Narrows

Other than size, is there any difference in certain Polarizers?

Carl D Loc: Albemarle, NC.

Don't buy a cheap one.

346pak Loc: Texas

If you look at some of the testing done on polarizers, they do show different results. For the most part you do get what you pay for as the more expensive filters will typically have more or better coatings on them which can give better results.

camerapapi Loc: Miami, Fl.

During the film era and especially when shooting slide film I used polarizers regularly. Now with digital the use is not as common as it used to be because except to eliminate reflections from a non metallic surface I am pretty satisfied with the results I get with proper exposure to darken the sky.
All polarizer filters use the same patent from Polaroid but they differ in the way they are constructed. As has been said, some filters are better than others depending on how much we pay.
I have old polarizers from the film era and they perform to my satisfaction when I use them.

Narrows

:thumbup:

Narrows

:thumbup:

Narrows

:thumbup:

Narrows

Loud an' clear

Armadillo Loc: Ventura, CA

Narrows,

There are differences in the quality of manufacture and materials used to make the filter components. The glass, plastic, attachment rings, etc. For the filtering material they all perform in the same manner, they absorb non polarized light.

You can purchase cheap polar filters and maybe they will perform well on your camera/lens system, maybe not. You can purchase a very expensive one and they will perform up to expectations, but a lot of your money will be pure profit. You can shop for the middle of the road price range and be pretty sure all will perform very well.

There are two basic types of Polar Filters.
1. A fixed Polar Filter that attaches to the front of your objective lens. Fixed in the sense it cannot be adjusted for effect and may alter the auto focusing and exposure meter of your digital camera systems. Often this filter can slide vertically, or horizontally in front of the objective lens.
2. A Circular Polar Filter (CPL) that can be rotated for adjustment effects and because of its uniform coating works well with digital cameras.

Because of the initial cost of the filter you may want to look at a CPL system that uses a "Filter Holder" frame, this system allows you to purchase one filter and then adapter rings to adapt to all your lenses and their objective filter threads. In other words one filter fits all lenses with adapter rings.

An important thing to know about polar filters is that they perform best at 90 degrees to the sun; with the CPL you can adjust the effect of the filter by turning the filter ring and balance the effective filtration across the scene. If you were dealing with window display reflections, or rippling water reflections you can control how much reflection is captured in the scene.

Michael G

PS A neat test with a CPL filter is to hold one up to your eye, facing your computer monitor, and rotate the filter with your hand. See how it works.

MG

f8lee Loc: New Mexico

Michael, this is incorrect - the "circular" in the phrase "circular polarizer" has nothing to do with the shape of the filter.

CPs, which came into existence some time ago (20-ish years?) polarize light with a different kind of foil - I can't explain the physics offhand but in essence they somehow "twist" the photons in some manner. The upshot is that they do not interfere with the auto-focus and metering mechanisms in modern SLR/DSLR cameras.

Both Circular and Linear polarizers can make the blue sky darker or reduce reflections (depending on their relative angle to the light source) - they are the same in this respect. In the "old days", when there were only linear polarizers (though nobody called them that since there was nothing else anyway), they were sold in dual-ring mounts that enable you to spin the filter while it's attached to the lens to get the desired effect. In other words, your point #2 was/is true for both linear and circular polarizing filters.

I believe your point #1 relates more to ND (neutral density) filters, particularly graduated NDs - where the midline of the filter can be positioned at a point in the scene that is not necessarily the middle of the image. But that has nothing whatever to do with polarization.

And the reason a polarizing filter (linear or circular type) will cause an LCD display to "black out" as you rotate it in front of the display is because the way an LCD display works is by passing the light through a polarizing filter itself - so when the filter on the display's effect is at 90 degrees to the one in your hand effectively all the light is blocked.

rgrenaderphoto Loc: Hollywood, CA

I made the mistake once of buying an expensive lens and a cheap polarizer.

boberic Loc: Quiet Corner, Connecticut. Ex long Islander

Ditto.. Either Hoya or B+H

Narrows

Great advice, I appreciate it. I have used CPL for years but just recently asked if there is a quality difference. I will keep your comments in mind. Look at the computer top...interesting. Gracias

Snowboss Loc: Vernal, Utah

I use high end B+W

Armadillo Loc: Ventura, CA

f8lee,

I am going to disagree with your rebuttal.
'the "circular" in the phrase "circular polarizer" has nothing to do with the shape of the filter.'

The circular in CPL has everything to do with round polar filters. This is what enables the filters to rotate around the central axis of the objective lens element.

"CPs, which came into existence some time ago (20-ish years?) polarize light with a different kind of foil - I can't explain the physics offhand but in essence they somehow "twist" the photons in some manner."

I haven't heard of this before.

"The upshot is that they do not interfere with the auto-focus and metering mechanisms in modern SLR/DSLR cameras. "
Today the CPL filter will not interfere with the auto-focus, or exposure metering of the digital camera because the filtering material is all one density. Years ago (when film was the 'In' thing and most cameras did not have auto anything the graduated Polar Filter was somewhat useful. The filter could be moved laterally across the objective lens in the same way as a graduate ND filter can today. Where the interferrence comes from in graduated anything is the transition area between no filter and full filter.

Michael G