some cases). When I do that, I intentionally shave the adapter so the lens fits with the aperture index at the 10- or 2-o'clock position so the internal flash bulge doesn't interfere with reading the aperture ring. (Lens registry distance depends on the lens base-to-body fit, not a specific thread alignment for either type of mount.)
H2

pacerr

Can you do put photos from your work (flange modified)

Thanks very much

L

Prakticant · 01-06-2015, 06:25 AM

Originally posted by RioRico

These are also good for enabling CIF (catch-in-focus) with narrow-body screwmount lenses.

Is there any special requirement for CIF to be enabled with Adapter B / M42 glass?
Like making short electric contacts (pins) of the camera body?

Perro1 · 04-10-2016, 03:15 PM

Why my Super Takumar doesn't reach infinity focus with recessed type and K-5?

vonBaloney · 04-10-2016, 03:38 PM

Originally posted by Perro1

Why my Super Takumar doesn't reach infinity focus with recessed type and K-5?

It is not completely uncommon for them to be off -- just because or maybe someone adjusted it for another camera. They are fairly easy to adjust if you don't mind loosening a few screws...

Perro1 · 04-10-2016, 04:23 PM

Originally posted by vonBaloney

It is not completely uncommon for them to be off -- just because or maybe someone adjusted it for another camera. They are fairly easy to adjust if you don't mind loosening a few screws...

Can you paste me some link, please, how to do that?

vonBaloney · 04-10-2016, 08:00 PM

Originally posted by Perro1

Can you paste me some link, please, how to do that?

Which lens exactly are we talking about?

Perro1 · 04-11-2016, 12:35 AM

Originally posted by vonBaloney

Which lens exactly are we talking about?

Super Takumar 50mm f/1.4 7 blades. It works and reaches infinity on my Sony and Canon cameras with adapters. I don't know why it doesn't work on K-5.. but I solved it. It wasn't the lens but flange distance on cheap adapter. I brushed it with sandpaper about 1/3 of mm and now it works perfect.

gybp · 06-24-2016, 03:40 AM

Hi, i just bought my first M42 lens, the ASAHI PENTAX SUPER-TAKUMAR 200MM f4 M42 Mount, and i need an adaptor for my Pentax K-50. Wich adapter should i get? Can you point me to a reliable ebay seller (or amazon) that sells it?? Thanks!

Perro1 · 06-25-2016, 01:31 AM

Originally posted by gybp

Hi, i just bought my first M42 lens, the ASAHI PENTAX SUPER-TAKUMAR 200MM f4 M42 Mount, and i need an adaptor for my Pentax K-50. Wich adapter should i get? Can you point me to a reliable ebay seller (or amazon) that sells it?? Thanks!

It's hard to say which of cheap adapters works well, but if you buy original Asahi M42 to PK, you wouldn't go wrong. It costs about 50$. But if you consider buying cheap one - be sure it's recessive type. This one looks ok, but I don't have personal experince with it. M42 Lens to PK Pentax K Mount Adapter for K 5 K R K x K7 K M K20D K200D DSLR | eBay

**kernos** · 06-25-2016, 12:18 PM

So, I hear that folks really like the genuine Pentax to M42 adapter. And then if you look into it, folks are gluing the aperture pins or doing lens surgery or shooting wide open. I have both the genuine Pentax and the Kipon adapters. The Kipon adapter will depress the aperture pin and let you do stop down metering. The Pentax adapter will not. The Kipon and the Pentax adapters are both flangeless and both will focus to infinity. Neither is easy to remove with perhaps the Kipon being harder, but I have a K30 with a bricked aperture control block that only shoots M42 lenses so the adapter stays put. Both are beautifully made. So, for me the choice seems easy, but YMMV. But do look at the Kipon. For some uses, it will make your life easier.

Almost forgot to mention. I have a Helios 77m-4 that does not wobble in the adapter. None of my lenses, including an ancient narrow preset that exposes the contacts on my K30, wobble. I've heard other folks with wobble issues with the genuine adapter.

vonBaloney · 06-25-2016, 12:39 PM

Originally posted by kernos

So, I hear that folks really like the genuine Pentax to M42 adapter. And then if you look into it, folks are gluing the aperture pins or doing lens surgery or shooting wide open. I have both the genuine Pentax and the Kipon adapters. The Kipon adapter will depress the aperture pin and let you do stop down metering. The Pentax adapter will not. The Kipon and the Pentax adapters are both flangeless and both will focus to infinity. Neither is easy to remove with perhaps the Kipon being harder, but I have a K30 with a bricked aperture control block that only shoots M42 lenses so the adapter stays put. Both are beautifully made. So, for me the choice seems easy, but YMMV. But do look at the Kipon. For some uses, it will make your life easier.

Almost forgot to mention. I have a Helios 77m-4 that does not wobble in the adapter. None of my lenses, including an ancient narrow preset that exposes the contacts on my K30, wobble. I've heard other folks with wobble issues with the genuine adapter.

Interesting -- might have to pick one of those up. But to be fair, not many lenses need the aperture pin held down (Takumars don't, in general) because most have a switch and if they do have a switch I don't want it held down as it is nice to be able to flip the switch back to wide-open. The issue with narrow-based lenses is usually more about light-leaks than wobble. Most of my m42s end up with a semi-permanent cheapo adapter with the spring removed so I can use them like K-mounts, but the genuine adapter is good to have around for testing and lesser-used lenses. (I make sure to have one in my bag if I'm going anywhere where I might be looking at old used lenses so I can try them out without danger.)

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01-06-2015, 06:25 AM	#6
Prakticant Senior Member Join Date: Jul 2010 Posts: 274	M42 and Catch-In-Focus (K-5 IIs / K-3) Originally posted by RioRico These are also good for enabling CIF (catch-in-focus) with narrow-body screwmount lenses. Is there any special requirement for CIF to be enabled with Adapter B / M42 glass? Like making short electric contacts (pins) of the camera body?

04-11-2016, 12:35 AM	#11
Perro1 New Member Join Date: Mar 2016 Location: Zagreb Posts: 27	Originally posted by vonBaloney Which lens exactly are we talking about? Super Takumar 50mm f/1.4 7 blades. It works and reaches infinity on my Sony and Canon cameras with adapters. I don't know why it doesn't work on K-5.. but I solved it. It wasn't the lens but flange distance on cheap adapter. I brushed it with sandpaper about 1/3 of mm and now it works perfect. Last edited by Perro1; 04-11-2016 at 10:06 AM.

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05-20-2012, 09:09 AM - 1 Like	#2
pacerr Loyal Site Supporter Join Date: Jan 2008 Location: Paris, TN Photos: Gallery \| Albums Posts: 3,349	A very useful description and images, Dan. For those new to the M42 adapters, it's worth noting that the design of these accessories goes back to the very beginning of the K-mount transition. They were intended to allow people with an extensive collection of M42 lenses to continue to use them while the new K-mount lenses became easily and economically available. The intent was that the adapter would be more or less permanently mounted onto the new K-body and the M42 Takumar lenses would continue to be screw-mounted as needed. There was no special concern for the security of the M42 lenses since they fit just as designed for that type of lens. Ironically, at that time, it was the occasional use of the new bayonet lenses that was considered inconvenient as to removing the adapter! But the ability to use the new body with older lenses was very much appreciated then, especially by pros with expensive lens collections. I find it most convenient to dedicate a body to the use of M42 lenses with the adapter semi-permanently mounted as originally intended. I'd also note that I've removed the flange from a few top-hat style adapters so as to prevent the "extension ring effect" on focusing to infinity and semi-permanently mounted them to certain often-used M42 lenses in effect making them PK lenses but without the latching notch (which can be drilled into the base if desired in some cases). When I do that, I intentionally shave the adapter so the lens fits with the aperture index at the 10- or 2-o'clock position so the internal flash bulge doesn't interfere with reading the aperture ring. (Lens registry distance depends on the lens base-to-body fit, not a specific thread alignment for either type of mount.) H2

