How to use a circular polarizer?

Hi everyone

I use 17-40 f4 and a 70-200 f4 most of the time. I have read numerous times that I should use a polarizer (outdoor natural light photography)

my problem is how to tell when I have the polarizer rotated to the correct position, at this point I can't tell.
Please enlighten me
Chuck Farrington

http://www.photo.net/photodb/folder?folder_id=350655

Hello Chuck,

The easiest way is to look through the lens as you turn. If you can't tell a difference after you've made it half-way around, then you're probably not in the right lighting conditions. You'll notice the skys turn a deep blue, whites warm up (as you turn further), and colors pop. The effect is so strong that it seems unlikely you wouldn't be able to tell.

You need direct sunlight, and be looking too much in the direction of the sun.

Hope this helps.

C. Farrington said:

Hi everyone
I use 17-40 f4 and a 70-200 f4 most of the time. I have read
numerous times that I should use a polarizer (outdoor natural
light photography)
my problem is how to tell when I have the polarizer rotated to the
correct position, at this point I can't tell.
Please enlighten me
Chuck Farrington

http://www.photo.net/photodb/folder?folder_id=350655

Click to expand...

--
http://jacemouse.com

"...and CAN'T be looking too much in the direction of the sun..."

Jace Mouse said:

The easiest way is to look through the lens as you turn. If you
can't tell a difference after you've made it half-way around, then
you're probably not in the right lighting conditions. You'll
notice the skys turn a deep blue, whites warm up (as you turn
further), and colors pop. The effect is so strong that it seems
unlikely you wouldn't be able to tell.

You need direct sunlight, and be looking too much in the direction
of the sun.

Hope this helps.

C. Farrington said:

Hi everyone
I use 17-40 f4 and a 70-200 f4 most of the time. I have read
numerous times that I should use a polarizer (outdoor natural
light photography)
my problem is how to tell when I have the polarizer rotated to the
correct position, at this point I can't tell.
Please enlighten me
Chuck Farrington

http://www.photo.net/photodb/folder?folder_id=350655

Click to expand...

--
http://jacemouse.com

Click to expand...

--
http://jacemouse.com

Chuck,

You will see the most results when the sun is at a 90 degree angle from the lens. While turning the lens more towards 0 or 180 degrees to/from the sun you will see less to no effect.

You can use it for many things, reducing glare off of water, glass and shiny surfaces other than metals, making the sky bluer and bringing color in your subjects.

You do however lose 1-2 stops of light.

KevinM

C. Farrington said:

my problem is how to tell when I have the polarizer rotated to the
correct position, at this point I can't tell.

Click to expand...

Chuck, point your index finger at the sun, and extend your thumb straight up (like you're making a "gun" with your hand). Now rotate your wrist. Your thumb points to all the places where you'll see the maximum polarization effect (90 degrees from the sun).

Try pointing your camera 90 degrees from the sun now, with the CP on the lens. When you rotate the CP, you'll see in the viewfinder the sky go from light to dark to light again. When the sky is the darkest, your CP is at its maximum effect.

When you turn your camera sideways, from portrait to landscape or vice versa, you'll have to re-adjust your CP.

CPs can (and should) be used for lots more than darkening skies, but that's the most common use.

--
Brian Kennedy
http://www.briankennedy.net/

Also, if you are using a lense without internal focussing (ie the filter moves when focussing) check that you have adjusted the filter for the desired effect after focussing.

Alternately, using a lense with internal focussing means you don't have to worry.

Like others have said only the sky at 90° to the sun is polarized, and reflections at certain angles. If you don't see a change in the viewfinder when rotating you don't have polarized light in your scene and the only thing the filter is doing is grabbing a few stops of light.

If the sun is low and you shoot with a wide angle lens it's possible to see the part of the sky that is polarized as a band:



10D + 17-40L + polarizer, near sunset.

--
Later,
Marty

Olympus: OM-1, C-2IOO, D-49O, D-4OZ
Canon: 1OD

http://science.widener.edu/~schultz/digipicts.html

Hi Brian

your explanation is most helpful, out of cuiriosity what are the other uses of a circular polarizer?
by the way, nice website, great photos
Chuck Farrington

Brian Kennedy said:

C. Farrington said:

my problem is how to tell when I have the polarizer rotated to the
correct position, at this point I can't tell.

Click to expand...

Chuck, point your index finger at the sun, and extend your thumb
straight up (like you're making a "gun" with your hand). Now rotate
your wrist. Your thumb points to all the places where you'll see
the maximum polarization effect (90 degrees from the sun).

Try pointing your camera 90 degrees from the sun now, with the CP
on the lens. When you rotate the CP, you'll see in the viewfinder
the sky go from light to dark to light again. When the sky is the
darkest, your CP is at its maximum effect.

When you turn your camera sideways, from portrait to landscape or
vice versa, you'll have to re-adjust your CP.

CPs can (and should) be used for lots more than darkening skies,
but that's the most common use.

--
Brian Kennedy
http://www.briankennedy.net/

Click to expand...

Thanks Marty

This is something that I will really have to watch for, I shoot alot of wide angle
Chuck Farrington

Marty Schultz said:

Like others have said only the sky at 90° to the sun is polarized,
and reflections at certain angles. If you don't see a change in
the viewfinder when rotating you don't have polarized light in your
scene and the only thing the filter is doing is grabbing a few
stops of light.

If the sun is low and you shoot with a wide angle lens it's
possible to see the part of the sky that is polarized as a band:



10D + 17-40L + polarizer, near sunset.

--
Later,
Marty

Olympus: OM-1, C-2IOO, D-49O, D-4OZ
Canon: 1OD

http://science.widener.edu/~schultz/digipicts.html

Click to expand...

