What cameras need a Circular Polarizer? (Page 2): It is more dependent on the type of exposure and focus systems. If there is a half mirror involved, they cause bifrigent patterns in...

wdross Loc: Castle Rock, Colorado

nadelewitz wrote:

The explanations of linear vs. circular polarizes vary in clarity as to what is affected.
Is difference important because of autofocus, modern metering, or both?

It's clear a DSLR needs a CPL.

Is a CPL needed on a film camera with autofocus? Film cameras with some meter types but not others?

DSLR if using manual focus?

Etc.

It is more dependent on the type of exposure and focus systems. If there is a half mirror involved, they cause bifrigent patterns in the viewfinder that will drive one crazy. It can also affect the exposure and focus systems. And most modern mirrored cameras use half mirrored mirrors for there systems. The half mirrors let some of the light past through the mirror to a second mirror that sends the light downward to the exposure and focus systems while the rest of the light is directed upward to the viewfinder. With a solid mirror instead of a half mirror, linear polarizers will work. But as others have stated, circular polarizers with work with both types of systems so one does not have to worry about which type one has.

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

nadelewitz wrote:

The explanations of linear vs. circular polarizes vary in clarity as to what is affected.
Is difference important because of autofocus, modern metering, or both?

It's clear a DSLR needs a CPL.

Is a CPL needed on a film camera with autofocus? Film cameras with some meter types but not others?

DSLR if using manual focus?

Etc.

A circular polarizing filter is required on a digital camera to assure all functions of the digital camera work within the specs of the camera manufacture.

camerapapi Loc: Miami, Fl.

I use linear polarizers with my digital cameras all the time. Never an issue.

mborn Loc: Massachusetts

Pablo8 wrote:

I had both types Linear and CPL ages ago. With the onset of Auto-Focus and TTL exposure settings, the Linear filter became redundant, except for using in the light path of my Nikon Microscope, when doing crystal photography. A test for Linear or CPL if there are no markings on the mount. If the CPL is viewed and rotated in the reverse direction to normal mounting, no Polar' effect is seen. It only polarises in one direction.

Thanks

mikegreenwald Loc: Illinois

Further, all depends on whether the weather is cloudy or bright. Whether the weather is windy or calm also has an effect, in that a ruffled water surface is poorly reflective when the weather is windy. Whether you use a CP or Lp filter thus is also dependent on the weather.

Blurryeyed Loc: NC Mountains.

nadelewitz wrote:

The explanations of linear vs. circular polarizes vary in clarity as to what is affected.
Is difference important because of autofocus, modern metering, or both?

It's clear a DSLR needs a CPL.

Is a CPL needed on a film camera with autofocus? Film cameras with some meter types but not others?

DSLR if using manual focus?

Etc.

I'm not so sure about that, I purchased a linear Polarizer for my new lens, it is a 105mm so they can be quite expensive, I was able to get a Canon filter on ebay for a very reasonable price, I was in such a hurry to snatch this deal up that I did not pay attention to the fact that it was a PL filter which are commonly used by videographers, to my great relief it works just fine on my newer Canon body, both light metering and the focus systems work just fine using this filter.

Here is an article offered to me by another member when I asked the same questions regarding the difference of the two filters that will explain the difference and how they may effect the use of your camera. If you are purchasing a filter then I would recommend that you buy a CPL if you already have a PL then read the article and understand how a PL may effect your cameras light metering and focusing system and then go out and give it a try.

https://www.lindseyoptics.com/blog/linear-polarizer-vs-circular-polarizer-whats-the-difference/

DirtFarmer Loc: Escaped from the NYC area, back to MA

Since a CPL will work on any camera, there's no reason to acquire anything else. A CPL costs a bit more than a linear polarizer (if they still make them these days) because it has more components (a linear polarizer plus a quarter-wave plate), all of which have to have good optical surfaces. However the cost of a CPL is still fairly small compared with high quality lenses.

