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Thread: Large Format Focal Plane Meter - New Product

  1. #31
    Moderator
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    6,653

    Re: Large Format Focal Plane Meter - New Product

    Quote Originally Posted by Dave Gooding View Post
    Thanks. what sort of range can a film sensibly cover? I did run a series of 20 or 30 test exposures on Ilford HP5 as part of a calibration exercise (to calibrate a sensor against which each unit is checked and adjusted). I measured the negative intensity and plotted it against exposure. It follows an S-curve with a roughly linear region of +/- 4-ish steps in the middle but there are measurable intensity differences between consecutive exposures even at 10 stops away from the nominal, although to the eye these extreme ones have no discernible difference. Would you really operate the film at these extremes?
    If you used a single development time for your negatives, you haven't yet actually tested how long a subject brightness range (SBR) the film can usefully record. There's a whole body of technique around how to manipulate exposure and development, in light of a given film's sensitometric properties, to optimally capture any given SBR.

    There are special film/developer combinations, such as T-Max 100/DI-13, and techniques, such as David Kachel's SLIMTs, that are designed to tame SBRs well beyond 10 stops to make them printable on enlarging paper. If you're going to scan rather than print directly to silver, high-DMax/long-straight-line films like T-Max 400 can capture ridiculous SBRs that, with considerable effort in digital manipulation, can be reduced to something that can go on paper.

    No need to dive into the details of all that if it's not your primary interest. The take-home remains that yes, as a photographer I can use as long a brightness measurement range as you can give me.

  2. #32
    3D-Stereo-Aeropanoramas
    Join Date
    May 2004
    Posts
    126

    Re: Large Format Focal Plane Meter - New Product

    If you remember vivitar 130/LX130 160/LX160 exposure-meter in the 80ties(obsolete since bad electronics used): they offered a spot(aufsatz) dont know english term. with normal dome and flat calotte for GG-metering which i never used. but i still have it. maybe i should try with gossen variosix. maybe not working. production was stopped due to the mentioned problem. LX had motorized wheel.
    www.stereopan.tk
    3DStereo-Aeropanorama-Jungfraujoch

  3. #33

    Re: Large Format Focal Plane Meter - New Product

    Sinar Booster-1 and Probe FCM with Sinar metering back.
    http://www.galerie-photo.com/manuels...ter-system.pdf

    What does this film plane metering system offer that is different?

    Film plane metering can work in a studio setting OK, out doors these systems can bring on a host of difficulties due to light leakage to the metering probe and portability of the system, dust, dirt and more can easily cause problems.

    As for microscope image capture, majority of that need today is done using a digital camera or digital video system that light meters and compensates as needed.
    There was a time when film based microscope photographic systems were a significant item.

    Early example like the Zeiss Photomicroscope & Ultraphot system, Wild Heerbrugg/Leica-Leitz MPS-11 system, Wild Heerbrugg M400 and others. These film photographic systems all had some sort of film plane metering system and uber low vibration shutter systems.


    Bernice

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