Real filters vs. computers for B&W photos

Discussion in 'Digital Photography' started by Al Treacher, Jul 18, 2003.

  1. Al Treacher

    Al Treacher Guest

    I've used "real" filters in the past for taking photos (landscapes
    mainly) on B&W film. My film cameras are now things of the past and I
    shoot entirely digitally. I still intend to take B&W landscapes, and
    would like to get peoples opinions about the relative merits of using
    "real" filters on the front of the lens as opposed to converting the
    digital image to a monochrome and applying computerised colour
    filters.

    Since my main camera (a Canon 10D) does not have the facility to
    capture images as monochrome, I will be still be taking the original
    as a colour photo. (Besides, my understanding is that the mono mode
    that some digital cameras have is relatively poor since it doesn't use
    every pixel on the CCD or CMOS.)

    So... From people's experience, which works better (a subjective
    interpretation, I know!) taking the colour photo with a red or orange
    filter in front of the lens, then converting the photo to a
    monochrome/duotone, or taking a non-filtered colour photo and then
    adjusting the photo in Photoshop? (If the latter, I'd adjust the RGB
    channels - is there a better way?)

    Cheers,
    Al
    Al Treacher, Jul 18, 2003
    #1
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  2. Al Treacher <> wrote in
    news::

    > So... From people's experience, which works better (a subjective
    > interpretation, I know!) taking the colour photo with a red or orange
    > filter in front of the lens, then converting the photo to a
    > monochrome/duotone, or taking a non-filtered colour photo and then
    > adjusting the photo in Photoshop? (If the latter, I'd adjust the RGB
    > channels - is there a better way?)
    >


    I do not use real filters (except for IR-filters). I think
    it works very well to simulate real filters, i.e. yellow
    or green filters in software. But I don't think that you
    can simulate a deep red or blue filter. To get very dark
    skies you shall use a deep red filter (or IR-filter).
    I have not tested to use red filters with my Canon G2,
    but with my previous camera (Sony S70) it did not work
    at all. The automatic exposure went just out the window
    and overexposed the red, correctly exposed the green and
    underexposed the blue. So ... that was useless.


    Roland
    Roland Karlsson, Jul 18, 2003
    #2
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  3. Other than polarizing filters, you can reproduce most other filters in
    software. How well depends on the software and your skill with it.

    There are some exceptions, but in general it works well.

    --
    Joseph E. Meehan

    26 + 6 = 1 It's Irish Math


    "Al Treacher" <> wrote in message
    news:...
    > I've used "real" filters in the past for taking photos (landscapes
    > mainly) on B&W film. My film cameras are now things of the past and I
    > shoot entirely digitally. I still intend to take B&W landscapes, and
    > would like to get peoples opinions about the relative merits of using
    > "real" filters on the front of the lens as opposed to converting the
    > digital image to a monochrome and applying computerised colour
    > filters.
    >
    > Since my main camera (a Canon 10D) does not have the facility to
    > capture images as monochrome, I will be still be taking the original
    > as a colour photo. (Besides, my understanding is that the mono mode
    > that some digital cameras have is relatively poor since it doesn't use
    > every pixel on the CCD or CMOS.)
    >
    > So... From people's experience, which works better (a subjective
    > interpretation, I know!) taking the colour photo with a red or orange
    > filter in front of the lens, then converting the photo to a
    > monochrome/duotone, or taking a non-filtered colour photo and then
    > adjusting the photo in Photoshop? (If the latter, I'd adjust the RGB
    > channels - is there a better way?)
    >
    > Cheers,
    > Al
    >
    Joseph Meehan, Jul 18, 2003
    #3
  4. Speaking of a library of filters, I am currently evaluating a software
    package called "Picture Window Pro," which has just that -- a library
    of filters! I'm still evaluating how to actually use them, but they
    are there! I shot 100% b&w for many years before moving to digital,
    and I think you should be able to emulate almost any effect (IR
    excluded) with digital & RBG channel manip. that you can do with b&w.
    After all, color film is panchromatic, and each one has a
    sensitivity/response to different wavelengths. Adjust the RBG curves
    in you favorite image software, and you should be able to get where
    you want to be.

    That's theory on my part, tho. I just got my digital camera a few
    weeks ago, and I'm still learning a bit. Esp. on the desktop
    software.

    Picture Window Pro allows 16 bit/ch manipulation for all of it's
    functions, and it runs remarkably fast. Available at
    http://www.dl-c.com for .LT. $100. I don't work for them, I'm just
    impressed with my trial copy, so I thought I'd pass it along.

    James Carpenter
    Just west of Guthrie, KY.
    James Carpenter, Jul 19, 2003
    #4
  5. "Joseph Meehan" <> writes:

    > Other than polarizing filters, you can reproduce most other filters
    > in software. How well depends on the software and your skill with
    > it.


    > There are some exceptions, but in general it works well.


    You can only *aproximate* the effects of on camera filters, and in
    many cases, you can't even do that. No way `hosay... And this is
    not including effects like having your blue channel way down in the
    noise if you shoot under dimmed tungsten.

    Once the light hits the CCD, you have 3 numbers that replace an
    infinite number of values. Your software has NOTHING to distinguish
    the hues of the 3 primaries. You can only vary the magnitude, you can
    do nothing about the cut-off wavelength. That is fixed by the filters
    on your CCD.

    If you insist in believing that any software can replace filters, then
    explain why they spend a huge sum of $$ putting the RGB arrays on the
    CCD and don't just `do it in software'!

