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Thread: Pentax 20-40 Auto 110 zoom

  1. #1
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    Pentax 20-40 Auto 110 zoom

    I picked up a BGN condition example of this lens from KEH the other day, and intend to use it with Jin Rong's new adapter. I couldn't resist--it was cheap, is an f/2.8 zoom (!), and according to CameraQuest was made with an aspherical element. It seems like a nifty curiosity.

    Anyway, I wonder if anyone else has tried it on m4/3. If not, I'll run some tests when it and the adapter arrive.

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    Re: Pentax 20-40 Auto 110 zoom

    Here's a picture from someone's flickr (click for link):



    Looks like it will actually be a perfect size for the GF1!

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    Re: Pentax 20-40 Auto 110 zoom

    It's a nice package on the GF1 too. Indeed it has an aspherical. for a hood I use the 49mm Minolta hood they made for the 45/2 pancakish SLR lens. Mine is now married to m39 threads, combined with Jin's m39-m4/3 adapter. The lens is way too big for the tiny mount. I intend to graft some kind of aperture cap on the still accessible bayonet.
    Still have to test and compare to other lenses.
    "You live and learn; at any rate you live" (Douglas Adams)

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    Re: Pentax 20-40 Auto 110 zoom

    Quote Originally Posted by laptoprob View Post
    It's a nice package on the GF1 too. Indeed it has an aspherical. for a hood I use the 49mm Minolta hood they made for the 45/2 pancakish SLR lens. Mine is now married to m39 threads, combined with Jin's m39-m4/3 adapter. The lens is way too big for the tiny mount. I intend to graft some kind of aperture cap on the still accessible bayonet.
    Still have to test and compare to other lenses.
    Would love to see a pic of it on the GF1, as well. And where did you get the M39 adapter?

  5. #5
    duckrider
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    Re: Pentax 20-40 Auto 110 zoom

    She's a FAT lady!

    In opposition to the other 110 lenses (including the 70mm) the zoom is not that small.
    Got my Petax outfit for little money two days ago, now I'm waiting for the ordered adapter.
    Hope it will come next week.
    have fun
    Thomas

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    Re: Pentax 20-40 Auto 110 zoom

    Quote Originally Posted by mabelsound View Post
    Would love to see a pic of it on the GF1, as well. And where did you get the M39 adapter?
    The lens is glued to m39 threads, screwed to a chinese m39-m4/3 adapter.
    I have a Minolta hood on it (from the 45/2 MD lens).

    http://e-p1.net/MGalleryItem.php?id=380
    Last edited by laptoprob; 5th February 2010 at 02:14. Reason: pic hassle
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    Re: Pentax 20-40 Auto 110 zoom

    Quote Originally Posted by laptoprob View Post
    The lens is glued to m39 threads, screwed to a chinese m39-m4/3 adapter.
    I have a Minolta hood on it (from the 45/2 MD lens).

    http://e-p1.net/MGalleryItem.php?id=380
    Still can't see the pics, but it seems to me that this is a superb way to get the lens onto an m4/3 camera--I just did this myself with an m39 mount I had lying around and some Loctite Weld...let's see if it holds. The nice thing here is that the mount is larger, there's no light leak, and you can shim to get infinity. The m39 thread is easy to center on the lens, too--it's just a little larger than the 110 lens mount already on there. And yes, if I can find some extra rear caps, it should be a cinch to make some different-sized apertures.

    The 70mm is a less good candidate because of the size of the mount end, so I'll wait for my RJ 110 adapter to arrive, to give that one a try.

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    Re: Pentax 20-40 Auto 110 zoom

    OK, in the end, I decided to just epoxy an entire M mount on there--the M39 thread didn't make enough contact with the lens for comfort. It's drying now, so I can't do any serious testing with it, but it fits, it works, it focuses a bit past infinity--just a touch--and punching an aperture hole in the rear cap seems to work great. I sanded down the bottom of it to make sure the edge would be smooth, then used a heavy-duty hole punch for the aperture. I'll go outside with it tomorrow, but some quick tests in the living room are promising. Looks like it might be around f/8?


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    Senior Member pellicle's Avatar
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    Re: Pentax 20-40 Auto 110 zoom

    looks great ... got any samples of it on your camera?

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    Re: Pentax 20-40 Auto 110 zoom

    "You live and learn; at any rate you live" (Douglas Adams)

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    Senior Member m3photo's Avatar
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    Re: Diaphragm

    Quote Originally Posted by mabelsound View Post
    I sanded down the bottom of it to make sure the edge would be smooth, then used a heavy-duty hole punch for the aperture.
    So, out in the street armed with several pre-drilled lens caps and "all" one has to do to change aperture is take the lens off the camera, unscrew one cap, replace it with another, put the lens back on the camera and you're ready for the next shot. Back to the days of the "Speed" Graphic when changing film on the go - sounds fun. Now, where's that magnesium powder for my flash?

    Just kidding and poking fun at myself in the process; I'm a fixed lens shooter with my FF camera, carry around my trusty CV 50mm Nokton for the G1 and have all the 110 lenses ready for their adapter ...

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    Re: Diaphragm

    Quote Originally Posted by m3photo View Post
    So, out in the street armed with several pre-drilled lens caps and "all" one has to do to change aperture is take the lens off the camera, unscrew one cap, replace it with another, put the lens back on the camera and you're ready for the next shot. Back to the days of the "Speed" Graphic when changing film on the go - sounds fun. Now, where's that magnesium powder for my flash?
    That's funny
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    Re: Pentax 20-40 Auto 110 zoom

    Making things difficult for yourself is fun!

    I'll get some pics up later. My M8's in for service, so the GF1 is my only digicam...I gotta take photos of it on film!

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    Re: Pentax 20-40 Auto 110 zoom

    I see the photo of the 39mm threaded mount in my previous post doesn't work.
    "You live and learn; at any rate you live" (Douglas Adams)

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    Re: Pentax 20-40 Auto 110 zoom




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