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  1. #1
    pellicle's Avatar
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    how to fix Bessa RF focus problems (swing)

    Hi

    I recently bought a Bessar RF to dabble in what this sort of camera can do. It has been both a revelation and a frustration. My problem is uniform focus across the image. The lens seems to swing a little to one side (probably as a result of the design that allows it to fold ;-) ) . There is some play there, but it fells much less than a degree of movement. I'm used to movements with my 4x5 camera and given that I use a 90mm lens (not unlike the 105 Skopar on the Bessar) I don't think this amount of 'free play' is enough to account for what I'm seeing.

    For example, with this image



    it seems that focus is just 'poor' at the edges, however close examination shows that its actually a tilt ofthe focal plane (camera in portrait orientation).

    Looking at the top right in more detail a pine tree quite further back which is in focus while the pine needles of "my tree" are starting to fuzz up badly.



    Looking at the middle of the focal plane the "my tree" is in focus, but the middle of that pine tree above is out of focus (consistent with the DoF created with f8).



    then looking further to the bottom its apparent that the focal plane is comming closer to the camera



    While this has some advantages in some orientations, I think I would prefer to have the focal plane at a more predictable and "normal" orientation.

    So, does anyone have any suggestions on how to fix this? I'm having trouble seeing this effect on a ground glass and loupe I made up, so this will make 'adjustment' tedious.

    Aside from that, its a nice camera!
    Theory: you understand why it should work but it doesn't
    Practice: it works but you have no idea how
    Here theory and practice meet, things don't work and I don't know why
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  2. #2
    Anupam Basu's Avatar
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    Your lens shouldn't be wiggling about - certainly not enough to have mini view camera movements . Try with another lens to see if the problem is fixed.

  3. #3
    pellicle's Avatar
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    Hi

    Quote Originally Posted by Anupam Basu View Post
    Your lens shouldn't be wiggling about - certainly not enough to have mini view camera movements . Try with another lens to see if the problem is fixed.
    the bessa RF does not have interchangable lenses. Certainly with the right tools they can be removed, but I don't happen to have one spare.

    To be perhaps more clear about this camera its a Voigtlander Bessa RF which is a 120 roll film 6x9 folder.

    pardon me for not making that clearer earlier
    Theory: you understand why it should work but it doesn't
    Practice: it works but you have no idea how
    Here theory and practice meet, things don't work and I don't know why
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  4. #4
    JPD
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    I had the same problem with an Ensign Selfix 820 camera, and solved it by tightening the shutter retaining ring inside the camera.

  5. #5
    pellicle's Avatar
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    Hi

    Quote Originally Posted by JPD View Post
    I had the same problem with an Ensign Selfix 820 camera, and solved it by tightening the shutter retaining ring inside the camera.
    ok ... but the shutter / lens assembly is tight, I'm sure that its the metal base that it is mounted to. Still, I'm not sure its the 'play' that is the problem. I think its mis-aligned.
    Theory: you understand why it should work but it doesn't
    Practice: it works but you have no idea how
    Here theory and practice meet, things don't work and I don't know why
    Homepages: here Blog: here

  6. #6
    Jim Noel's Avatar
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    I think you are correct in assuming that the camera is out of alignment. I don't know the camera well enough to suggest a cure.
    [FONT=Comic Sans MS]Films NOT Dead - Just getting fixed![/FONT]

  7. #7
    JPD
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    The lens/shutter sits very rigid in place on my RF-Bessa, with no play at all. Check the camera shutter assembly and standard carefully to find out if something is bent. On both sides of the shutter assembly there are slightly rounded metal stops that are there to hold the lens and shutter rigid.

    I hope you know what I mean. My english is limited, but better than my finnish even though we are neighbors.
    Attached Thumbnails Attached Thumbnails rfbessa.jpg  

  8. #8
    pellicle's Avatar
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    Hi

    Quote Originally Posted by JPD View Post
    The lens/shutter sits very rigid in place on my RF-Bessa, with no play at all. Check the camera shutter assembly and standard carefully to find out if something is bent. On both sides of the shutter assembly there are slightly rounded metal stops that are there to hold the lens and shutter rigid.
    yep (looked at images, thanks for that) thats the spot. I can feel some free play in that whole 'plate / mount' on the end of the bellows. Perhaps a mm or maybe less. I don't think its enough to cause the alignment issue I'm seeing, but it might be.

    I have tried another method of putting the camera open on a flat and level surface and placed level across the lens (metal front rim). It is definately not level. perhaps an entire degree or maybe two.

    I bought the camera from a fellow called certo6 who is highly recommended. Certainly the camera is otherwise in perfect operational order and looks very neat for its age. Still I did pay rather a high sum for it (I consider that I paid for his time and effort in service not the camera really).


    Quote Originally Posted by JPD View Post
    I hope you know what I mean. My english is limited, but better than my finnish even though we are neighbors.
    no problems. I'm acutally a 'moved in' neighbour. I'm Australian

    :-)

    sina ruotsilianen ja mina australialianen koska australialianen minunkin suomi on paska.
    Theory: you understand why it should work but it doesn't
    Practice: it works but you have no idea how
    Here theory and practice meet, things don't work and I don't know why
    Homepages: here Blog: here

  9. #9
    JPD
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    Quote Originally Posted by pellicle View Post
    I bought the camera from a fellow called certo6 who is highly recommended.
    Can't you send it back? I thought Jürgen Kreckel had some sort of warranty on the cameras he sell.


    no problems. I'm acutally a 'moved in' neighbour. I'm Australian

    :-)

    sina ruotsilianen ja mina australialianen koska australialianen minunkin suomi on paska.
    Ah, that explains your "-our" endings of words.

    Sinä oh... uh... makkara.

  10. #10
    pellicle's Avatar
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    Hi

    Quote Originally Posted by JPD View Post
    Can't you send it back? I thought Jürgen Kreckel had some sort of warranty on the cameras he sell.
    I suppose I could always try, but:
    • on what grounds (it does operate well)
    • its not exactly cheap to post to and from the USA
    • I've already contacted him and he didn't think there was much to see in the images
    • one may aruge that he is not selling new cameras only refurbing them as best as possible
    • people may consider this acceptable



    Quote Originally Posted by JPD View Post
    Ah, that explains your "-our" endings of words.

    Sinä oh... uh... makkara.
    such as? I don't recall typing colour and the other words are spelt the same way in both English (as used by British, Canadians and Australians) and American (as used by Americans Koreans and Japanese).

    ;-)
    Theory: you understand why it should work but it doesn't
    Practice: it works but you have no idea how
    Here theory and practice meet, things don't work and I don't know why
    Homepages: here Blog: here

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