Lux?

Discussion in 'Photography' started by angelsbridge, May 28, 2005.

  1. angelsbridge

    angelsbridge Guest

    A camera has a min. ilumination of 3 lux, How dark would that be?? I'm
    looking at cams for home monitoring use. Thank you!

    Yvonne
     
    angelsbridge, May 28, 2005
    #1
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  2. I think Lux is the metric equivalent of "foot candles" which is the amount
    of light falling on an object lit by one candle one foot away so 3 Lux would
    be the amount of light falling on an object illuminated by three candles one
    foot away.

    I say again I think. I may be corrected about this but all the same 3 Lux is
    not very bright

    Perrian
     
    Perrian Robertson, May 29, 2005
    #2
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  3. angelsbridge

    Dave Kearton Guest

    | || A camera has a min. ilumination of 3 lux, How dark would that be??
    || I'm looking at cams for home monitoring use. Thank you!
    |
    | I think Lux is the metric equivalent of "foot candles" which is the
    | amount of light falling on an object lit by one candle one foot away
    | so 3 Lux would be the amount of light falling on an object
    | illuminated by three candles one foot away.
    |
    | I say again I think. I may be corrected about this but all the same 3
    | Lux is not very bright
    |
    | Perrian



    Quoting from one of my CCTV supplier's catalogues .....



    Lux Description

    50,000 Summer sunhine
    5,000 Overcast sky
    500 Well lit office
    300 minumum for easy
    reading
    50 passageway / outside
    wkg area
    15 good
    main-road-lighting
    5 typical side-road
    lighting
    2 minimum security risk
    lighting
    1 Twilight
    ..3 Clear full-moon
    ..1 typical
    moonlight/cloudy sky
    ..001 typical starlight
    ..0001 poor starlight






    Bearing in mind that the minimum illumination figure can also be massaged as
    well for marketing reasons, it's not a really good way to plan a
    surveillance system. In surveillance-speak, 'minimum
    illumination' is the lowest amount of light that an object of X%
    reflectivity can be identified through the camera. Obviously, a
    black or dark green object will be harder to spot in poor light than a white
    one. For the 'min illum' figure to make sense, the reflectivity of
    the test object should be listed as well, however most camera manufacturers
    won't.


    It sounds like you may be looking at one of the simpler colour dome cameras
    that retail for AUD$1-200 in the surveillance stores. Can I
    presume that for home use, you want to check the outside perimeter of the
    house or the identity of the person at the front door, before you get up
    to answer the doorbell ?


    Depending on the size of your house and your budget, you may want to look
    into B&W cameras - only cheapies and Infra Red spotlights. Allow
    for an effective range of 3-5m per camera and about 5-10m per IR spotlight.
    The resultant picture is clear as a bell B&W video, while to the prowler
    outside, it's still as dark as the inside of a brown dog.





    --

    Cheers


    Dave Kearton
     
    Dave Kearton, May 29, 2005
    #3
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