Gossen Luna Pro F battery test

Discussion in 'Lighting' started by alanrockwood, Jan 25, 2009.

  1. alanrockwood

    alanrockwood Member

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    I have two Luna Pro F light meters. Both fail the battery test when a fresh 9V battery is installed. The needle goes off-scale to the right of the green "BATT" box on the dial. I understand that some other people see the same thing. How common is this problem, and does this problem affect the meter calibration?

    Interestingly, if I use a battery voltage of ~7.6 volts the meter passes the battery test, barely, though it is still on the high side of the "BATT" box. I did this diagnosis by temporarily putting two silicon diodes in series with the battery to get ~7.6 volts.

    Alan
     
  2. Fred Aspen

    Fred Aspen Member

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    I don't have a manual in front of me but I think early models read in the 'zone' but later meters, probably to save costs, simply stated in the manuals that a good battery reads 'to the right' of the battery indication zone. My 'F' read to the right and I have had SBCs that did both.

    -Fred
     
  3. alanrockwood

    alanrockwood Member

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    I just did a comparison test... my two Luna Pro F meters against the TTL meter of my canon T2. The indicated exposures agreed very well between the three. It seem unlikely that all three would be wrong, and especially that they would all agree on the wrong exposure value. Therefore, I think the meter is reading correctly

    The manual I have says that the needle should be well within in the "BATT" zone, and it has a photo in the manual showing it. I wonder if the manual contains an error in its description of the battery test.
     
  4. Q.G.

    Q.G. Inactive

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    As long as the needle is not to the left of the battery test zone, it's fine. No worries.
     
  5. Lee L

    Lee L Member

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    More likely it contains a poor, or slightly inaccurate translation from the original German instructions to English.

    Just checked it. The original German instructions include the phrase "oder rechts davon steht", with reference to the green BATT. box, which basically means "or stays to the right of" the green BATT. box.

    Now if I could only read Japanese I could figure out how to use a Nikon. :smile:

    Lee
     
  6. R/D

    R/D Member

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    Ok I have a question. I just received a Luna Pro SBC and the battery meter immediately goes to the left when I push the test button. A fresh 9V was installed. Does anyone think this will be a problem ?
     
    Last edited by a moderator: Feb 2, 2009
  7. MattKing

    MattKing Subscriber

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    To the left of where? If it is to the left of the display itself, it sounds like a problem.

    Matt
     
  8. R/D

    R/D Member

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    Thanks Matt,

    When I turn the meter on it jumps up to the reading its set at but when the battery test button is depressed it dives all the way down to the left. No worries though, I bought it from Ebay along with a spot attachment hoping there wasn't a problem. I contacted the seller and he was very cool about it saying I could return it and get a refund. I suppose that's what I get for trying to save a few bucks when I should have just went to KEH.