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M42 Lenses on K-3 ?


Brian Wells

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what happend to the aperture ring? is stucked?

Some lenses have a "pin" near the lens mount that must be "pushed-IN" to activate the iris function.

 

The problem is the K-3 lacks the mechanism to "push" the pin inside the lens. So, turning the aperture ring does not affect iris. Peleng does not have such a "pin" but every other M42 mount lens I have tried does.

 

How can I modify an M42 lens to work on the K3, short of using adhesive to hold in the pin?

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You want to look for M42 mount lenses that have an "Auto" & "Manual" aperture switch like the Pentax Super Takumar lenses. That will allow you to set it to manual and move the aperture ring as needed.

 

The other way around it is to take a paperclip and jam in the little pin that allows control of the iris by a camera. Once you do this however, the auto function won't work on a 35mm camera if you care. I did this on my 8mm Peleng I think.

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Some lenses have a "pin" near the lens mount that must be "pushed-IN" to activate the iris function.

How can I modify an M42 lens to work on the K3, short of using adhesive to hold in the pin?

Many of the lenses have a little switch that says A M , in the M position the pin is not used. - some of them require pushing a tiny pin in to unlock the switch..If you have a lens that does not have the "manual"switch I wonder if you could rig soemthing in the lens mount?

 

The pin is suposed to stop the lens down at the instant of exposure and let it come open after the shot on a still camera, a feture that is useless on a movie camera.

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Many M42 lenses have a M->A switch, your lens needs to have this switch to be use-able in more than wide-open mode on a K-3.

 

Also some lenses have an additional Lock Pin, those will be out of focus on the K-3.

 

Here is what a Manual/Auto switch looks like on a lens.

 

 

Manual.

P1000461.jpg

 

Auto.

P1000462.jpg

 

When in manual mode, the aperture pin will go down, and become in-active, if this does not happen, your lens is broken.

Edited by Dennis Kisilyov
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When in manual mode, the aperture pin will go down, and become in-active, if this does not happen, your lens is broken.

 

Err... actually the pin gneeraly does not move but the Diaphram does stop down to the appature the lens is set to., in manual the pin has not effect.

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Err... actually the pin gneeraly does not move but the Diaphram does stop down to the appature the lens is set to., in manual the pin has not effect.

 

Out of 45 lenses with pins that I have, the aperture PIN will drop down as the spring holding it out will dis-engage (the pin is in free motion), you can see this from the photos I've posted.

The times it did not I had a dysfunctional lens aperture mechanism.

 

Also the M-A switch can be caught by the aperture ring that is close to the lens (another dysfunction), and engage AUTO during filming.

 

EDIT:

 

Actually the PIN being stuck is a chief complaint about these lenses on SLR's, that means during exposure the PIN fails to engage the aperture in time. Thence it needs to be fairly loose.

Edited by Dennis Kisilyov
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Guest Ole Dost

Try M42 lenses that have been built beyond the iron curtain. The camera brand "Praktika" from "Pentacon" Dresden / GDR was bulit longtime with a M42 Mount and some really great lenses have been produced for these Cameras, lenses between 24 and 500mm. The Pentacon 1:1,8 50mm Standard lens (which is telefoto for 16mm, of course) is the best lens for 50mm I ever used on my 35mm Still Cameras. Far better then the 1:1,2 and 1:1,8 50mm lenses from Canon, that I have been using too. The Pentacon 50mm lens fits perfectly to my Krasnogorsk and there is no problem closing or opening the aparture when mounted on my Krasnogorsk.

You can get Pentacon M42-lenses easily on EBay -especially EBay Germany (www.ebay.de)

Best regards,

Ole

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