Shepherd FM990 Flash/Ambient Meter

Discussion in 'Lighting Equipment' started by BeBu Lamar, Sep 11, 2018.

  1. Does anyone have the instruction for this? I found the one for the FM900 but it's quite different.
     
  2. Not much to tell about it. You fit the flash synch cable to the P-C socket and press the button!

    I have the FM-1000, which has a 7 segment readout instead of the row of LEDs.

    You set the shutter speed on the little thumbwheel, take a reading, transfer the indicated number to the calculator dial and read off the aperture. That's about it.

    IIRC, the shutter speed selection only runs from 1/60th to 1/500th. So it's only moderately useful as an ambient meter in quite bright light. However, you can press the button multiple times to get corresponding 2x, 3x, 4x etc. readings.

    Oh, yes. Nearly forgot. You need to press the reset button before taking a reading. The FM-1000 also has a recall button for the last reading, but I don't think the 990 has that feature.

    You can also use open flash I believe, and the meter will respond to an un-synchronised flash within a few seconds of pressing the reset button.
     
    Last edited: Sep 12, 2018
  3. I think I figure it out now. There is a reset/on button on top. The flash button at the bottom. The shutter speed setting. The dome in and out for incident and reflective. Push the reset/on button the meter turn on and turn itself off after sometime. I didn't know this and didn't know how to turn it off. Push the Flash button to make either ambient or flash measurement. The led would light up until the reset/on button is pressed.
    The calculator dial doesn't do anything so I simply do it in my head.
     
  4. The calculator dial translates the arbitrary number indicated by the LED bars into a real aperture number, dependant on the ISO setting. There's no simple formula you can apply to get from the LED bars to an aperture number.

    There's also an extra LED that indicates a half stop more exposure than the illuminated bar. It doubles as a 'low battery' indicator, IIRC.

    I believe the operation of the FM-990 is identical to that of the FM-900, apart from the added ability to set a shutter speed. Therefore you can follow the FM-900 instruction manual from Mike Butkus's site.

    Incidentally, I've checked my FM-1000 against a Minolta Autometer IVF, and a Quantum Calcu-light flashmeter. They all agree within a small fraction of a stop when used in incident mode.

    One slight issue I had was with the trigger circuit. It was obviously designed before low-voltage digital-compatible flashes became common, and sometimes fails to fire a flash with a 'safe' 5v trigger. I modified mine to make it more reliable, by replacing a small coupling capacitor inside. I don't recommend that unless you know your way around a circuit board.
     
    Last edited: Sep 12, 2018
  5. P.S.
    There's an FM-990 being advertised on eBay at the moment, complete with instruction manual, apparently.

    Maybe if you contact the seller he'll send you a picture of the relevant pages of the manual. It's doubtless multi-lingual, with only a small section in anyone's native language.
     
  6. Well the scale is 1 value lower than I normally associate my number to the aperture. I use 0 for f/1.0 and the meter 0 is for f/2.
    So the procedure is take the reading. Add to the reading the number of stop from ISO 100. If you use ISO 100 then use the number as is. For ISO 400 add 2. Then with f/1.4 as 0 then for example 5 would be f/8.0.
     
  7. But why not just read the calculator scale?

    That's what it's there for.
     

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