Why is a Circular Polaizer ber than a Linear Polaizer?

[Mark500D]

Whist on holiday I fitted my old A series Cokin Linear Polaizer to my new 500D and got some great results. However, I read that a Circular Polaizer is better for DSLRs than a Linear Polaizer. I went into the local Camera shop with a view of getting a Circular one but they had none in. As I was upgrading to the P series Cokin filters I decided on getting the only Polaizer they had there, which was a Linear one. I bought it with a view of selling it later when I got a Circular one.

Having fitted the new P series, I still got aweosme results. Now I understand that Linear Polaizers have stright line running through them, hence the term Linear, and circular Polaizers have cirles running through them, hence the term circular. My question is, why is Circular better for DSLRs than linear?

[Hereford_EOS2]

Re: Why is a Circular Polaizer ber than a Linear Polaizer?

Quote: luminous-landscape.com

Linear polarizers are more effective and less expensive than circular ones. But circular polarizers are needed with just about any camera that has a through-the-lens metering system, or autofocus.

The reason for this is that both of these systems use semi-silvered mirrors to siphon off some of the light coming though the lens. If that light is linearly polarized it renders either the metering or the autofocus ineffective. This means that you're going to have to buy circular polarizers unless you're shooting with a pre-1970's camera.

[Mark500D]

Re: Why is a Circular Polaizer ber than a Linear Polaizer?

Quote: luminous-landscape.com

I am not too sure I understand. Sorry. My metering works (unless by ineffective you mean it is giving me the wrong info(and it is giving me the 2 stops down that I expected)) and my auto focus works fine also.

[SamFisher]

Re: Why is a Circular Polaizer ber than a Linear Polaizer?

I tried a Linear on my 300 f4 and it wouldn't AF.
Works perfectly with my CP.

Mike

[Mark500D]

Re: Why is a Circular Polaizer ber than a Linear Polaizer?

So, if my Metering is working, and my auto focus is working, can i continue using my linear polaizer, or, will i get better result from a circular one, or the same results?

[Nathaniel]

Re: Why is a Circular Polaizer ber than a Linear Polaizer?

I am interested in this as well. I have circular polarisers. My AF etc works fine with my cameras and lenses.

[Nathaniel]

Re: Why is a Circular Polaizer ber than a Linear Polaizer?

No member has volunteered any information on this question. Am I to assume that it doesn't matter which polariser filter one uses?

[Hereford_EOS2]

Re: Why is a Circular Polaizer ber than a Linear Polaizer?

Another quote:

Linear polarizers should not be used on DSLR cameras, because they can result in metering errors. Circular polarizers, on the other hand, are perfect for DSLRs and do not cause any metering issues due to their construction. Circular polarizing filters are essentially linear polarizers, with a second glass element attached to their back that circularly polarizes the light, giving accurate exposure results when the light hits the light meter. When the two elements are aligned at the right handle and orientation from the sun, the captured image could have more saturated colors, bluer skies, less reflections and higher overall contrast. Polarizing filters can also reduce haze, which is very useful for landscape photographers.
The effect of polarization changes relative to the sun. The maximum effect of polarization is achieved when the lens is pointed 90 degrees from the sun (in any direction).

[djguk47]

Re: Why is a Circular Polaizer ber than a Linear Polaizer?

Have a look at this article on Polarizing Filters HERE

and a quote from the article in the link......

Circular vs. Linear Polarizers. The circular polarizing variety is designed so that the camera's metering and autofocus systems can still function. Linear polarizers are much less expensive, but cannot be used with most digital SLR cameras (since these use through-the-lens (TTL) metering and phase detection autofocus).

David

[warrerj]

Re: Why is a Circular Polaizer ber than a Linear Polaizer?

I have nothing to contribute to the debate except to say if you're lookign for a circular polarizer give Mifsuds a ring. I picked up a perfect 2nd hand 72mm Hoya Circular Polarizer for £10. One of my local shops (jacobs) wanted £90 for a new 1 :-0

[Hereford_EOS2]

Re: Why is a Circular Polaizer ber than a Linear Polaizer?

NEW Hoya 72mm Pro1 Circular Polarizing Filter £47.96 from Amazon
NEW Hoya 77mm Pro1 Circular Polarizing Filter £60.34 from Amazon

[warrerj]

Re: Why is a Circular Polaizer ber than a Linear Polaizer?

OR £10 2nd hand but as new from Mifsuds :-)

[Hereford_EOS2]

Re: Why is a Circular Polaizer ber than a Linear Polaizer?

OR £10 2nd hand but as new from Mifsuds :-)

I always buy Hoya Pro1 new and refuse to pay Mifsuds £132.00 for a new 77mm Pro1 when I can buy it for £60.00 elsewhere.
Some of their "used" lenses are priced similar to new prices.
Example: Used Canon EF 24-70mm F2.8L USM £949.00, New price £989.00 from WEX or Jessops or only £952.32 from Amazon.