If you have an antique linear polarizer, there are some cameras you can use it on without a problem. You may see effects if you use it on a camera that uses a reflection from a dielectric surface to perform some function such as autofocus or metering. Many times the effect will be small so you may not even notice. If you use a linear polarizer on a modern camera you should be chimping a lot to check your shots.

JohnFrim Loc: Somewhere in the Great White North.

Pablo8 wrote:

A test for Linear or CPL if there are no markings on the mount. If the CPL is viewed and rotated in the reverse direction to normal mounting, no Polar' effect is seen. It only polarises in one direction.

A more interesting test/demo is to hold the polarizer(s) in front of your eye and look through the filter(s) at the reflected image of your eye behind the filter in a mirror. Then flip the filter around to look through it from the other face.

With a linear polarizer it does not matter which way you hold the filter, but with a circular polarizer in one orientation you will see your eye behind the filter (in the mirror) while when held the other way you won't.

CPLs are a combination of a linear polarizer on top of a quarter-wave plate, and it matters which way the pair is mounted on the camera (some filters have been shipped the wrong way around from the factory). The correct orientation of the CPL layers is that you should see your eye in the mirror when the threads of the filter are toward your face, as if your face were the camera.

nadelewitz Loc: Ithaca NY

More info polarizers, and a better way to tell if an unmarked one is linear or circular

http://www.bobatkins.com/photography/technical/polarizers.html

CatMarley Loc: North Carolina

rgrenaderphoto wrote:

All imaging cameras can benefit from a circular po... (show quote)

And that is why they will work better with a mirrorless which does both its focusing and metering directly from the sensor surface.

JohnFrim Loc: Somewhere in the Great White North.

CatMarley wrote:

And that is why they will work better with a mirrorless which does both its focusing and metering directly from the sensor surface.

What is the "they" -- circular or linear -- in your statement?

Apart from the unresolved (in my understanding) of a possible interaction with the anti-aliasing filter on the sensor, CPL will NOT work BETTER than a linear polarizer on a mirrorless camera.

CatMarley Loc: North Carolina

JohnFrim wrote:

What is the "they" -- circular or linear -- in your statement?

Apart from the unresolved (in my understanding) of a possible interaction with the anti-aliasing filter on the sensor, CPL will NOT work BETTER than a linear polarizer on a mirrorless camera.

Anti-aliasing filters are not used on most of the recent sensors, especially the mirrorless cameras. The mirror has always introduced difficulties because it had to divert light out of the direct beam and send it to a special device for metering and display it on a focusing screen for focusing. The older Bayer array of sensor elements introduced the moire problem which needed the anti-aliasing filters to suppress. The newer sensors use a more random array (more like film) which eliminates the need for filters and allows a sharper image. The mirror has always been a complicating factor. Simplifying the light path has removed some of the complications.

JohnFrim Loc: Somewhere in the Great White North.

So... Cat, are you in the CPL camp as necessary, or optional, with mirrorless cameras? I will assume you would agree CPL is NOT required.

CatMarley Loc: North Carolina

JohnFrim wrote:

So... Cat, are you in the CPL camp as necessary, or optional, with mirrorless cameras? I will assume you would agree CPL is NOT required.

It is necessary only if you need it to reduce glare, darken sky get rid of reflections etc. I used them routinely on my film cameras, not at all, that I can recall, on my DSLR's, and have not tried them on my mirrorless, because have not been doing landscapes or taken any trips lately. I think I only used the circular variety of polarizer. As I recall they were quite expensive - I have a half dozen or so different sizes sitting in my camera drawers. Have to check if they were linear or circular.

scsdesphotography Loc: Southeastern Michigan

E.L.. Shapiro wrote:

A linear polarizer, if employed on a modern digital camera, can cause various automatic functions like exposure metering and autofocus to malfunction and work inaccurately. A circular polarizer is required, when necessary, for full functionality on current digital cameras. Linear polarizers will work properly on older film camera. Circular polarizer are compatible on both kinds of cameras.