Nikon F standard prism, odd fault

Discussion in 'Classic Manual Cameras' started by toni_nikkanen, Oct 22, 2012.

  1. Hello,
    I have a Nikon F standard prism with an odd fault in it. I was wondering what is it? Fungus? A crack? Some kind of separation of cemented elements? It's hard to take a picture of it, but what I can say is that the fault is "3-dimensional"; that is, it looks like it's inside the glass prism itself...
    [​IMG][​IMG]
     
  2. I believe that it is caused by damage to the silvering on the top angle of the prism, there is nothing that can be done short of having it re-silvered.
     
  3. Ok... having a faulty item like this in my shelf bothers me, I wonder if anyone would pay something for a damaged Nikon F standard prism... maybe I should try my luck on eBay? :)
     
  4. Non working Photomic prisms are fairly cheap, and I believe the actual prism part is interchangeable.
     
  5. I have also heard that Photomic prisms can be used on the plain finder. It might be worth finding one. It's getting harder to find a Photomic prism that has no desilvering damage, but it is usually just a couple of smudges like fingerprints on the left and right of the image. These are caused by silver damage under the rubber covered feet that hold the prism down. Whatever you do when changing prisms, don't pry those rubber pads off.
    I'd be more inclined to hunt down a dead meter finder and do the transplant than to let a standard prism go. Good ones are worth a buck or two.
    Your prism looks as if it has desilvered right at the top edge, possibly from impact. I had a Miranda like that, which had been dropped. It looked just as if a big Mayfly had gotten inside the glass.
     
  6. The Photomic prism has another smaller prism glued to it that has to be removed before it will fit. I have done it by crunching it with a pair of pincers. Fortunately it does not seem to affect the silvering in that spot.
     
  7. Photomic finders turn the F into a top-heavy beast to handle. But they do look distinctive, so for shelf display, go ahead and buy a Photomic. There are 4 different ones to choose from:
    http://www.mir.com.my/michaeliu/cameras/nikonf/ffinders/fmeterprism.htm
    If your F originally came with the standard prism and was made prior to 1966, then it would either have to be a "red dot" model or previously sent to Nikon for the mod to accept the Photomic T, FT, or FTN finders.
     
  8. I have a Photomic FTn finder which needs adjustment for current batteries (under-exposes by about 2 stops in a consistent way). I could cannibalize it for the prism and put it into the standard finder, but as I already have a nearly perfect standard finder that I use regularly I think my time will be better spent by getting rid of the problematic finders :)
     
  9. Toni, I would certainly not cannibalize a working FTn finder, which is actually a pretty decent piece of equpment. If you look around on the net you should find the instructions on how to recalibrate this for silver oxide cells.
    Here's one useful page that tells you how. I used this procedure. I set the camera on a tripod aimed at a consistently lit blank surface, and for a reference used a known-accurate Minolta camera with the same focal length lens. The results were very good. All you need for this is a very sharp knife to peel the leatherette off the top of the finder, and a small screwdriver. Alene's Tacky Glue sold in craft stores works very nicely for reattaching leatherette firmly but in a way that can come off again, without any damage.
    Unmetered prisms are valuable enough that if you don't need it you can probably find someone to do the transplant.
     
  10. Matthew, thanks for the tip! Sounds reasonably easy to adjust, so I'll do it. But I think you forgot to add the actual link to the web page you mentioned :)
     
  11. Photomic finders turn the F into a top-heavy beast to handle.​
    Maybe it's because all my Nikon F cameras came to me with Photomic FTn finders and I never knew any other configuration but I never found the weight or balance unwieldy. YMMV of course. Now, add the F36 motor and that's a wrist-cracking beast. :)
    Henry Posner
    B&H Photo-Video
     
  12. I did forget the link, didn't I?
    This PDF can be found in a couple of different places, but here is one version:
    http://cameraobscura.zenfolio.com/photomic_ftnadjustments.pdf

    The third page gives you the adjusment information.
    By the way, I basically agree with Henry above. All my F's have been Photomics until fairly recently, and I never minded them or found them unwieldy. That said, there's no argument that the plain prism is prettier. An all-black one is just grand even when it's worn to a nub.
     
  13. The OP's prism may have been dropped, and the top of the prism chipped. The prism I regularly use is this way, and it is easier to tolerate it than to try to swap prisms from a FTN finder.
     
  14. This is a camera to be used and used and used, until they quit making film. When the meter in the photomic prism in my F quit, I got a standard prism off of KEH for a reasonable price, which gave it a balance that I like from using fm2's all my life. If I forget my light meter the sunny 16's never let me down. And the photomic heads for the F can't meter with a lens that doesn't have rabbit ears too.
     
  15. Is it OK to put blatant advertisements in the form of eBay links here? :)
     
  16. eBay links here​
    Nope.
     

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