How to disassemble a Zeiss Sonnar 5cm f2 collapsible anyone?

Discussion in '35mm Cameras and Accessories' started by IloveTLRs, Mar 25, 2015.

  1. IloveTLRs

    IloveTLRs Member

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    I have a Sonnar 50mm collapsible with very noticeable haze, which shoots very soft at f2. From a 1930s brochure I have, here is a cut-away diagram of what the lens looks like:

    [​IMG]

    The rear elements come out very easily, but it appears that the rear surface of the front element has the haze. (At least, I'm hoping it's not the cemented elements.) Does anyone know how to get into the lens any further?
     
  2. antmar

    antmar Member

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    Please don't damage this rare piece of glass, leave the cleaning to a well experienced repairman. Many old lenses that are on evil-Bay have poor performance because of a previous amateur service attempt. These lenses come and go from one owner to the other, I would prefer some haze than a bad assembly.
     
  3. baachitraka

    baachitraka Member
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    Do not it by yourself please. Like antmar said please send it to a well know repair shop. It may need a an optical bench for collimation...
     
  4. OP
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    IloveTLRs

    IloveTLRs Member

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    Is there someone - preferably in Europe - who wouldn't charge a fortune to clean it? If there is inner-element haze (between cemented elements) then it's a write-off to me.
     
  5. baachitraka

    baachitraka Member
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  6. Nr90

    Nr90 Member

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  7. richardHaw

    richardHaw Member

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    Sorry, I may be too late for this. I am in the middle of overhauling the same lens.
    I may write an article for this one of these days in my richardhaw.com repair blog.

    1: basically, remove the smaller screw you find under the mount collar and unscrew the front part of the lens off.

    2: remove the screw off from the ring that holds the aperture ring and then unscrew that off

    3: the front ring also has a screw and should also be unscrewed

    4: at this point, the front elements are free as nothing is holding it

    5: the rear elements can be unscrewed from the housing. you will need a lens spanner of you want to go deeper

    6: remove the screw from the iris cup and the cup should come off after you remove its retainer ring which is secured by another screw

    7: the iris assembly is secured with a C-ring

    this is a condensed guide. sorry, no pictures yet
     
  8. Trask

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    RichardHaw -- I do hope you can put up some pictures. I have a collapsible Sonnar (that I paid all of $50 for) that has what appears to be brown lubricant on the blades, which at a minimum should be addressed. Given my investment in the lens I could see taking a shot at repairing it myself, which your online pictures as guidance.
     
  9. richardHaw

    richardHaw Member

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    i do not know when I can make one in my richardhaw.com repair blog. but I will in the future. You will need some very good drivers for this.
     
  10. richardHaw

    richardHaw Member

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    mine had plenty of grease. an unbelievable amount
     
  11. Trask

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    I'll get some good drivers, not a problem. Interesting yours had lot of lube too.
     
  12. E. von Hoegh

    E. von Hoegh Member
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    I recently cleaned one that I have very good reason to believe had never been apart. You will need drivers with relatively thick blades for their width, in these cases I use
     
  13. Trask

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    what? In these cases you use what? Inquiring minds want to know!
     
  14. Cine 35

    Cine 35 Member
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    Rick Oleson has a set of notes for sale (well worth the $25 cost for entertainment value alone) for many cameras and lenses, including the collapsible Sonnar. It gives step by step disassembly instructions with drawings. Keep in mind, however, that it does not include fine details and does not tell you how to reassemble it. Based on experience with the P6 Sonnar 180mm, getting the aperture back together can be tricky, but patience and mechanical aptitude can get you there.

    http://rick_oleson.tripod.com/index-27.html
     
  15. E. von Hoegh

    E. von Hoegh Member
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    Argh. I have no clue what happened to that post.
    Here goes.
    ...#6 Swiss needle files to fit the screwdriver blade precisely to the slot. Aim for a hollow profile with the part of the blade entering the slot square and parallel.Use a loupe to be certain. When selecting screwdrivers make certain they are hard, when a soft blade twists in a headless screw (grubscrew) it often spreads the slot, wedging the screw tighter than ever. The screwdriver blade should be just soft enough to touch with a file.
    Putting a dab of lacquer thinner on the screw often loosens stuck screws.
    The screws in the aperture ring must be accurately reoriented over their original locations, so they seat in their little depressions in the aperture sleeve. The ring which retains the aperture sleeve is also the part the lens seats on in the mount, it must go back precisely as it was. Use solvent on this, too, it can be stuck after 80 or so years.

    The screw which locks the optics capsule in the mount is a grubscrew located a bit up from the rear of the mount barrel, the two flathead screws at the rear of the barrel don't need to be touched.
     
  16. Trask

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    Thank you. E. von Hoegh -- very useful, as are Cine 35 comments about Rick Oleson's notes. Adventures lie ahead...
    s
     
  17. E. von Hoegh

    E. von Hoegh Member
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    Good luck, these are really nice lenses when cleaned up.
    Be careful to check for grubscrews whenever trying to loosen something, just about every threaded ring and retainer has one. For some reason the Germans and the English both love grubscrews.
     
  18. Cine 35

    Cine 35 Member
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    Two other thoughts: First, have a roll of scotch tape and a piece of 8.5x11 paper and tape each part down on the paper and label it as you remove it. Second, take a photo before removing each screw or piece so you have a reference when reassembling.
     
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