Thanks Kevin

KevinM said:

Chuck,

You will see the most results when the sun is at a 90 degree angle
from the lens. While turning the lens more towards 0 or 180 degrees
to/from the sun you will see less to no effect.

You can use it for many things, reducing glare off of water, glass
and shiny surfaces other than metals, making the sky bluer and
bringing color in your subjects.

You do however lose 1-2 stops of light.

KevinM

Click to expand...

Thank you
Chuck Farrington

Jace Mouse said:

Jace Mouse said:

The easiest way is to look through the lens as you turn. If you
can't tell a difference after you've made it half-way around, then
you're probably not in the right lighting conditions. You'll
notice the skys turn a deep blue, whites warm up (as you turn
further), and colors pop. The effect is so strong that it seems
unlikely you wouldn't be able to tell.

You need direct sunlight, and be looking too much in the direction
of the sun.

Hope this helps.

C. Farrington said:

Hi everyone
I use 17-40 f4 and a 70-200 f4 most of the time. I have read
numerous times that I should use a polarizer (outdoor natural
light photography)
my problem is how to tell when I have the polarizer rotated to the
correct position, at this point I can't tell.
Please enlighten me
Chuck Farrington

http://www.photo.net/photodb/folder?folder_id=350655

Click to expand...

--
http://jacemouse.com

Click to expand...

--
http://jacemouse.com

Click to expand...

When I got my polarising filter for my S45 I did a few test shots. It seemed to darken the sky, which dropped allowed a slower shutter speed and as a result more colour to come from the other parts of the scene.

without



with



without (with a bit of the clip that holds it on in front of the lens - doh!)



with



http://dialspace.dial.pipex.com/town/pipexdsl/o/aoow37/polar/index.htm

I haven't tried the water effect, but it can remove the reflections off the surface, thus allow the water to become almost invisible. I have tried something similar and using the opposite effect to increase the reflections on my car window.



In fact, try looking at a shiny car through the filter, as you turn it, different parts reflect different amounts.

Richard

http://www.esses.co.uk/ (still under stylistic construction).

Below are pointers couple of web articles that show the use of a polarizer. "Circular" polorizers are required on most SLRs to support AutoFocus and Light Metering.

A key thing that confuses the use of polarizers is that ANGLEs are veryimportant. As others have commented, the angle to the Sun affects how much the Polarizer will darken the sky. Similarly the angle to between the camera and a reflection will affect how much glare you can cut out. Basically put, light gets polarized when bouncing off surfaces at certain angles and you can use this effect to cut out/control that light.

http://www.cs.mtu.edu/~shene/DigiCam/User-Guide/filter/polarizer.html

http://www.cliffshade.com/dpfwiw/polarizer.htm

C. Farrington said:

Hi everyone
I use 17-40 f4 and a 70-200 f4 most of the time. I have read
numerous times that I should use a polarizer (outdoor natural
light photography)
my problem is how to tell when I have the polarizer rotated to the
correct position, at this point I can't tell.
Please enlighten me
Chuck Farrington

http://www.photo.net/photodb/folder?folder_id=350655

Click to expand...

C. Farrington said:

Hi Brian
your explanation is most helpful, out of cuiriosity what are the
other uses of a circular polarizer?

Click to expand...

Thanks, Chuck. Basically, a polarizer is like a very fine screen of lines that allows light waves only going a single direction fit through. Circular polarizers are a little more complicated than that, and I'm not smart enough to explain or understand exactly how they work, but basically they are the same fine screen of lines with something called a "quarter wave plate" stuck behind the filter to adjust the exiting light back to something that won't screw with your camera meter or AF.

Anyway, the result of the filter is that certain light waves are blocked -- the polarized light. We see this light in the glare of the sky and off reflective objects like glass or water. Actually, anything outside in the sun can reflect more glare than you realize. Say, for example, you want to take a picture of the outside of a house. When the sunlight hits the house, it bounces all over the place and reflects back at you. If you use a polarizer, you can effectively cut the glare from the house, along with any reflections on the windows. So you end up with a much deeper, more saturated look with the polarizer, since you're blocking most of the scattered light that caused the glare. The same goes for shooting other subjects outdoors in the sun. Trees are a good example -- the leaves reflect more glare than you realize. Use a CP, and you get a much nicer, cleaner look to the photo. The greens of the leaves becomes much deeper. And when shooting around water, a CP will take the glare/sky reflection off the surface of the water. When shooting a wet frog or turtle, it will remove the shiny glare from the skin and make the colors richer.

Expert photographers even use polarizers in the studio. With care, a photographer can light a product with studio lighting, then use a polarizer to cut the glare from the product. Still too much glare? Then use a polarizing gel filter on the light in the vertical direction and another on the lens in the horizontal direction, and you're sure to keep glare to a minimum.

I'm sure that with practice and some more experience, you'll see just how valuable a polarizing filter is. Just walk around outside and turn the filter a few times to see what it does. The effect is often quite pleasing.

HTH!

--
Brian Kennedy
http://www.briankennedy.net/

take a look at a window or something that reflects... another way is to aim the little arrow on the polarizer to the sun.

here's an example (and yes that's the polarizer from my pocket-camera, my hands are not that big )

C. Farrington said:

Hi everyone
I use 17-40 f4 and a 70-200 f4 most of the time. I have read
numerous times that I should use a polarizer (outdoor natural
light photography)
my problem is how to tell when I have the polarizer rotated to the
correct position, at this point I can't tell.
Please enlighten me
Chuck Farrington

http://www.photo.net/photodb/folder?folder_id=350655

Click to expand...