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10-05-2016, 07:27 AM   #1
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Pentax Adapter K for 645 Lens (645 to K mount) Read more at: http://www.pentaxforums

Who can tell may my K-1 work with 645 lenses using Pentax Adapter K for 645 Lens (645 to K mount)...?

Thank you !

Nick Uplander

10-05-2016, 07:48 AM   #2

Join Date: Sep 2011
Location: Richland, Washington, USA
Posts: 876
Well, I have the adapter, mounted it to my 645 400mm, tried to mount to my K-1 and wound up scratching the paint on the camera body because the screw ( I assume it's some sort of locking screw) on the adapter didn't clear the camera body at the prism. Maybe the screw could be removed but proceed with caution.
10-05-2016, 08:57 AM   #3
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I believe the adapter allows you to rotate the mount so that the screw is on a different part of the mount, and therefore will not contact the overhanging pentaprism area.
10-05-2016, 08:59 AM   #4
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Join Date: Feb 2012
Posts: 122
I've been using a Mamiya 645 Lens to K-mount adapter - that works as intended. There's no magic and no rocket science involved, and it's totally ununderstandable how such a beast (albeit for Pentax 645 instead of Mamiya 645 mount) should scratch a camera. The rear end (that's the one that goes into the K-1) is identical between these two.

There's one little caveat. Should you be using the adapter in conjunction with Pentax's 1.7x AF teleconverter, you should ascertain that the adapter is electrically conductive. If not, the camera doesn't detect a lens mounted to the teleconverter and the AF won't operate.

10-05-2016, 09:40 AM - 1 Like   #5
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Join Date: Nov 2015
Location: California
Posts: 222
Ive used the adapter and it works well. There are a few things to note. The adapter spins so that the screw on it will not hit the pentiprism as leekil mentions. Also the lens needs an aperture ring so lenses such as the dfa 55 will not work.

10-05-2016, 11:41 AM - 1 Like   #6
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QuoteOriginally posted by Uplander Quote
Who can tell may my K-1 work with 645 lenses using Pentax Adapter K for 645 Lens (645 to K mount)...?

Thank you !

Nick Uplander
It is also possible to use a MIREX tilt/shift adapter for Pentax 645 lenses instead of the original Pentax 645 Adapter (MIREX-Adapter f). The current version did fit to all APS-C Pentax Cameras but not to the K-1.
A new version is under development.

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