do i need rotating polarizers on my lamps????

Discussion in 'Digital Photography' started by bruin70@mail.com, May 3, 2006.

  1. Guest

    i shoot my artwork. they are oils and there are lots of reflections.

    a pro finally showed me how to shoot artwork. he had polarizer filters
    on both his lamps and his camera....he rotated his lamp filters until
    he got as much glare/reflection out as possible, and then when he
    fiddled with his camera polarizer, he eliminated all the glare. so now
    i know what to do and what to get.

    i went to adorama here in nyc and asked to see their light filters. the
    lamp polarizers were stationary, ie,,,they could not rotate. he said he
    didn't have lamp polarizers on a rotating frame.

    my question is,,,,is this right. should they be able to rotate???,,, or
    does it matter if i can rotate the lamp filters or not? IT CERTAINLY
    MADE A DIFFERENCE when i watched the photographer. is it necessary to
    rotate the lamp filters to get all the glare out?

    thanks
     
    , May 3, 2006
    #1
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  2. Rutger Guest

    <> schreef in bericht
    news:...
    >i shoot my artwork. they are oils and there are lots of reflections.
    >
    > a pro finally showed me how to shoot artwork. he had polarizer filters
    > on both his lamps and his camera....he rotated his lamp filters until
    > he got as much glare/reflection out as possible, and then when he
    > fiddled with his camera polarizer, he eliminated all the glare. so now
    > i know what to do and what to get.
    >
    > i went to adorama here in nyc and asked to see their light filters. the
    > lamp polarizers were stationary, ie,,,they could not rotate. he said he
    > didn't have lamp polarizers on a rotating frame.
    >
    > my question is,,,,is this right. should they be able to rotate???,,, or
    > does it matter if i can rotate the lamp filters or not? IT CERTAINLY
    > MADE A DIFFERENCE when i watched the photographer. is it necessary to
    > rotate the lamp filters to get all the glare out?
    >
    > thanks


    Please do not multipost. Answer is already in other group.

    Rutger


    --
    http://www.flickr.com/photos/zwaarddrager/
     
    Rutger, May 3, 2006
    #2
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  3. In article <>,
    writes
    >i shoot my artwork. they are oils and there are lots of reflections.
    >
    >a pro finally showed me how to shoot artwork. he had polarizer filters
    >on both his lamps and his camera....he rotated his lamp filters until
    >he got as much glare/reflection out as possible, and then when he
    >fiddled with his camera polarizer, he eliminated all the glare. so now
    >i know what to do and what to get.
    >
    >i went to adorama here in nyc and asked to see their light filters. the
    >lamp polarizers were stationary, ie,,,they could not rotate. he said he
    >didn't have lamp polarizers on a rotating frame.
    >
    >my question is,,,,is this right. should they be able to rotate???,,, or
    >does it matter if i can rotate the lamp filters or not? IT CERTAINLY
    >MADE A DIFFERENCE when i watched the photographer. is it necessary to
    >rotate the lamp filters to get all the glare out?
    >
    >thanks
    >

    When using polarised lighting with several lamps, the important thing is
    to get the light from the lamps polarised in the same plane. Otherwise,
    no position of the camera polariser will be "right". Ideally, to do
    this, the filters on the lamps should be capable of rotation to align
    them. If they are screw-in filters, then it may be possible to align
    them by simply not screwing them all the way home. If not, can you
    rotate the whole lamp? Do you need to use more than one lamp? If you can
    manage with one lamp and a reflector, you may find that a rotating
    camera polariser will achieve the desired result.

    However, as a first question, do you really need to polarise the light
    sources? For a simple flat piece of artwork such as a painting, you may
    find that just a polariser on the camera will eliminate most reflections
    if rotated to the optimum position.

    You may find this book helpful: "How to Photograph Works of Art", by
    Sheldan Collins, Amphoto 1992, ISBN 0-8174-4019-4 (there may be a later
    edition). The procedure for aligning polarised light sources is
    described on page 65, along with some drawbacks of the techniques
    (mainly difficulty in avoiding colour imbalances).

    David
    --
    David Littlewood
     
    David Littlewood, May 3, 2006
    #3
  4. george Guest

    "David Littlewood" <> wrote in message
    news:...
    > In article <>,
    > writes
    >>i shoot my artwork. they are oils and there are lots of reflections.
    >>
    >>a pro finally showed me how to shoot artwork. he had polarizer filters
    >>on both his lamps and his camera....he rotated his lamp filters until
    >>he got as much glare/reflection out as possible, and then when he
    >>fiddled with his camera polarizer, he eliminated all the glare. so now
    >>i know what to do and what to get.
    >>
    >>i went to adorama here in nyc and asked to see their light filters. the
    >>lamp polarizers were stationary, ie,,,they could not rotate. he said he
    >>didn't have lamp polarizers on a rotating frame.
    >>
    >>my question is,,,,is this right. should they be able to rotate???,,, or
    >>does it matter if i can rotate the lamp filters or not? IT CERTAINLY
    >>MADE A DIFFERENCE when i watched the photographer. is it necessary to
    >>rotate the lamp filters to get all the glare out?
    >>
    >>thanks
    >>

