Through the lens metering

Discussion in 'Talk About Large Format Gear' started by John Barford, Jun 30, 2017.

  1. John Barford

    John Barford New Member

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    I have recently made a 4x5 camera and found myself confused with bellows extension, effects of filters, and testing homemade lenses. I decided a through the lens meter would help me resolve these issues. After much trial and even more error I managed to construct two working prototypes. The principles are as follows if you wish to give it a go.
    Two basic parts are required.
    PROTOTYPE 1
    1) An old 4x5 plastic cut film holder.
    2) A lux meter one with the sensor on the end of a curly wire (cheap as possible) plenty of these on ebay.
    From the Lux Meter remove the photodiode and its attached curly wire from the sensor. It looks like a tiny glass square. Mount this photodiode centrally in the cut film holder. Put film holder in camera Swirch on lux meter. Calibrate with light meter. Draw table of results.
    PROTOTYPE 2 (MY PREFERRED OPTION)
    Replace photodiode with solar cell. I found one on ebay which was almost exactly 4x5. This amazingly gave me exact Lux readings.
     
  2. mpirie

    mpirie New Member

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    I seem to remember that Sinar made a similar device (though no doubt way more expensive).

    My Gossen Profisix has connectors on the top allowing the attachment of external devices such as spot and microscope attachments.
     
  3. Stephen Batey

    Stephen Batey Well-Known Member

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    And my Lunasix3 takes a ground glass probe attachment (which I have...)
     
  4. David M

    David M Member

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    The solar panel idea is brilliant. Well done. Will there be a commercial version?
     

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