Pentax 645 and 6X7 or 67 lenses to PK

Adk X · 04-23-2012, 09:51 AM

What do I need to mount a 6x7 lens to a PK mount..same thing for a 645 lens to a Pk mount....I see alot of nice old lenses out there that should go on my K-5 but don't know how to go about it . ALSO will an old threaded Takumar lens go on my K-5 ? You guys a a big help to a beginner......Thanks !!

desertscape · 04-23-2012, 10:12 AM

There are adapters available for what you are attempting to do, however it should be noted that the 6x7 and 645 lenses are hard pressed to match the performance of Pentax's smaller format lenses. If you are serious about doing this, research which lenses are in the top tier for 645 and 6x7.

tuco · 04-23-2012, 10:48 AM

Yes, why? In the case of a 67 lenses, you'll have stopped down metering and a large, bulky lens. In the film days, medium format lenses did not need to be designed with as high MTF compared to what is needed on the smaller format.

RioRico · 04-23-2012, 01:39 PM

Originally posted by Adk X

ALSO will an old threaded Takumar lens go on my K-5 ?

Yes. You'll need an M42-PK adapter. If you only have one M42 (threaded) lens, and will only have very few, then a single Official Pentax adapter is just right for you. I've seen at least one in the Marketplace here in the last couple days. Cheers!

**slip** · 04-23-2012, 04:29 PM

I could have gotten a great deal on 2 645 lenes until I found out the price of the adaptor (I think it was around the 200 dollar range when I last looked) then I told myself to forget about it

Adk X · 04-23-2012, 07:33 PM

I've got a couple original screwmount to PK adapters....So you are saying that the 645 and 6x7 are the same mounting as the Takumars ??

**slip** · 04-24-2012, 05:21 AM

Originally posted by Adk X

I've got a couple original screwmount to PK adapters....So you are saying that the 645 and 6x7 are the same mounting as the Takumars ??

I could be wrong but the newer 645 lenses are not likely screw mount

tuco · 04-24-2012, 07:15 AM

Pentax 6x7 and 645 lenses are not screw mount. You need an adapter for each format to fit your 135 format K-mount.

Adk X · 04-25-2012, 03:24 PM

Thank you Tuco ....will have to bone-up on what adapters are good and what ones are not-so-good ! Any suggestions ?

04-23-2012, 09:51 AM	#1
Adk X Junior Member Join Date: Jan 2011 Location: Adirondack Mts. Posts: 44	Pentax 645 and 6X7 or 67 lenses to PK What do I need to mount a 6x7 lens to a PK mount..same thing for a 645 lens to a Pk mount....I see alot of nice old lenses out there that should go on my K-5 but don't know how to go about it . ALSO will an old threaded Takumar lens go on my K-5 ? You guys a a big help to a beginner......Thanks !!

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04-23-2012, 10:12 AM	#2
desertscape Pentaxian Join Date: Feb 2009 Location: Arizona Posts: 1,007	There are adapters available for what you are attempting to do, however it should be noted that the 6x7 and 645 lenses are hard pressed to match the performance of Pentax's smaller format lenses. If you are serious about doing this, research which lenses are in the top tier for 645 and 6x7.

04-23-2012, 10:48 AM	#3
tuco Pentaxian Join Date: Jul 2009 Location: Seattle Posts: 7,611	Yes, why? In the case of a 67 lenses, you'll have stopped down metering and a large, bulky lens. In the film days, medium format lenses did not need to be designed with as high MTF compared to what is needed on the smaller format.

04-23-2012, 01:39 PM	#4
RioRico Veteran Member Join Date: Jun 2008 Location: Limbo, California Posts: 11,264	Originally posted by Adk X ALSO will an old threaded Takumar lens go on my K-5 ? Yes. You'll need an M42-PK adapter. If you only have one M42 (threaded) lens, and will only have very few, then a single Official Pentax adapter is just right for you. I've seen at least one in the Marketplace here in the last couple days. Cheers!

04-23-2012, 04:29 PM	#5
slip Site Supporter Join Date: Oct 2006 Location: 2 hours north of toronto ontario canada Photos: Gallery \| Albums Posts: 3,537	I could have gotten a great deal on 2 645 lenes until I found out the price of the adaptor (I think it was around the 200 dollar range when I last looked) then I told myself to forget about it

04-23-2012, 07:33 PM	#6
Adk X Junior Member Join Date: Jan 2011 Location: Adirondack Mts. Posts: 44 Original Poster	I've got a couple original screwmount to PK adapters....So you are saying that the 645 and 6x7 are the same mounting as the Takumars ??

04-24-2012, 05:21 AM	#7
slip Site Supporter Join Date: Oct 2006 Location: 2 hours north of toronto ontario canada Photos: Gallery \| Albums Posts: 3,537	Originally posted by Adk X I've got a couple original screwmount to PK adapters....So you are saying that the 645 and 6x7 are the same mounting as the Takumars ?? I could be wrong but the newer 645 lenses are not likely screw mount

04-24-2012, 07:15 AM	#8
tuco Pentaxian Join Date: Jul 2009 Location: Seattle Posts: 7,611	Pentax 6x7 and 645 lenses are not screw mount. You need an adapter for each format to fit your 135 format K-mount.

04-25-2012, 03:24 PM	#9
Adk X Junior Member Join Date: Jan 2011 Location: Adirondack Mts. Posts: 44 Original Poster	Thank you Tuco ....will have to bone-up on what adapters are good and what ones are not-so-good ! Any suggestions ?