Gossen Lunasix F

Discussion in 'Lighting' started by Photo-gear, Apr 8, 2012.

  1. Photo-gear

    Photo-gear Member

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    I just acquired a lightmeter Gossen Lunasix F.

    After learning how to use it, I realized there might be a calibrating problem. As a matter of fact, it looks like the measuring is one stop away (even 2) from the reading of another lightmeter camera (Nikon F80). Even the f16 rule doesn't seem to give equivalent results with the Lunasix.

    I don't have shoot accordingly to the Lunasix F yet, so I unfortunately could not give shot samples.

    Someone knows whether I could calibrate the Lunasix with the screw on the back. If so, how do I do it?

    Yours,
    :munch:
     
  2. CGW

    CGW Member

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    If you're using it in incident mode, keep in mind that your F80 reads reflected light, right?

    To calibrate it, use a known-accurate meter. This is the sort of problem that's always stopped me from buying old meters.
     
  3. Photo-gear

    Photo-gear Member

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    I used reflective mode.

    But, yeah, not too many gears get old easy, except some lenses...

     
  4. vedmak

    vedmak Subscriber

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    what did you test it on? a gray card?
     
  5. Photo-gear

    Photo-gear Member

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    Unfortunately not.
    As I said I compared the measuring by both the reliable camera (Nikon F80) and the Lunasix F. Not only on one scene but on several. Always with the same difference by one or two stops.
     
  6. Wade D

    Wade D Member

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    It might need a battery with proper voltage. Most of the older meters used a 625 mercury battery rated at 1.35v which is no longer available. The newer batteries which fit are rated at 1.55v so the error might be 1 or 2 stops in the reading. Adapters are made to reduce the voltage and give a true reading. The zero adjust screw won't compensate for the error.
     
  7. Photo-gear

    Photo-gear Member

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    this one takes 6v and there is a fresh one in the compartment.
     
  8. MattKing

    MattKing Subscriber

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    A Lunasix F should take a 9 volt battery.

    Any chance that there is an exposure modification dialed in on the ring that is there for that purpose?
     
  9. Karel Van den Fontey

    Karel Van den Fontey Member

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    I usually start with a battery check and zero adjustment on the meter (usually a small scew marked as such on the back of the instrument). Then a test on a landscape with normal ligt (a cloudy day is even better) and a check with a camera with a normal lens (50 mm on a film camera) will do the job. Try to point away from the sun, a big grey surface is perfect. Hold meter and camera in the same direction. Std meter function on lightmeter, no bulb on the cell. Std meter function on camera, no spot metering.
    In such a test, a meter on a camera or a lightmeter can differ 1 stop, no 2 stops.
    FYI, You can always download the instruction book for your meter from the Gossen site (Germany). The also keep the instruction books for old meters availiable. Nice site.
     
  10. Photo-gear

    Photo-gear Member

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    My mistake: of course, I used 9 volts.
     
  11. Photo-gear

    Photo-gear Member

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    You kind of summarize how I compare both, the camera lightmeter and the Lunasix F.
    I also did find the Gossen manual.
     
  12. E. von Hoegh

    E. von Hoegh Member

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    Do the zero adjustment first, preferably with the battery removed from the meter and the meter held so the needle is horizontal. The instruction manual will explain.