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. OP
    OP
    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 Member

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

    Photo-gear Member

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    My mistake: of course, I used 9 volts.
     
  11. OP
    OP
    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.
     
  13. Ryank

    Ryank Member

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    Is it worth it to buy a Gossen Lunasix 2 (or any vintage light meter for that matter) now for relatively cheap (500 South African rands)? I'm on a budget but I just bought a Mamiya RB67 and want to make the best use of it as I can so I'm worried buying a cheaper older light meter will bite me in the ass later.
     
  14. AgX

    AgX Member

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    Such screw, as with most professional analog meters for whatever use, is only to re-adjust the zero-position:
    turn the screw until the needle is at the zero position with the meter switched off and in your common metering position.

    However, a lightmeter will not be off 2 stops from zero position, and you would have recognized such anyway.
    Any other re-calibration needs dissambly of that meter and working on the rheostats.
     
  15. M Carter

    M Carter Member

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    Ehh. Get a new or new-ish meter, not an antique. I imagine gear is harder to find in south africa, but my Sekonic 308 has lasted me 2 decades and is still made today. I've gone through a good dozen-plus camera bodies and I still use it, whether with my RB out in the desert, shooting film with old Nikons or Hawkeyes or isolettes or pinholes, shooting digital stills for clients, or doing music videos. A good meter will outlast a lot of other gear.
     
  16. Helios 1984

    Helios 1984 Member

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    Have you reset the exposure compensation? The white marker should line up with the 0
    [​IMG]
     
  17. AgX

    AgX Member

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    Respectively the trapezoid notch at the dial with the corresponding mark at the compensation scale.
     
  18. mgb74

    mgb74 Subscriber

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    Start with your reference point: your known reliable F80. I assume you know it's reliable because it delivers good results. But good results with b/w film, color negative, color slides? If with negative film (b/w or color), you could be a stop off and still think you're getting proper exposure (unless your "reading" the negative and are experienced - which you may be). Or, for example, your camera could be 1/2 stop off in one direction and the meter 1/2 stop off in the other direction.

    Then, what lens are you using and does it's field of view match the angle of acceptance of the meter? If not, then you are measuring 2 different scenes. Unless you're measuring something like a wall that fills the entire field of view. When you're using a handheld reflective meter outside, it's pretty easy to tip it so you're getting a bit more or a bit less sky than your lens is taking in. So I would test on both an interior and exterior wall and see what you get. Make sure shifting clouds don't affect your test readings.

    Sunny 16 is like a hand grenade - close is good enough. There are just so many variations, such as the angle of the sun, that a 1 stop variation is quite common.
     
    Last edited: Jun 24, 2017
  19. Ryank

    Ryank Member

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    Thanks for the feedback. It sometimes can be hard to find but more often than not you'll find what you're looking for. I think I'll save up for one of those 308s.