Filters, when and how

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  • 03-13-2009, 09:13 PM
    tayl0124
    Filters, when and how
    Okay as seen in my sig I have 2 filters, a ring style Polarizer( I believe that is what it is called) and a Skylight filter. When do or would I want to use these?? I have been told that with a dslr the only filter widely used is the polarizer. Thank you in advance for your answers.
  • 03-13-2009, 11:37 PM
    Frog
    Re: Filters, when and how
    Some use the skylight or uv filter as lens protection and many of us say it isn't necessary and that its only a lesser quality piece of glass in front of your good lens glass.
    The polarizer is used to reduce glare. Put on a pair of polarized sunglasses and you'll see the effect which cannot be re-produced with editing. Used mostly to make skies bluer and put detail in clouds and to reduce glare off water.
    A neutral density filter is also a good idea.
  • 03-14-2009, 02:37 AM
    Didache
    Re: Filters, when and how
    Further to frog's answer, the polariser is especially useful for landscapes and seascapes where the sun is very bright and there are some clouds. It has the effect of darkening the sky and making the clouds really pop. It is not something I use very often - but it does help to prevent the washed out looking images that you can get in the bright part of the day.

    Mike
  • 03-14-2009, 12:16 PM
    readingr
    Re: Filters, when and how
    Polariser for landscapes, seascapes, and skiing. It enhances colour and contrast and stops glare from sea, water, or snow.

    Some say that ND grads are useful for landscapes but this can be done using multiple exposures and then bringing them together in PP.

    The Skylight I only use in dusty or raining conditions so that I only wipe the filter with a microfibre cloth rather than the lens. The rest of the time its in its case.

    Roger R.
  • 03-14-2009, 10:52 PM
    tayl0124
    Re: Filters, when and how
    as far as the ring polarizer, how is it actually used?? does turning the ring make big changes in the picture??? Haven't been able to figure this thing out yet. Maybe it is just a cheap filter. Inherited it from grandpa.
  • 03-15-2009, 11:36 AM
    Singletracklovr
    Re: Filters, when and how
    Quote:

    Originally Posted by tayl0124
    as far as the ring polarizer, how is it actually used?? does turning the ring make big changes in the picture??? Haven't been able to figure this thing out yet. Maybe it is just a cheap filter. Inherited it from grandpa.

    When looking thru the viewer rotate the PL filter and you should see the sky lighten and darken.

    There is a good chance your grandpa's polarizer is a linear polarizer and will cause your pictures to be darker or under exposed.
    Todays digital cameras mfg'ers recommend a circular polarizer.
  • 03-15-2009, 01:48 PM
    SmartWombat
    Re: Filters, when and how
    If it's an old polariser for film, then it may be a linear polariser (PL), not a circular polariser (PL-CIR). On a digital camera an old linear polariser could throw off the AF and metering.
    What is the labelling on the filter ?
  • 03-15-2009, 04:16 PM
    Frog
    Re: Filters, when and how
    This site shows the effect of using one. http://www.cs.mtu.edu/~shene/DigiCam...polarizer.html
    Probably other ones out there too.
  • 03-15-2009, 08:34 PM
    tayl0124
    Re: Filters, when and how
    SW, it is an albinar 52mm Polarizer
  • 03-16-2009, 01:08 AM
    danic
    Re: Filters, when and how
    Hold the filter up to the sky and rotate it. If it's a circular PL, you should see an effect. If not, it's linear.
  • 03-16-2009, 07:05 AM
    tayl0124
    Re: Filters, when and how
    danic, I haven't tried it outside, but I have tried to rotate it inside and it does get darker at certain positions.
  • 03-16-2009, 07:13 AM
    Singletracklovr
    Re: Filters, when and how
    Quote:

    Originally Posted by danic
    Hold the filter up to the sky and rotate it. If it's a circular PL, you should see an effect. If not, it's linear.

    I humbly disagree, I get more of a polarized effect with a linear polarizer vs a CPL.
  • 03-16-2009, 02:47 PM
    SmartWombat
    Re: Filters, when and how
    The visual effect of circular or linear is the same.

    Does it say "Super Albinar P.L" and a filter measurement in mm on the side?
    If so, then it is a polariser, linear.
    For film cameras not digital.
  • 03-16-2009, 07:38 PM
    freygr
    Re: Filters, when and how
    The UV filter is useful up in the mountains (Elevation 5000 feet or more). As for the Polarizer Filter the only difference between the circular an linear is that with the circular has unpolarized light exiting the filter. Just try the Polarization filter on you camera as SOME cameras don't care but others have problems with the linear polarization filters. If you have problems you will need to purchase the correct filter for your camera.
  • 03-16-2009, 08:14 PM
    SmartWombat
    Re: Filters, when and how
    Depends if there is a beam splitter in the AF or AE mechanism.
    That is usually susceptible to linear polarisation.
  • 03-16-2009, 08:33 PM
    tayl0124
    Re: Filters, when and how
    Quote:

    Originally Posted by tayl0124
    danic, I haven't tried it outside, but I have tried to rotate it inside and it does get darker at certain positions.

    Apparently it only does that when I am looking at my lcd monitor through it. I should get up from the computer chair every once and a while I guess.

    Smartwombat - it only says ALBINAR 52MM POLARIZER on it.
  • 03-17-2009, 02:45 PM
    another view
    Re: Filters, when and how
    If it doesn't say "circular" on it, it probably isn't.

    The amount of effect you can get with a polarizer depends on what angle you are to the light. If you're at 90 degrees, you'll be able to get the maximum effect (not that more is always what you want). Go outside on a sunny day and look thru the polarizer in a direction that would be 90 degrees between what you're looking at and the sun (IOW if it's directly overhead, look at the horizon). Now rotate the filter and you should see the effect. You won't get this effect on a cloudy day, however you still might see the effect on something like a waterfall.
  • 03-17-2009, 03:04 PM
    readingr
    1 Attachment(s)
    Re: Filters, when and how
    A picture is better than a thousand words or so they say:D

    Try a pano I took with a polariser attached (Linear on a DSLR) This is a pano across almost 270 degrees. The two darkened areas of sky are at 90 degrees to the sun.
  • 03-19-2009, 04:37 AM
    danic
    Re: Filters, when and how
    Quote:

    Originally Posted by Singletracklovr
    I humbly disagree, I get more of a polarized effect with a linear polarizer vs a CPL.

    I stand corrected :)
  • 03-20-2009, 08:03 PM
    freygr
    Re: Filters, when and how
    Quote:

    Originally Posted by Singletracklovr
    I humbly disagree, I get more of a polarized effect with a linear polarizer vs a CPL.

    I have to completely disagree. All a CPL is a linear polarizer with a unpolarizing layer on the camera's side of the filter. If you get a poorly made CPL you will have contrast and other optical problems which may reduce the effect.