    --
    Paul Repacholi 1 Crescent Rd.,
    +61 (08) 9257-1001 Kalamunda.
    West Australia 6076
    comp.os.vms,- The Older, Grumpier Slashdot
    Raw, Cooked or Well-done, it's all half baked.
    EPIC, The Architecture of the future, always has been, always will be.
    Paul Repacholi, Jul 19, 2003
    #5
  6. "Joseph Meehan" <> wrote in message
    news:UoYRa.1064$...
    > Other than polarizing filters, you can reproduce most other filters in
    > software. How well depends on the software and your skill with it.
    >
    > There are some exceptions, but in general it works well.
    >
    > --
    > Joseph E. Meehan


    Does that include a haze (UV) filter?

    >
    > 26 + 6 = 1 It's Irish Math
    >
    >
    > "Al Treacher" <> wrote in message
    > news:...
    > > I've used "real" filters in the past for taking photos (landscapes
    > > mainly) on B&W film. My film cameras are now things of the past and I
    > > shoot entirely digitally. I still intend to take B&W landscapes, and
    > > would like to get peoples opinions about the relative merits of using
    > > "real" filters on the front of the lens as opposed to converting the
    > > digital image to a monochrome and applying computerised colour
    > > filters.
    > >
    > > Since my main camera (a Canon 10D) does not have the facility to
    > > capture images as monochrome, I will be still be taking the original
    > > as a colour photo. (Besides, my understanding is that the mono mode
    > > that some digital cameras have is relatively poor since it doesn't use
    > > every pixel on the CCD or CMOS.)
    > >
    > > So... From people's experience, which works better (a subjective
    > > interpretation, I know!) taking the colour photo with a red or orange
    > > filter in front of the lens, then converting the photo to a
    > > monochrome/duotone, or taking a non-filtered colour photo and then
    > > adjusting the photo in Photoshop? (If the latter, I'd adjust the RGB
    > > channels - is there a better way?)
    > >
    > > Cheers,
    > > Al
    > >

    >
    >
    Marvin Margoshes, Jul 19, 2003
    #6
  7. --
    Joseph E. Meehan

    26 + 6 = 1 It's Irish Math


    "Marvin Margoshes" <> wrote in message
    news:...
    >
    > "Joseph Meehan" <> wrote in message
    > news:UoYRa.1064$...
    > > Other than polarizing filters, you can reproduce most other filters

    in
    > > software. How well depends on the software and your skill with it.
    > >
    > > There are some exceptions, but in general it works well.
    > >
    > > --
    > > Joseph E. Meehan

    >
    > Does that include a haze (UV) filter?


    Yes.
    ..
    ..
    ..
    ..
    ..
    ..
    ..
    ..
    ..
    ..
    ..

    The word "exception" includes it. (;-)

    >
    > >
    > > 26 + 6 = 1 It's Irish Math
    > >
    > >
    > > "Al Treacher" <> wrote in message
    > > news:...
    > > > I've used "real" filters in the past for taking photos (landscapes
    > > > mainly) on B&W film. My film cameras are now things of the past and I
    > > > shoot entirely digitally. I still intend to take B&W landscapes, and
    > > > would like to get peoples opinions about the relative merits of using
    > > > "real" filters on the front of the lens as opposed to converting the
    > > > digital image to a monochrome and applying computerised colour
    > > > filters.
    > > >
    > > > Since my main camera (a Canon 10D) does not have the facility to
    > > > capture images as monochrome, I will be still be taking the original
    > > > as a colour photo. (Besides, my understanding is that the mono mode
    > > > that some digital cameras have is relatively poor since it doesn't use
    > > > every pixel on the CCD or CMOS.)
    > > >
    > > > So... From people's experience, which works better (a subjective
    > > > interpretation, I know!) taking the colour photo with a red or orange
    > > > filter in front of the lens, then converting the photo to a
    > > > monochrome/duotone, or taking a non-filtered colour photo and then
    > > > adjusting the photo in Photoshop? (If the latter, I'd adjust the RGB
    > > > channels - is there a better way?)
    > > >
    > > > Cheers,
    > > > Al
    > > >

    > >
    > >

    >
    >
    Joseph Meehan, Jul 19, 2003
    #7
  8. Al Treacher

    ralford Guest


    >
    > If you insist in believing that any software can replace filters, then
    > explain why they spend a huge sum of $$ putting the RGB arrays on the
    > CCD and don't just `do it in software'!
    >


    wow - talk about a logical leap off a cliff! The reason for there analog
    ccd values is trivial (to most) - one needs 3 independent observations to
    provide a basis set to expand the color space. well, technically they don't
    need to be independent, only non collinear - but that's another story.

    rma
    ralford, Jul 20, 2003
    #8
  9. Al Treacher

    Guest

    In message <>,
    Paul Repacholi <> wrote:

    >And this is
    >not including effects like having your blue channel way down in the
    >noise if you shoot under dimmed tungsten.


    The Metropolitan Museum of Art in NYC seems to run their incandescent
    lights either on some dimmer, or at a reduced voltage. There is almost
    no blue at all. There really isn't enough light to be using filters,
    either, without a tripod.
    --

    <>>< ><<> ><<> <>>< ><<> <>>< <>>< ><<>
    John P Sheehy <>
    ><<> <>>< <>>< ><<> <>>< ><<> ><<> <>><
    , Jul 20, 2003
    #9
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