    > When using polarised lighting with several lamps, the important thing is
    > to get the light from the lamps polarised in the same plane. Otherwise, no
    > position of the camera polariser will be "right". Ideally, to do this, the
    > filters on the lamps should be capable of rotation to align them. If they
    > are screw-in filters, then it may be possible to align them by simply not
    > screwing them all the way home. If not, can you rotate the whole lamp? Do
    > you need to use more than one lamp? If you can manage with one lamp and a
    > reflector, you may find that a rotating camera polariser will achieve the
    > desired result.
    >

    Does this also mean that the lights have to be at the same power setting?
    The thinking here is that all the lights I've ever measured the color temp
    on change (slightly) at different power settings so that would mean that
    you're getting different wavelengths of light.

    > However, as a first question, do you really need to polarise the light
    > sources? For a simple flat piece of artwork such as a painting, you may
    > find that just a polariser on the camera will eliminate most reflections
    > if rotated to the optimum position.
    >
    > You may find this book helpful: "How to Photograph Works of Art", by
    > Sheldan Collins, Amphoto 1992, ISBN 0-8174-4019-4 (there may be a later
    > edition). The procedure for aligning polarised light sources is described
    > on page 65, along with some drawbacks of the techniques (mainly difficulty
    > in avoiding colour imbalances).
    >
    > David
    > --
    > David Littlewood
     
    george, May 3, 2006
    #4
  5. Guest

    thanks. since this is not my profession, i am trying to get away with
    as little as possible. my studio doesn't allow for the space.

    the pro told me his set-up was $xxxx.

    i need two lamps to get an even distribution of light. there is a lot
    of glare on an oil painting. i guess "reflection" was the wrong word
    since the paintings don't actually reflect anything. but the surfaces
    are shiny enough to produce glare that "milks out" the color.

    i tried using only the polarizer on my camera, and it was virtually
    useless in eliminating glare. it only eliminated glare from by placing
    the camera at an angle, but i have to shoot my artwork straight on.
     
    , May 3, 2006
    #5
  6. Guest

    sorry.....i didn't know one post gets read everywhere. :):)
     
    , May 3, 2006
    #6
  7. wrote:
    >i shoot my artwork. they are oils and there are lots of reflections.
    >
    > a pro finally showed me how to shoot artwork. he had polarizer filters
    > on both his lamps and his camera....he rotated his lamp filters until
    > he got as much glare/reflection out as possible, and then when he
    > fiddled with his camera polarizer, he eliminated all the glare. so now
    > i know what to do and what to get.
    >
    > i went to adorama here in nyc and asked to see their light filters.
    > the lamp polarizers were stationary, ie,,,they could not rotate. he
    > said he didn't have lamp polarizers on a rotating frame.
    >
    > my question is,,,,is this right. should they be able to rotate???,,,
    > or does it matter if i can rotate the lamp filters or not? IT
    > CERTAINLY MADE A DIFFERENCE when i watched the photographer. is it
    > necessary to rotate the lamp filters to get all the glare out?
    >
    > thanks


    Oil paintings are a special case. They have a number of different
    reflective surfaces at different angles. I have not done many so take my
    comments with some skepticism.

    I have never had to try and work with the orientation of the filters on
    the light sources. I have always just had them aligned the same and working
    with the filter on the camera was enough. However I can see how you might
    get in a situation where being able to rotate the light source filters might
    be useful. The ones I used were held on with clips that could be moved, but
    never were moved. I don't know about what may be available today as my
    working experience was over 30 years ago.

    I suggest that you pay close attention to whatever David Littlewood has
    to say in this matter as he is the man on this kind of subject.

    --
    Joseph Meehan

    Dia duit
     
    Joseph Meehan, May 3, 2006
    #7
  8. Guest

    how far away should the polarizers be from the light source. i'm
    wondering if too close would burn the polarizers.

    thanks
     
    , May 3, 2006
    #8
  9. In article <fT%5g.420$>, george <>
    writes
    >>

    >Does this also mean that the lights have to be at the same power setting?
    >The thinking here is that all the lights I've ever measured the color temp
    >on change (slightly) at different power settings so that would mean that
    >you're getting different wavelengths of light.


