LA Loc: Little Rock, AR

Recently, I was trying to adjust my polarizer angle to reduce reflections from leaves etc., in a scene with lots of vegetation. A nearby professional saw me struggle with deciding which position was best and said, "If it's hard to see the best angle, raise straight up and adjust the filter so the blue sky is darkest...that will also be best for reducing reflections in your scene." My reaction was that it would be nice if it were true, what he said, but I was skeptical. What do others think? Maybe there is an accepted solution to this problem, but I have been unable to find it. I haven't had the time to really test his idea, but will do so. Just hoping feedback from you guys will give me some ideas to try.

Gene51 Loc: Yonkers, NY, now in LSD (LowerSlowerDelaware)

Right angle to the sun. Looking through the viewfinder without sunglasses on is the only way I know how to do this.

rmalarz Loc: Tempe, Arizona

Fortunately, my CP has some manufacturing marks on the ring surrounding the glass. I simply move the mark to where I know I get the most effect. It makes sense, but realize the CP work optimally at one particular angle from the sun. As one moves 90 degrees from that angle, the effect of the filter is minimized.

In the case you sited, you may have been looking at a scene that was at that particular angle where little or no effect is seen.
--Bob

LA Loc: Little Rock, AR

Thanks, Gene & Bob.
You have helped a lot to organize my thinking.

What we know is that light scattered by the atmosphere (haze and blue sky) has the greatest polarization when looking at right angles to the Sun, and the polarization is perpendicular to the line between the Sun and the spot you are looking at. That info is very helpful in darkening the sky or eliminating haze.

But light scattered from dielectrics (non-metallics, the surface of water or leaves, say) is most greatly polarized when its angle with the surface is 34 degrees for water (and similarly for plant surfaces), and the polarization direction is parallel to the surface. So the polarization direction varies all over the place for plant surfaces depending on how the leaf is oriented and it's a bit hard to see how the rule for atmospheric scattering also holds for leaf reflection.

What IS clear is that, if the plant is illuminated by direct sunlight (i.e., not an overcast day), the direction of polarization from plant-reflected light is perpendicular to the plant-to-Sun direction, and the strongest polarization will be when the Sun is approximately at right angles to the direction you are looking (but related to greatest pol for reflection, so not exactly 90 deg), AS GENE & BOB SAID.

If it is cloudy, there is no general rule because plant surfaces at all kinds of angles will reflect the diffuse light from the sky so there will be no preferred pol direction. That was the situation I faced a couple days ago, which explains why I was not able to see any preferred polarization as I turned the polarizer...there was no preferred polarization.

RWR Loc: La Mesa, CA

This proves the myth that a pro knows more about photography than a serious amateur. Maximum polarization may or may not be best for the scene. If changing your position for the best polarization results in an unfavorable perspective, and you cannot modify the light, your only choice is to return when the lighting is better, or forego the shot.

Wanderer2 Loc: Colorado Rocky Mountains

In my experience the pro is basically correct. Although the effect is greatest at right angle to the sun that often isn't possible and there will still be some effect at less than right angle, the effect progressively lessening as the angle lessens. At least that's my experience and I use polarizers extensively for landscapes.

John N Loc: HP14 3QF Stokenchurch, UK

An imaginary line across your shoulders should point towards the sun. If the sun is at 45° to the horizon, bingo, you've got the best you'll get. Variations from this reduce the effect but do not eliminate completely.

The pro was probably correct but I'd be wary of pointing the camera skywards in case you get an eyeful of sun.

billnikon Loc: Pennsylvania/Ohio/Florida/Maui/Oregon/Vermont

For max rendering, 45% to the sun.

mborn Loc: Massachusetts

lsupremo Loc: Palm Desert, CA

Does that mean that you need to tweet the adjustment as you move off of 90 degrees?

quote=Gene51]Right angle to the sun. Looking through the viewfinder without sunglasses on is the only way I know how to do this.[/quote]

camerapapi Loc: Miami, Fl.

What about opening 2 stops from meter reading for maximum polarization? Understand that still the 90 degrees to the sun rule applies.

John_F Loc: Minneapolis, MN

Light as it passes through the atmosphere (and relecting off water droplets and ice crystals) takes on some degree of polarization. When this light reflects off orher surfaces, such as leaves and flower petals, it takes on a second level of polarization. I have found that adjusting the CPL on a leaf or petal brings out the vein and surface detail. If the sky is not in the leaf & petal scene, the sky polarization is immaterial.

AlfredU Loc: Mooresville, NC

Yes, the pro gave you a good tip. Whatever polarization effect you did or did not have would be easier to see looking at sky and clouds than looking at small and subtle reflections from leaves. Seem straight forward to me.

Bullfrog Bill Loc: CT

If you maintain a constant angle to the sun as you raise the camera, he is absolutely correct.

rbmitch123

Not in response to the question but related.
I have trouble adjusting(reaching) my polarizer with the lense shade hood on. Ideas? Techniques that work?