Nikon ft3 cds cells same as in ft2?

Discussion in 'Nikon' started by marijanradaljac, Dec 1, 2020.

  1. Hi, this is my first post here so I would like to say hello to everyone first.

    I have FT3 with bad cells. Not gone completely, light-meter is still in working condition but 3-4 stops off (underexposing). I checked wiring, battery compartment, cleaned variable resistor plate and contacts under the mount. Finished with smoothly moving needle but as I said, not accurate one. I tried to replace cells with 2-6kOhm Token PGM5506 cds cells (original ones where marked 6K and that is only thing that ID them - measured with ohm meter originals will be in range from 400ohm facing light bulb and to 1.3kOhm when"closed") and calibrate meter with it`s trimmer, but those new ones overexposed for 3-4 stops, with trimmer in original position. It was simply cheap test.

    10 service shops in Europe declined work on it (...we don`t have spare parts...). One Swiss shop wanted over 200 eur for replacement and calibration. I am not prepared to pay that much. Replacement of the cells is one hour job most ( at least it took that much to me - amateur). Cant say about calibration.

    So I am in search for "for parts" body with hopefully god cds cells. Does anyone know if the cells in FT2 where the same as in ft3 (electrical characteristics) . ft2 is much easier to get than ft3. Anyone had any success finding good modern replacement? Source for a replacement pair? And finaly any ideas beside suny 16 and good lightmeter (I do that now, but I would like to have it repaired).

    Thanks.
    Marijan
     
    Last edited: Dec 1, 2020
  2. Are these better than normal cds cells? :p
     
  3. ShunCheung

    ShunCheung Administrator

    It is hard to say for sure, but the FT3 is almost exactly the same camera as the earlier FT2, except that the FT3 is AI (auto-indexing, not artificial intelligence :cool:) compatible. I bought an FT3 in 1977 when Nikon first introduced AI, and that body was only in production for like two years, since Nikon also introduced the FM in 1977 as an AI body, and there was a lot of overlap between the two. The FM is smaller and carries the Nikon instead of Nikkormat brand name. The shutter speed dial is on top instead of around the mount.
     
  4. Yes, they last forever. But I would take normal ones too.
    Thanks Shun.
    Specifications about the cds cells in the ft2 service manual (I do not have access to the ft3 service manual, which would be helpful to determine if this two cameras share the same cells) isn't really revealing at least not to me.
     
    mike_halliwell likes this.
  5. Both the FT2 and FT3 use a single 1.5v Silver-Oxide cells, you have a good chance of them being the same.

    The FM switched to Gallium Photocells. The FE and EL2 use SPD's.
     
  6. My FT3 also bounces around. Then suddenly it works for a while and then starts jumping again. So I use my Nikon N6006 which is not a great camera supposedly but works flawlessly. The electronic shutter is perfect. I tested it and the speeds are on the money. The metering, functions, etc all work great after thirty years. The zoom lens is not supposed to be good. But I tried it out and got decent results.Link: - Removing ground brush with fire - 35mm Tmax 400 I could use the FT3's 50mm, f/2.0. But it's manual focus and a pain to use in an automatic camera like the N6006.
     
  7. It is a trying game when the parts aren`t exact match to the original specs. And not being careless idiot, but patient and precise instead, does helps too. I accidentally soldered one cds wire "directly" to the switch leaving the resistors out of circuit. It still worked but the reading was much more off.
    After fixing that: I managed to "fix" the meter using one old (better) cell and one new Token one. After some adjustment of the main trimmer pot I am now in the "one stop off" range. If I adjust the camera on 175-200 ISO while reference camera is on 100 I have almost identical results all over the range of apertures and speeds in different lightning situations. I probably will order few more cells, they are cheap and try to get more precise result, but for now this will do. I also found 20$ FT2 donor camera. Will see.
    Thanks for help.
     
    Last edited: Dec 3, 2020
  8. I am pretty sure that the FM uses silicon photodiodes, too, but there are some Nikon publications that say GaAsP.

    The FM has the LED meter display which uses GaAsP, and somehow that got into the description.

    LEDs make less than optimal sensors. The only use I know for LEDs are photodiodes is in optical
    communication (for hobbiests) where aligning in one direction aligns both directions.

    Since the FT3 was, at least considered by me, practice for the FM, I would have thought it would use
    the same sensor, but it seems only practice at AI metering.

    I got an FM not so long after they came out, an FT3 (used) only a few years ago.
     
  9. There are GaAsP, photodiode which are used as light sensor.
     
  10. The FM2 and FM2n, as well as FE and FE2, use SPD's.

    The FM, Konica FS-1, and Pentax MX use Gallium Arsenide Phosphade (made me look up the "P"). I'm more used to Indium Gallium Arsenide (InGaAs) based photocells..