    Yes, reducing the lamp voltage (and hence power) will lower the colour
    temperature, as will using a bulb of lower power rating. If it's really
    important to you, the temperatures can be corrected with CC filters.
    Your camera's WB correction cannot get it spot on if the two (or more)
    light sources are different. However, I wonder how far out the lamps
    would have to be before you would notice the effect. The great advantage
    of digital here is the instant feedback - you can compare the output
    with the original virtually instantly, and correct the illumination if
    necessary.

    David
    --
    David Littlewood
     
    David Littlewood, May 3, 2006
    #9
  10. Guest

    You might consider buying polarizing sheet material from someone like

    http://www.3dlens.com/

    Then you can make your own rotating filters. About $10 for an A4 sized
    sheet; they also have adhesive backed film that could be put on a sheet
    of glass or plastic.

    It won't matter how far the filters are from the lamps; what matters is
    how much of the illumination on the painting is polarized. If the
    plastic filters are too close to the lamps they'll burn.

    >From an optics standpoint, linearly polarizing the light from the lamps

    makes good sense in decreasing surface gloss effects from oil
    paintings. The polarization angles will depend on where the lamps are
    with respect to the camera's optic axis and the orientation of the
    brush strokes.

    Dave
     
    , May 3, 2006
    #10
  11. <> wrote in message
    news:...
    SNIP
    > i guess "reflection" was the wrong word since the paintings
    > don't actually reflect anything. but the surfaces
    > are shiny enough to produce glare that "milks out" the color.


    That *is* reflection of the lightsource, in the direction of the
    camera. It is (semi-)specular reflection to be more accurate. Since
    you want to eliminate that, you'll need to 'cross' the polarization of
    the lightsource and the lens filter for the reflection to become dark.

    > i tried using only the polarizer on my camera, and it was
    > virtually useless in eliminating glare. it only eliminated glare
    > from by placing the camera at an angle, but i have to shoot
    > my artwork straight on.


    If you only use a polarizer on the lens, then its efficiency varies
    with the incident angle of the light on the paint-surface and you'll
    only get some partial reflection suppression.

    Bart
     
    Bart van der Wolf, May 3, 2006
    #11
  12. I shoot for an arts publication and have to shoot art work on site a lot. I
    don't carry a lot with me so this is what I have done in these situations. I
    turn the room lights off and close the curtains. If there is any ambient
    light at all most digitals can handle it. Set the camera on auto and it will
    stay open as long as it needs. Shoot a test with a sheet of white paper and
    check your work. Shoot RAW if you can. In the computer make the white page
    look right and use the same settings on the work shot.

    This won't be good enough for all uses but is fine for newsprint and many
    other situations.

    --
    Thanks,
    Gene Palmiter
    (visit my photo gallery at http://palmiter.dotphoto.com)
    freebridge design group

    <> wrote in message
    news:...
    >i shoot my artwork. they are oils and there are lots of reflections.
    >
    > a pro finally showed me how to shoot artwork. he had polarizer filters
    > on both his lamps and his camera....he rotated his lamp filters until
    > he got as much glare/reflection out as possible, and then when he
    > fiddled with his camera polarizer, he eliminated all the glare. so now
    > i know what to do and what to get.
    >
    > i went to adorama here in nyc and asked to see their light filters. the
    > lamp polarizers were stationary, ie,,,they could not rotate. he said he
    > didn't have lamp polarizers on a rotating frame.
    >
    > my question is,,,,is this right. should they be able to rotate???,,, or
    > does it matter if i can rotate the lamp filters or not? IT CERTAINLY
    > MADE A DIFFERENCE when i watched the photographer. is it necessary to
    > rotate the lamp filters to get all the glare out?
    >
    > thanks
    >
     
    Gene Palmiter, May 3, 2006
    #12
  13. wrote:
    > how far away should the polarizers be from the light source. i'm
    > wondering if too close would burn the polarizers.


    Sure will, trust me.... don't ask how I know.

    >
    > thanks


    --
    Joseph Meehan

    Dia duit
     
    Joseph Meehan, May 3, 2006
    #13
  14. Guest

    Bart van der Wolf wrote:


    > Since
    > you want to eliminate that, you'll need to 'cross' the polarization of
    > the lightsource and the lens filter for the reflection to become dark.


    > Bart


    can you explain? thanks
     
    , May 3, 2006
    #14
  15. Guest

    my 4 megapixel gets me 5.5" images at 300dpi. they are good enogh for
    brochours
     
    , May 3, 2006
    #15
  16. <> wrote in message
    news:...
    >
    > Bart van der Wolf wrote:
    >
    >
    >> Since
    >> you want to eliminate that, you'll need to 'cross' the polarization
    >> of
    >> the lightsource and the lens filter for the reflection to become
    >> dark.

    >
    >> Bart

    >
    > can you explain? thanks


    Look through the lens+polarizer to the polarizers in front of the
    lamps, you need to turn the lens polarizer till the lamps look
    darkest. In that position the two planes of polarization are
    perpendicular to each other, or crossed. This assumes both lamp
    polarizers have the same polarization direction.

