Polarizing Filters

Discussion in 'Photography Beginners' Forum' started by rmh159, Aug 17, 2006.

  1. rmh159

    rmh159 TPF Noob!

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    I've used circular polarizing filters before however I never seem to QUITE get the strong blue skies that I've seen in other pics. Granted my experience has been with a P&S that had an adapter to put a polarizer over the lens but I'm not sure it was of the highest quality.

    I'm fairly sure I'm using the filter correctly and I know that the strength of the effect is related to how the filter is turned and the position of the camera / subject / sun.

    Just to verify can someone explain the technique used to get the darkest blue skies possible with a polarizing filter? Does the brand / coating of the filter impact this?

    Thanks
     
  2. Tiberius

    Tiberius TPF Noob!

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    Are you looking at pics straight out of the camera? If so, it's time to look at post-processing - levels and color balance for your specific complaint, but you might as well go all the way into looking at sharpening, noise reduction, cloning stuff out, the works.
     
  3. rmh159

    rmh159 TPF Noob!

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    This pic is a decent example

    [​IMG]

    You can see by the water that the polarizer is doing it's job and the effect seems strong however the sky doesn't quite show that.

    So you're saying that as long as I keep the circular filter turned to it's strongest amount and keep the sun about 90 degrees from the subject I'll be getting the most I can out of the equipment and the rest needs to be done in post-processing? That makes sense.

    Is there any specific process you'd recommend for post-process or just your typical Levels / Curves adjustments?

    Thanks for the response.
     
  4. Tiberius

    Tiberius TPF Noob!

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    It's a guess. As you pointed out, your polarizer is doing its job. For quite some time I stubbornly refused to learn GIMP/Photoshop, thinking that Proper camera technique could do everything. Unfortunately, just as getting the most out of film shots requries darkroom technique, I've found that 99 times out of 100 those "stunning" shots that I'm in amazement of had some touch-up work done afterwords to bring out the colors or contrast even more.

    I've always gotten away with the standard Levels/Curves adjustments myself, but my knowledge of Photomanipulation is at a high beginner level at best - I've only really been working with it for a couple of months. There may be better techniques that others know more about.
     
  5. AluminumStudios

    AluminumStudios TPF Noob!

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    In my experience a polarizer works best with really clear skies. If there is a thin layer of haze in the sky (even if the skies are still blue), the polarizer won't seem to deepen them as much.

    It can be tricky using a polarizer on a point-n-shoot because you can't always seen on the lcd screen when it's turned to the optimum angle to do it's job (which is different for every shot.)

    If you want darker skies though, a little post processing can definitly help.
     
  6. ksmattfish

    ksmattfish Now 100% DC - not as cool as I once was, but still

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    It looks like to me that the polarizing effect is stronger on the right side. You might have gotten a bit more effect if the lens was pointing more that direction. I agree though that there also may be something to do with the atmosphere that affects the way the sky appears.

    It's very possible to get navy blue skies using a pol without post-processing. This shot is Fuji NPS. Obviously I'm getting the polarizer fade from not pointing exactly the right way, but this is how it came out of the camera with a regular saturation/regular contrast print film.

    [​IMG]

    Here it is from digital. I can't remember what I did in post-processing, but I didn't mess with the sky color.

    [​IMG]

    Here it is from digital again, and the sky is darker than normal, and you can tell by the fade (wide angle) that I'm facing the right way, but I'm not getting the really dark, navy blue.

    [​IMG]

    Hmmm, looking at these together it seems that it may also have something to do with how close to the horizon the sky is (maybe haze like Aluminum said).
     
  7. Torus34

    Torus34 No longer a newbie, moving up!

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    Those of us in the smog-ridden north-east sometimes believe that the effects of polarizers are a myth. The darker the blue, the greater the effect. Incidentally, the same holds true working with orange and red filters in B&W film.
     
  8. Arch

    Arch Damn You! Staff Member Supporting Member

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    judging by the shot you posted it looks to me like you exposed for the sea..... this will cause the clouds to blow out and the sky to be pale...... sometimes this cant be helped in the flied if the forground is important to expose for.

    What i tend to do, is expose for the clouds.... if you get it right you can achieve a balanced image with just a few ps adjustments to the forground..... but it can go wrong if you expose for the brightest part of the scene and the forground becomes too dark....

    But using this technique you are more likely to achieve the type of blue saturation you want..... turning the polarizer before you shoot to get the best contrast is also essential. ;)

    This shot isnt a good example of blue saturation (because in England we dont often get blue skies!) but it shows what happens if you get the cloud exposure right, without too much underexposure to the forgound. The forground did need brightening in ps tho.

    [​IMG]
     
  9. LWW

    LWW TPF Noob!

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    Here's the key to great blue skies with a polarizer...

    ...make sure that either your right or left shoulder is pointed at the sun, or IOW you want the lens at a right angle to sunlight.

    LWW
     
  10. Unimaxium

    Unimaxium TPF Noob!

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    Like aluminumstudios said, the atmosphere can play a big part in how much of an effect the polarizer has. The blue light coming from the sky is polarized, but gray haze is not. Also, the angle at which you're taking the shot in relation to the sun can affect how much the polarizer will work. I think I remember reading once that the greatest polarization occurs at 90 degrees from the sun's axis. The easiest way to think of this is to make an "L" shape with your thumb and forefinger, and point your thumb towards the sun. Wherever your forefinger points will be where you'll find the strongest polarization (and remember that you can rotate your thumb around that axis 360 degrees and still get that polarization).

    And also, polarizers aren't the only thing that will help you get a deep blue sky. If you shoot later in the evening or early in the morning, you will generally get much stronger colors than if you shoot at high noon. This article provides a good example, and this article talks a bit more about how to get good colors.
     

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