    SPD's are sensitive to IR, and require an IR blocking filter. The Gallium Arsenide Phosphade based photosensor is much less sensitive to IR, was closer to film, like Selenium and CDS sensors.

    If you want deeper IR response, use InGaAs.
     
    Last edited: Dec 3, 2020
  11. a-Se is about 1.99eV or about 623nm. A little high for red, but maybe not so bad.

    I thought I knew in 1979 when I bought my FM that it was silicon, but then recently found
    Nikon literature saying GaAsP.

    Yes GaAsP, with the approrpiate amount of As and P, can set the gap over a wide range,
    from IR (GaAs) up to green (GaP), though the latter is indirect gap. But as far as I know,
    they are noisier than Si, and so not as sensitive at low light levels.

    Otherwise, they would use it for sensors in digital cameras for the same reason.
     
  12. Got a feeling that should be Phosphide.....;)
     
  13. A Nikkormat FT3 is just a camera! A box with room for film inside and mount for a lens.

    The only film Nikon I have left that's fully working, with accurate shutter and needing no repair/adjustment/light-seal replacement is an F801s.

    A quick surf of eBay prices shows me that I could buy an F801s/N8008s for a tiny fraction of what any useable Nikkormat FT3 would cost, and for less than any repair cost to a fully mechanical camera.

    The F801s also has far more consistent and accurate metering than any of its predecessors.

    So why throw good money after bad, and waste time that could be spent taking actual pictures?
    Pictures that nobody will know whether they came from an old relic of a camera, or from something slightly more recent.
     
  14. Because for some, the result is not the 'be-all-and-end-all of photography'.

    YMMV, I know mine does!
     
  15. It is. As Hasselblad 500, Smena 8, ....
    Through my working years, at the start in particularly, I learned to use all sorts of avaliable hand tools to get the desired results, but I also learned, in time, to appreciate the quality of the good tools and what those can do for me.

    I can understand you, but can`t agree with you. I personally enjoy both, using cameras as a photographic tools. And I also enjoy them as a kind of technical legacy, which needs some care and attention from time to time to keep them functional. I simply like to work on them, in the range of my (unfortunately) limited abilities. It is a satisfying hobby. I found time, fixing the camera, to be spend more than well. As well as the (still available) time spent on actual taking pictures, even the ones that will be appreciated just by me. And in the end, my Nikkormat was simply cheap.

    It is just a matter of personal preferences, interests and wishes.
     
  16. Yes- typo on my part.
     
  17. I don't know about the one above, but I got one last year for $44.
    You can decide whether that is too much or not. I think I like the FT3 as it is AI
    and pretty much the immediate predecessor to the FM. Slightly more fun
    than the FTn or FT2. I have enough lenses with the fork on them, but also
    enough without one.

    In addition to the cost, one could ask about the time spent getting one to work.
    Mine works well enough without any work, though.

    On the other hand, I have lately been working on fixing strings of Christmas lights instead
    of throwing them out and buying all new ones. Partly it is the challenge of figuring out why
    they don't work. (I had one with 20 out of 50 bulbs burned out.) And also the feeling of
    having them work again. Why do people do crosswork puzzles or Sudokus?
    Just for the fun of it!

    So, yes, for picture taking ability fixing up an FT3 isn't worth the time spent doing it, but then
    again much of photography probably isn't worth the time we spend on it. That isn't why people
    work on hobbies or puzzles. I presume the FT3 isn't being used for professional work.
     
  18. I realise that.
    I've done my share of repairing cameras, lenses, shutters, flash, etc. Out of necessity, being unable to afford replacement or losing the use of the kit to a repair shop.

    But there comes a point when old gear is falling apart faster than you can keep up with its maintenance, and you just say 'enough is enough!'.

    Then a reliable piece of gear is a complete blessing, worth twenty 'nice' old pieces of 'precision engineering'.
     
    mike_halliwell likes this.
  19. Yes.

    Well, there are some who work on them just for the fun of doing it, which makes as much sense is about any other hobby.

    But if you aren't working on them for fun, it makes sense to compare the cost of fixing to the cost of buying a used one.
    There are a lot of old cameras out there that still work, if one wants to use them. Many not very rare.
     
  20. I just spent about $35 trying to repair my old Gitzo quick release I had for thirty years. I spent two days checking and ordering knobs, bolts, springs, washers, etc. I almost got it to work perfectly. But no cigar. So I finally gave up and ordered a new Kessler quick release. The only variable was I bought an Arca Swiss quick release plate, rather than Kessler's, for my RB67 to operate with the new Kessler. However, the Kessler clamp didn't hold it tight enough. So now I'll have to use the Kessler plate for that camera too. I'm using the Kessler plates for my Chamonix 4x5 and Nikon 35mm.

    Cutting corners and improvising is sometimes a dead end. Often it just pays to pay what you have to and do it right, to begin with.
     

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