    Bart
     
    Bart van der Wolf, May 3, 2006
    #16
  17. Guest

    Bart van der Wolf wrote:

    > Look through the lens+polarizer to the polarizers in front of the
    > lamps, you need to turn the lens polarizer till the lamps look
    > darkest. In that position the two planes of polarization are
    > perpendicular to each other, or crossed. This assumes both lamp
    > polarizers have the same polarization direction.
    >
    > Bart


    so then i have to match up the lamp polarizers first? to do this, do i
    look through both lamp polarizers and match up to they're the lightest?


    thanks
     
    , May 4, 2006
    #17
  18. JD Guest

    wrote:
    > You might consider buying polarizing sheet material from someone like
    >
    > http://www.3dlens.com/
    >
    > Then you can make your own rotating filters. About $10 for an A4 sized
    > sheet; they also have adhesive backed film that could be put on a sheet
    > of glass or plastic.
    >
    > It won't matter how far the filters are from the lamps; what matters is
    > how much of the illumination on the painting is polarized. If the
    > plastic filters are too close to the lamps they'll burn.
    >
    >>From an optics standpoint, linearly polarizing the light from the lamps

    > makes good sense in decreasing surface gloss effects from oil
    > paintings. The polarization angles will depend on where the lamps are
    > with respect to the camera's optic axis and the orientation of the
    > brush strokes.
    >
    > Dave
    >

    Will the auto focus and metering be bothered by having a linear filter
    in front of the lens? I know in SLR's that have a semi-silvered mirror
    that putting a linear rather than circular polarizer will affect metering.

    Anyone know of a place that sells sheet polarzing material. The 3dlens
    site sells linear.

    BTW, Olympus OM (old film stuff) sold a polarizering filter for their
    T10 ring flash. It was comprised of two circular filters, one for the
    lens and one for the ring flash mounted together so the optimum glare
    reduction was already figured out.

    Jay
     
    JD, May 4, 2006
    #18
  19. ½ Confused Guest

    On 3 May 2006 01:26:12 -0700
    In message <>
    wrote:

    > i shoot my artwork. they are oils and there are lots of reflections.
    >
    > a pro finally showed me how to shoot artwork. he had polarizer filters
    > on both his lamps and his camera....he rotated his lamp filters until
    > he got as much glare/reflection out as possible, and then when he
    > fiddled with his camera polarizer, he eliminated all the glare. so now
    > i know what to do and what to get.
    >
    > i went to adorama here in nyc and asked to see their light filters. the
    > lamp polarizers were stationary, ie,,,they could not rotate. he said he
    > didn't have lamp polarizers on a rotating frame.
    >
    > my question is,,,,is this right. should they be able to rotate???,,, or
    > does it matter if i can rotate the lamp filters or not? IT CERTAINLY
    > MADE A DIFFERENCE when i watched the photographer. is it necessary to
    > rotate the lamp filters to get all the glare out?


    You may have to look around to find lamp stands where the lamp itself
    can be rotated, thereby rotating the filter. (Here in Los Angeles
    finding stands and brackets like that is a simple trip to Studio
    Depot, Film Tools, or similar store.)

    Jeff
     
    ½ Confused, May 4, 2006
    #19
  20. In article <>, JD
    <> writes
    > wrote:
    >> You might consider buying polarizing sheet material from someone like
    >> http://www.3dlens.com/
    >> Then you can make your own rotating filters. About $10 for an A4
    >>sized
    >> sheet; they also have adhesive backed film that could be put on a sheet
    >> of glass or plastic.
    >> It won't matter how far the filters are from the lamps; what matters
    >>is
    >> how much of the illumination on the painting is polarized. If the
    >> plastic filters are too close to the lamps they'll burn.
    >>
    >>>From an optics standpoint, linearly polarizing the light from the
    >>>lamps

    >> makes good sense in decreasing surface gloss effects from oil
    >> paintings. The polarization angles will depend on where the lamps are
    >> with respect to the camera's optic axis and the orientation of the
    >> brush strokes.
    >> Dave
    >>

    >Will the auto focus and metering be bothered by having a linear filter
    >in front of the lens? I know in SLR's that have a semi-silvered mirror
    >that putting a linear rather than circular polarizer will affect
    >metering.


    A circular polariser will be fine on the camera. All the "work" has been
    done by the time the quarter wave retardation layer does its thing.
    >
    >Anyone know of a place that sells sheet polarzing material. The 3dlens
    >site sells linear.


    Google throws up very many sources. Choose the one most convenient to
    you/cheapest. You definitely need linear polarising sheet on the lamps.

    David
    --
    David Littlewood
     
    David Littlewood, May 4, 2006
    #20
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