Need help in disassembling Nikkor 500mm Relfex

Discussion in 'Nikon' started by paul_ong|1, Nov 7, 2009.

  1. Hi,

    I need to disassemble my Reflex-Nikkor C f/8 500mm lens. There are some dust and a couple of small white spots on the interior of the front element that I want to clean. Ideally, I would like to come in from the front.

    Here is what I can see. It appears that the front glass/lens element or elements are held in by two retainer rings. The outer one appears to the held in place by a very, very small screw on the side and does not have any notches for a spanner tool. It appears easy enough to grab these first ring and unscrew it because it is about a half inch deep, that is, after removing the small screw. The inner ring appears to require an spanner tool because I can see the notches below the outer ring.
    Below are two photos to illustrate what I see.

    Larger versions can be accessed at:

    http://www.flickr.com/photos/9476880@N02/;

    Before I start working on this, I would like to get as much advice, suggestions, information, and links to information as possible. Any input would be greatly appreciated.

    I am doing this myself because it is not worth sending it to Nikon service given the monetary value of the lens. I have also tried to find information through a Google search but have not come up with anything.

    Thank you in advance.
    --
    00UwyI-188039584.jpg
     
  2. Second photo. Sorry, could not load both at the same time.
    00UwyO-188039684.jpg
     
  3. Paul, FWIW, I cringe when I hear someone wanting to take apart good equipment, but that could be because I personally always end up with spare parts<g>. Here's why I would not do it with this lens: a) specks on the elements of such a long lens of this design will be obliterated to an non-recognizable form (IOW, I doubt you'd see any effect on the final image). b) The design of a reflector lens, such as this, involves some fairly precise alignment. Mirrors have to align, and when they don't, I can't imagine the effect on image quality. c) My repair shop would probably only charge about $100-125 to do the job right (I don't know what Nikon would charge).
    If you conclude that the lens is unusable or you won't use it in the state it is in, then you have to ask yourself: would you spend $125 for a working version of this lens (ala a competent repair person).
     
  4. Michael,
    Thank you for the advice. For me, it is not worth spending $125 to clean this lens. It is not a great lens and does not have much value in the used market. But it is worth trying to clean, and I love to do little projects like this.
    I am not concerned about the dust, nor any minor scratches. My concern is about the small white circles which could be the start of some fungus growth, which is a big concern for this lens.

    I have a little experience in taking apart and repairing other optical and film equipment, and have had experience with alignment of a 8 inch Celestron schmidt-cassegrain telescope.

    Last night, I was able to remove the two rings without any problems, and have very careful to document (photograph) each step first, and noting initial alignment of the rings. The next step is taking out the front glass element, which I will do next weekend.

    The front element appears to be held in by some white rubbery glue in a couple of spots along the rim only. Before removing the glue completely, I want to see if anyone has an information on it. Below is a photo of the glue, which is at the top of the lens with a small part peeled away.

    A larger version is at
    http://www.flickr.com/photos/9476880@N02/;
    You also notice that there is a fair amount of dust on the inside of the glass element.
    00UxLS-188347584.jpg
     
  5. Curious how you make out. I have the same lens with similar but not as severe problems. Also, I kind of like the shots I get from it, seems grainy like film.
     
  6. Thomas,
    So far so good, but going slowly. Will not have time to work on this until next weekend. Hope to provide an update then.
     
  7. Happy to report success. I had to learn by doing and trail and error, with many mistakes along the way, but I am happy with the results.
    Since I had the day off, I spent part of it working on the 500mm reflex lens. I was not able to remove the front element by taking off the two front retainer rings, so I decided to try to go in from the back. After some slow and careful steps, I was able to remove the rear lens cell and clean the interior side of the front element, as well as other optical parts. While it took me three days to figure this out, it is actually very easy to disassemble the lens once you know the steps, easily in 10-15 minutes. Assembling is just as fast. Also, this method does not tamper with the critical alignments of optical parts.
     
  8. Great job, could you please pm or email (wylu2005@gmail.com) me what are the "steps"?
     

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