Why circular polarizers?

Started May 11, 2014 | Questions thread
chris102 Senior Member • Posts: 1,446
Re: Why circular polarizers?

Wheatfield7 wrote:

bosjohn21 wrote:

if this is miss information I am not aware of it as I have seen this explanation elsewhere it would be more helpful if you told me where its not correct then I would learn something

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John aka bosjohn21

A linear polarizer MAY cause a problem with the exposure, depending on where the exposure sensor is. Check your individual camera. If the exposure sensor is looking at the focusing screen and not buried in the bottom of the mirror box, it will not be affected by a linear polarizer.

The AF sensor is in the bottom of the mirror box, and depending on it's sensitivity, the maximum aperture of the lens in use the degree of polarization dialed in and the efficiency of the filter, it MAY affect the AF. All the linear polarizer does in this regard is reduce the amount of light getting to whatever sensor is buried in the bottom of the mirror box. If the AF sensor is sensitive enough to not be blinded, AF will be unaffected.

Luminous Landscape is speaking in absolutes, and in this they are wrong. Having said that, since it's well nigh impossible to buy a linear polarizer these days, the point is rather moot, but if you have a camera that meters off the focusing screen and tend to use a polarizer in situations that lens themselves to manual focus, and have a good linear polarizer sitting around, then you might as well use it rather than buying a circular polarizer.

Also, if you are using a mirrorless camera, there is absolutely no need to use a circular polarizer, other than that might be all that is available to you. I still shoot with linear polarizers that I bought for my view cameras and manual focus SLRS.

Luminous Landscape is often wrong on substantive factual material. Reichmann's forte is opinion.

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