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**Adam** · 02-22-2007, 04:58 PM

Originally Posted by gorfmai

Both do polarize the same amount. I have seen some AF cameras that cannot focus / shoot for anything with a linear polarizer, others don't have such problems. As someone said, there's a lot of variables involved.

For whoever asked, how do they work -

Polarized light travels in "lines" - it is a linear wave form from ricocheting off metal, water, the ground, etc.

A linear polarizer has 2 peices of glass that are linearly polarized. When the lines on both elements are parallel (match up), the polarization effect is minimal, as lines of light can still slip through. When you rotate one element so the 2 peices are now perpendicular, you are basically cutting off every angle that polarized light can pass through the filter, hence the reduction in light. Only polarized light is affected, which is why at no time does your filter cut off ALL light (unless you happen to be surrounded by only polarized light waves!)

A circular polarizer does the same thing, except instead of lines, you have 2 slightly offset sets of coincentric circles.

You can do the same effect at home by finding 2 pairs of polarized sunglasses. Hold them both horizontal, minimal effect. But as soon as you start to rotate one...

Yes, I know I have oversimplified some of this, and its been a while since college physics. So please, no need to nit pick...

Can circular polarizers be used with mirror lenses?

02-22-2007, 04:58 PM	#12
Adam Administrator Site Webmaster Join Date: Sep 2006 Location: Phoenix, Arizona Gallery Photos: 48 Posts: 3,079	Originally Posted by gorfmai Both do polarize the same amount. I have seen some AF cameras that cannot focus / shoot for anything with a linear polarizer, others don't have such problems. As someone said, there's a lot of variables involved. For whoever asked, how do they work - Polarized light travels in "lines" - it is a linear wave form from ricocheting off metal, water, the ground, etc. A linear polarizer has 2 peices of glass that are linearly polarized. When the lines on both elements are parallel (match up), the polarization effect is minimal, as lines of light can still slip through. When you rotate one element so the 2 peices are now perpendicular, you are basically cutting off every angle that polarized light can pass through the filter, hence the reduction in light. Only polarized light is affected, which is why at no time does your filter cut off ALL light (unless you happen to be surrounded by only polarized light waves!) A circular polarizer does the same thing, except instead of lines, you have 2 slightly offset sets of coincentric circles. You can do the same effect at home by finding 2 pairs of polarized sunglasses. Hold them both horizontal, minimal effect. But as soon as you start to rotate one... