M42 to K mount issue

winglik · 12-13-2008, 05:40 PM

I just bought an T-adapter for my screw mount lenses for Pentax K10D. the adapter fits, but I can't get a good focus for most my lenses, focus only works with the 135mm lems. This adapter is Vivitar Brand, and i saw the same kind of adapter on B&H, i asked them, they said the T-adapter is same as M42 Screw mount adapter. The style of the adapter is different than the normal flat adapter. It's not flat to the mount, when it mounts to the camera, it has about 5/16" that extended out. also the lens didn't screw in completely,there is a 2/16 gap between the lens and the adapter base. (see pic 2) I bought this type instead of the flat one because i thought this one is easier to remove. but i think i made a bad choice. Any help is welcomed. thank you!

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Last edited by winglik; 12-13-2008 at 05:52 PM.

Ole · 12-13-2008, 05:43 PM

This is the one you want, if you want to be able to focus to infinity. It sits flush with the camera mount:

Genuine Pentax Screwmount Lens Adapter

KungPOW · 12-13-2008, 05:47 PM

Adapters that have the flange, will always mess with the focus on an M42 lens.

The best adapter to get is the genuine Pentax. It fits entirely into the mount, and does not affect the lenses registration distance.

I also understand that a "T-adapter" is used to conect a telescope to a pentax camera, and is not intended for an M42 lens.

Here is a link to Hin's info about the Pentax adapter:

Genuine Pentax M42 to K Adapter - Hin's Tech Corner

winglik · 12-13-2008, 05:54 PM

Thanx for reply. That means the B&H guy gave me the wrong info. That guy mislead me that T-adapter is same as M42 Screw adapter. But i searched "M42 adapter" on B&H site, and they all show up the same adapter. see link below. So does that mean B&H is wrong on M42 adapter?

http://www.bhphotovideo.com/c/product/276088-REG/Kowa_TSPK_A_T_Mount_SLR_Camera_Adapter.html

stevebrot · 12-13-2008, 06:12 PM

Originally posted by winglik

Thanx for reply. That means the B&H guy gave me the wrong info. That guy mislead me that T-adapter is same as M42 Screw adapter. But ihttps://www.pentaxforums.com/forums/newreply.php?do=newreply&p=418081 searched "M42 adapter" on B&H site, and they all show up the same adapter. see link below. So is that mean the who B&H is wrong on M42 adapter?

Kowa | T-Mount SLR Camera Adapter for Pentax | TSPK-A | B&H

The T-mount is 42mm, but not the same as M-42. Different thread pitch. B&H sells an adapter that should work:

General Brand | Pentax-K Body to Universal Lens Adapter | B&H

The official Pentax adapter is better:

PentaxWebstore Mount Adapter B (35mm Screwmount to Bayonet)

Good luck!

Steve

(BTW, I hope you did not damage the threads on any of your M-42 lenses trying to screw them into the T-mount...)

winglik · 12-13-2008, 06:24 PM

Thank you for clearing that up. If the guy on B&H is knowledge enough, i wouldn't have all these trouble. Another lesson. Thanx

henryp · 12-15-2008, 10:05 AM

Originally posted by winglik

Thanx for reply. That means the B&H guy gave me the wrong info. That guy mislead me that T-adapter is same as M42 Screw adapter.

Apparently our sales associate made a mistake. I am sorry he did and if I could ID you or this transaction (which I cannot) I'd be happy to review this with him and his sales manager. I do not believe it was his intent to mislead you. Rather, he made a mistake. Nevertheless, I apologize. I am sure customer service will be happy to help you make the appropriate exchange.

Mike Cash · 12-15-2008, 11:51 AM

Originally posted by henryp

Apparently our sales associate made a mistake. I am sorry he did and if I could ID you or this transaction (which I cannot) I'd be happy to review this with him and his sales manager. I do not believe it was his intent to mislead you. Rather, he made a mistake. Nevertheless, I apologize. I am sure customer service will be happy to help you make the appropriate exchange.

It would be really nice if B&H offered to compensate him for any damage done to his lens mount due to their error.

noblepa · 12-15-2008, 12:03 PM

The t-mount system is not intended to adapt one native camera mount to another, the way an M42-K, or an M42-Canon EOS adapter does.

T-mount adapters can ONLY be used with t-mount lenses. Back in the day, many third-party manufacturers, such as Vivitar, Soligor and Tamron, made lenses that used this system. As you noted, the adapter is quite thick, compared to an M42-K adapter. This is because the registration distance of a t-mount lens is much longer than the M42, to allow for the adapter. ALL t-mount lenses MUST use an adapter. As far as I know, there was never a camera made, for which t-mounts were the native lenses. They ALL required an adapter.

The t-mount system died out in popularity, because it only allowed manual or preset aperture control. There was no capability of even automatically stopping the aperture down to the working stop. Vivitar and Soligor attempted to correct this, with the T-4 system, but it, too has died out completely.

Tamron tried to keep the concept of a universal lens mount system alive, with their Adaptall and Adaptall II systems, but I believe that they have stopped making those and are just selling off existing stocks.

The original t-mount system is still used for cheap mirror and refracting lenses, such as the 500mm, f/8.0 lenses you see on eBay for $100 new.

The t-mount thread is 42mm x 0.75 threads/mm. The M42 (Pentax screw mount) is 42mm x 1.0 tpmm. IOW, t-mount is fine thread; M42 is coarse. You can damage an M42 lens by trying to screw it into a t-mount adapter.

Paul Noble

winglik · 12-16-2008, 03:47 AM

Originally posted by henryp

Apparently our sales associate made a mistake. I am sorry he did and if I could ID you or this transaction (which I cannot) I'd be happy to review this with him and his sales manager. I do not believe it was his intent to mislead you. Rather, he made a mistake. Nevertheless, I apologize. I am sure customer service will be happy to help you make the appropriate exchange.

Thanx, Maybe it just a little mixed up by the salesperson. I know B&H is a pro store when it comes to camera. but anyway. Thanx all your help. I learned a lot from all of you.

titrisol · 12-16-2008, 04:47 AM

T-mounts were sort of a universal mount pushed by the 3rd parties manufacturers.
The screw is also 42mm but the thread is different so M42 lenses will only screw partly.

There are still some T lenses and slide copiers for sale, even new so the adapter maybe very useful, keep it.

There are adapters for Pentax, nikon, Canon, Minolta, etc etc etc and the T-mount lenses are quite cheap in eekPay

**Douglas_of_Sweden** · 12-16-2008, 06:24 AM

Originally posted by winglik

Thanx, Maybe it just a little mixed up by the salesperson. I know B&H is a pro store when it comes to camera. but anyway. Thanx all your help. I learned a lot from all of you.

In any case, check the threads on the m42 lenses where you tried the T adapter. You can damage the threads this way, and you may not notice the problem until you later try to mount a correct m42 adapter. If this is the case, you should be compensated, if you ask me.

12-15-2008, 12:03 PM	#9
noblepa Veteran Member Join Date: Sep 2007 Location: Bay Village, Ohio USA Posts: 1,142	T-Mount The t-mount system is not intended to adapt one native camera mount to another, the way an M42-K, or an M42-Canon EOS adapter does. T-mount adapters can ONLY be used with t-mount lenses. Back in the day, many third-party manufacturers, such as Vivitar, Soligor and Tamron, made lenses that used this system. As you noted, the adapter is quite thick, compared to an M42-K adapter. This is because the registration distance of a t-mount lens is much longer than the M42, to allow for the adapter. ALL t-mount lenses MUST use an adapter. As far as I know, there was never a camera made, for which t-mounts were the native lenses. They ALL required an adapter. The t-mount system died out in popularity, because it only allowed manual or preset aperture control. There was no capability of even automatically stopping the aperture down to the working stop. Vivitar and Soligor attempted to correct this, with the T-4 system, but it, too has died out completely. Tamron tried to keep the concept of a universal lens mount system alive, with their Adaptall and Adaptall II systems, but I believe that they have stopped making those and are just selling off existing stocks. The original t-mount system is still used for cheap mirror and refracting lenses, such as the 500mm, f/8.0 lenses you see on eBay for $100 new. The t-mount thread is 42mm x 0.75 threads/mm. The M42 (Pentax screw mount) is 42mm x 1.0 tpmm. IOW, t-mount is fine thread; M42 is coarse. You can damage an M42 lens by trying to screw it into a t-mount adapter. Paul Noble

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12-13-2008, 05:43 PM	#2
Ole Administrator Join Date: Sep 2006 Location: Copenhagen, Denmark Photos: Gallery \| Albums Posts: 4,408	This is the one you want, if you want to be able to focus to infinity. It sits flush with the camera mount: Genuine Pentax Screwmount Lens Adapter

12-13-2008, 05:47 PM	#3
KungPOW Veteran Member Join Date: Nov 2007 Location: Vancouver, Canada Photos: Gallery Posts: 1,699	Adapters that have the flange, will always mess with the focus on an M42 lens. The best adapter to get is the genuine Pentax. It fits entirely into the mount, and does not affect the lenses registration distance. I also understand that a "T-adapter" is used to conect a telescope to a pentax camera, and is not intended for an M42 lens. Here is a link to Hin's info about the Pentax adapter: Genuine Pentax M42 to K Adapter - Hin's Tech Corner

12-13-2008, 05:54 PM	#4
winglik Senior Member Join Date: Oct 2008 Location: NYC Posts: 258 Original Poster	Thanx for reply. That means the B&H guy gave me the wrong info. That guy mislead me that T-adapter is same as M42 Screw adapter. But i searched "M42 adapter" on B&H site, and they all show up the same adapter. see link below. So does that mean B&H is wrong on M42 adapter? http://www.bhphotovideo.com/c/product/276088-REG/Kowa_TSPK_A_T_Mount_SLR_Camera_Adapter.html

12-13-2008, 06:12 PM	#5
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	Originally posted by winglik Thanx for reply. That means the B&H guy gave me the wrong info. That guy mislead me that T-adapter is same as M42 Screw adapter. But ihttps://www.pentaxforums.com/forums/newreply.php?do=newreply&p=418081 searched "M42 adapter" on B&H site, and they all show up the same adapter. see link below. So is that mean the who B&H is wrong on M42 adapter? Kowa \| T-Mount SLR Camera Adapter for Pentax \| TSPK-A \| B&H The T-mount is 42mm, but not the same as M-42. Different thread pitch. B&H sells an adapter that should work: General Brand \| Pentax-K Body to Universal Lens Adapter \| B&H The official Pentax adapter is better: PentaxWebstore Mount Adapter B (35mm Screwmount to Bayonet) Good luck! Steve (BTW, I hope you did not damage the threads on any of your M-42 lenses trying to screw them into the T-mount...)

12-13-2008, 06:24 PM	#6
winglik Senior Member Join Date: Oct 2008 Location: NYC Posts: 258 Original Poster	Thank you for clearing that up. If the guy on B&H is knowledge enough, i wouldn't have all these trouble. Another lesson. Thanx

12-15-2008, 10:05 AM	#7
henryp B&H Photo Representative Join Date: Jul 2007 Location: New York, NY Posts: 491	Originally posted by winglik Thanx for reply. That means the B&H guy gave me the wrong info. That guy mislead me that T-adapter is same as M42 Screw adapter. Apparently our sales associate made a mistake. I am sorry he did and if I could ID you or this transaction (which I cannot) I'd be happy to review this with him and his sales manager. I do not believe it was his intent to mislead you. Rather, he made a mistake. Nevertheless, I apologize. I am sure customer service will be happy to help you make the appropriate exchange.

12-15-2008, 11:51 AM	#8
Mike Cash Veteran Member Join Date: Jan 2007 Location: Japan Photos: Gallery Posts: 6,950	Originally posted by henryp Apparently our sales associate made a mistake. I am sorry he did and if I could ID you or this transaction (which I cannot) I'd be happy to review this with him and his sales manager. I do not believe it was his intent to mislead you. Rather, he made a mistake. Nevertheless, I apologize. I am sure customer service will be happy to help you make the appropriate exchange. It would be really nice if B&H offered to compensate him for any damage done to his lens mount due to their error.

12-16-2008, 03:47 AM	#10
winglik Senior Member Join Date: Oct 2008 Location: NYC Posts: 258 Original Poster	Originally posted by henryp Apparently our sales associate made a mistake. I am sorry he did and if I could ID you or this transaction (which I cannot) I'd be happy to review this with him and his sales manager. I do not believe it was his intent to mislead you. Rather, he made a mistake. Nevertheless, I apologize. I am sure customer service will be happy to help you make the appropriate exchange. Thanx, Maybe it just a little mixed up by the salesperson. I know B&H is a pro store when it comes to camera. but anyway. Thanx all your help. I learned a lot from all of you.

12-16-2008, 04:47 AM	#11
titrisol Pentaxian Join Date: Dec 2007 Location: In the most populated state... state of denial Photos: Gallery \| Albums Posts: 1,852	T-mounts were sort of a universal mount pushed by the 3rd parties manufacturers. The screw is also 42mm but the thread is different so M42 lenses will only screw partly. There are still some T lenses and slide copiers for sale, even new so the adapter maybe very useful, keep it. There are adapters for Pentax, nikon, Canon, Minolta, etc etc etc and the T-mount lenses are quite cheap in eekPay

12-16-2008, 06:24 AM	#12
Douglas_of_Sweden Site Supporter Join Date: Apr 2008 Location: Stockholm Photos: Gallery Posts: 3,374	Originally posted by winglik Thanx, Maybe it just a little mixed up by the salesperson. I know B&H is a pro store when it comes to camera. but anyway. Thanx all your help. I learned a lot from all of you. In any case, check the threads on the m42 lenses where you tried the T adapter. You can damage the threads this way, and you may not notice the problem until you later try to mount a correct m42 adapter. If this is the case, you should be compensated, if you ask me.