ND or Circular polarizing filter??

Discussion in '35mm Cameras' started by bloke, May 12, 2004.

  1. bloke

    bloke Guest

    Hi,

    I´m about to get an ND8 filter to get longer expsure time in light
    environments and with use with hoya r72 ir filter.I use a sony-v1 for
    this.

    my question is could I get an Circular polarizing filter instead. with
    this I could adjust the amout of ligt it will let trough right? would
    this be a better solution for me or does these two filter work very
    differently?

    cheers
     
    bloke, May 12, 2004
    #1
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  2. bloke

    Peter Chant Guest

    I think you can or could get variable ND filters made from two rotating
    polarised elements. I suppose two stacked linear polarisers would work
    that way but I assume that a circular polariser on the front would not
    work.

    I would imagine that an ND8 would be a much cheaper option.
     
    Peter Chant, May 12, 2004
    #2
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  3. bloke

    Slingblade Guest

    they work very differently, and the ND8 would have a higher filter
    factor than a Cir Pol. Why not get both though. Polarizers are
    probably the single most useful filter there is...but a good ND filter
    is also very desirable.
     
    Slingblade, May 13, 2004
    #3
  4. bloke

    Tony Spadaro Guest

    ND filters are completely consistant and do not affect skies. Unless you are
    desperate use an ND for longer exposures and save the pol for when you want
    the effect.
     
    Tony Spadaro, May 13, 2004
    #4
  5. They are not the same thing, but a polarizing filter will cut the total
    amount of light just like a ND filter.

    With two polarizing filters you can adjust the amount of reduction from
    the combined total to 100% (you are right Peter)

    I would suggest getting one polarizing filter to start. See if that
    does it for you. Keep in mind that when you use it to reduce the light, you
    may also be causing some other changes. Watch out for them. Most of the
    time you can adjust them out by rotation the polarizing filter.
     
    Joseph Meehan, May 13, 2004
    #5
  6. bloke

    bloke Guest

    thanks for you helpful answers!!
     
    bloke, May 13, 2004
    #6
  7. bloke

    croweflight Guest

    Are ND filters transparent to IR? When I am using my Hoya 72 I can
    "see" right though sun glasses. I use a Olympus 2020 for my digital IR
    stuff. And film. Have not tryed ND filters as the sensitivity is low
    for IR anyway.
     
    croweflight, May 13, 2004
    #7
  8. I have not seen any published facts, but I would have to guess that they
    are as transparent to IR as they are to visible light. I believe IR has the
    same potential for polarization as visible light as well.
     
    Joseph Meehan, May 14, 2004
    #8
  9. bloke

    Peter Irwin Guest

    It can depend on the technology used to make the filters.
    The traditional photographic ND filters exemplified by the
    Kodak Wratten 96 gels, have only half the density at 1000
    nanometres as they do in the visible spectrum. Other filters
    such as the nickel alloy on glass types used for scientific
    purposes hold up very well at infrared wavelengths.

    ND filters made from exposed and developed black and white film
    block infrared light more than they block visible light.

    see: <http://www.drdale.com/eclipses/filters.htm> for graphs.

    Peter.
     
    Peter Irwin, May 14, 2004
    #9
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