05-20-2012, 10:26 AM	#3
vonBaloney Pentaxian Join Date: Oct 2011 Location: Albuquerque, NM Posts: 6,029	The flange-type lose infinity focus but they are more convenient for certain uses. Since they have that notch for the locking pin, it is easy to remove them bayonet-style with the lens but still allow secure locking when in place (unlike the recessed type with the lock removed so you can leave it on the lens -- it is insecure). It is also possible to unscrew the lens just as easily (to leave the adapter on the camera) simply by NOT pressing the lens release button and unscrewing. I use most of my m42s for close-work, so the flange-types are a bit faster and easier to work with, and I don't mind getting the few extra inches on the close end and losing infinity (most of the time). Bottom-line -- get a few of both types! BTW -- do those Roxsen cheapies allow the lens to face the right way? Overstock.com actually had m42 adapters available for a few bucks -- I ordered like 8 of them but the threads were such that all the lenses ended up upside-down when screwed in. Returned them all...

05-21-2012, 10:22 PM - 1 Like	#4
RioRico Veteran Member Join Date: Jun 2008 Location: Limbo, California Posts: 11,263	I distinguish between 3 types of adapters: 1) The Official Pentax M42-PK adapter -- safe, a bit tedious (since it stays mounted in the camera), not very cheap. IMHO anyone with at least one M42 lens should own just one of these. This, and the clones, should all allow infinity focus. 2) Clones of The Official one, all narrow-flange -- cheap, sold as various brands. I'm most familiar with those stamped BOWER. These adapters are fine but you must remove the screw+clip or YOU WILL GO APESH!T! The clip easily jams the adapter on the camera mount. I have many many M42 lenses, and dozens of such adapters, which usually reside on the lenses. I've had some mounted for so long, I've almost forgotten they're not native PK mount. Use a PK rear lens cap to wrench the adapter on\|off the lens. 3) Wide-flange NIF (no infinity focus) adapters -- safe, cheap, foolproof. I use these with some old telephotos that normally focus PAST infinity, and in situations where infinity doesn't matter: with extension (bellows, tubes, helicoids), and lenses for macro, close, and portrait work. These are also good for enabling CIF (catch-in-focus) with narrow-body screwmount lenses. I also use M39 lenses, mostly Russians made for Zenit SLRs, same thread as Leica L39/LTM but the same register as M42 and PK. Also L39 lens (mostly for enlargers) with the same thread but no register. I may fit an M39-M42 adapter ring into a narrow-flange M42-PK adapter; or with L39 enlarger lenses, I may use a wide+thick-flange M39-PK adapter, also safe and cheap. BEWARE: It's too easy to buy an LTM (Leica threadmount) lens expecting it to be M39; but it ain't, and it won't work on a Pentax dSLR. Learning the differences between M39 and L39 can get expensive. Stick with M42.

10-04-2012, 09:36 AM	#5
Leonardo da Vinci New Member Join Date: Sep 2012 Location: Santiago Posts: 22	Originally posted by pacerr I'd also note that I've removed the flange from a few top-hat style adapters so as to prevent the "extension ring effect" on focusing to infinity and semi-permanently mounted them to certain often-used M42 lenses in effect making them PK lenses but without the latching notch (which can be drilled into the base if desired in some cases). When I do that, I intentionally shave the adapter so the lens fits with the aperture index at the 10- or 2-o'clock position so the internal flash bulge doesn't interfere with reading the aperture ring. (Lens registry distance depends on the lens base-to-body fit, not a specific thread alignment for either type of mount.) H2 pacerr Can you do put photos from your work (flange modified) Thanks very much L

04-10-2016, 03:15 PM	#7
Perro1 New Member Join Date: Mar 2016 Location: Zagreb Posts: 27	Why my Super Takumar doesn't reach infinity focus with recessed type and K-5?

04-10-2016, 03:38 PM	#8
vonBaloney Pentaxian Join Date: Oct 2011 Location: Albuquerque, NM Posts: 6,029	Originally posted by Perro1 Why my Super Takumar doesn't reach infinity focus with recessed type and K-5? It is not completely uncommon for them to be off -- just because or maybe someone adjusted it for another camera. They are fairly easy to adjust if you don't mind loosening a few screws...

04-10-2016, 04:23 PM	#9
Perro1 New Member Join Date: Mar 2016 Location: Zagreb Posts: 27	Originally posted by vonBaloney It is not completely uncommon for them to be off -- just because or maybe someone adjusted it for another camera. They are fairly easy to adjust if you don't mind loosening a few screws... Can you paste me some link, please, how to do that?

