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03-07-2013, 07:48 PM   #1
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35mm Flektogon f/2.4 Carl Zeiss - Lens Won't Focus at Infinity

This is the lens in question: Carl Zeiss 35mm F2.4 Flektogon MC Lens Reviews - Carl Zeiss Lenses - Pentax Lens Review Database

Does anyone know how to operate on a lens of this type in order to adjust it so it will focus at infinity? This one is not doing it. Or perhaps one of you knows someone else who might know more about doing such a job? Right now it basically will only focus at macro distances. I think it is probably a good lens (well I'm hoping it still is), maybe just needing some internal adjustment?

Thanks for any input or tips!

Last edited by bigrex; 03-07-2013 at 08:23 PM.
03-07-2013, 08:36 PM   #2
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This is an M42 lens, usable on Pentax bodies via an adapter.

There are two different adapters; one that will allow infinity focus and one that will not.

Something like this will not allow infinity focus because there is a piece of metal between the camera body and rear or the lens. I assume this is the type of adapter that you're using? ---> New M42 Lens to PK Pentax for Pentax KM K M K 7 K x K2000 K20D Adapter Ring | eBay

An "infinity adapter", such as the original Pentax branded one, fits inside the camera mount and nothing protrudes outside and gets in the way between
the camera and lens ---> Genuine Pentax M42 K Mount Converter Adapter Japan Nice | eBay

The best way to go is to buy a Genuine Pentax M42 to K Adapter. There are cheaper Asian knock-offs of infinity adapters, but many times, they fit a little too tight or a little too loose. Save yourself the haste and stress by investing in the real deal.

*** The Ebay listings that I posed were just to show picture examples of what the adapter I was talking about looks like; the Genuine Pentax adapter can usually be picked up cheaper ***
03-07-2013, 09:52 PM   #3
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As the previous post indicated it is the M42 adapter that is most likely causing your problem. Take a look at this video....Pay particular attention to how the Pentax M42 / K mount adapter fits inside the barrel of the camera's mount, so that the lens when mounted fits flush to the camera body's mounting ring. Quite a few of the other third party M42 / K adapters have some metal that protrudes out of the camera's mount. This additional metal adds to the lens's registration distance, so that the lens is mounted slightly farther away from the sensor. This elongates the registration distance, and thus does not permit the lens to focus to infinity.

Also, here is another set of links...
hope that helps....


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