04-10-2016, 08:00 PM	#10
vonBaloney Pentaxian Join Date: Oct 2011 Location: Albuquerque, NM Posts: 6,029	Originally posted by Perro1 Can you paste me some link, please, how to do that? Which lens exactly are we talking about?

06-24-2016, 03:40 AM	#12
gybp Senior Member Join Date: Nov 2009 Photos: Gallery Posts: 165	Hi, i just bought my first M42 lens, the ASAHI PENTAX SUPER-TAKUMAR 200MM f4 M42 Mount, and i need an adaptor for my Pentax K-50. Wich adapter should i get? Can you point me to a reliable ebay seller (or amazon) that sells it?? Thanks!

06-25-2016, 01:31 AM	#13
Perro1 New Member Join Date: Mar 2016 Location: Zagreb Posts: 27	Originally posted by gybp Hi, i just bought my first M42 lens, the ASAHI PENTAX SUPER-TAKUMAR 200MM f4 M42 Mount, and i need an adaptor for my Pentax K-50. Wich adapter should i get? Can you point me to a reliable ebay seller (or amazon) that sells it?? Thanks! It's hard to say which of cheap adapters works well, but if you buy original Asahi M42 to PK, you wouldn't go wrong. It costs about 50$. But if you consider buying cheap one - be sure it's recessive type. This one looks ok, but I don't have personal experince with it. M42 Lens to PK Pentax K Mount Adapter for K 5 K R K x K7 K M K20D K200D DSLR \| eBay

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06-25-2016, 12:18 PM	#14
kernos Site Supporter Join Date: Feb 2013 Posts: 456	So, I hear that folks really like the genuine Pentax to M42 adapter. And then if you look into it, folks are gluing the aperture pins or doing lens surgery or shooting wide open. I have both the genuine Pentax and the Kipon adapters. The Kipon adapter will depress the aperture pin and let you do stop down metering. The Pentax adapter will not. The Kipon and the Pentax adapters are both flangeless and both will focus to infinity. Neither is easy to remove with perhaps the Kipon being harder, but I have a K30 with a bricked aperture control block that only shoots M42 lenses so the adapter stays put. Both are beautifully made. So, for me the choice seems easy, but YMMV. But do look at the Kipon. For some uses, it will make your life easier. Almost forgot to mention. I have a Helios 77m-4 that does not wobble in the adapter. None of my lenses, including an ancient narrow preset that exposes the contacts on my K30, wobble. I've heard other folks with wobble issues with the genuine adapter.

06-25-2016, 12:39 PM	#15
vonBaloney Pentaxian Join Date: Oct 2011 Location: Albuquerque, NM Posts: 6,029	Originally posted by kernos So, I hear that folks really like the genuine Pentax to M42 adapter. And then if you look into it, folks are gluing the aperture pins or doing lens surgery or shooting wide open. I have both the genuine Pentax and the Kipon adapters. The Kipon adapter will depress the aperture pin and let you do stop down metering. The Pentax adapter will not. The Kipon and the Pentax adapters are both flangeless and both will focus to infinity. Neither is easy to remove with perhaps the Kipon being harder, but I have a K30 with a bricked aperture control block that only shoots M42 lenses so the adapter stays put. Both are beautifully made. So, for me the choice seems easy, but YMMV. But do look at the Kipon. For some uses, it will make your life easier. Almost forgot to mention. I have a Helios 77m-4 that does not wobble in the adapter. None of my lenses, including an ancient narrow preset that exposes the contacts on my K30, wobble. I've heard other folks with wobble issues with the genuine adapter. Interesting -- might have to pick one of those up. But to be fair, not many lenses need the aperture pin held down (Takumars don't, in general) because most have a switch and if they do have a switch I don't want it held down as it is nice to be able to flip the switch back to wide-open. The issue with narrow-based lenses is usually more about light-leaks than wobble. Most of my m42s end up with a semi-permanent cheapo adapter with the spring removed so I can use them like K-mounts, but the genuine adapter is good to have around for testing and lesser-used lenses. (I make sure to have one in my bag if I'm going anywhere where I might be looking at old used lenses so I can try them out without danger.)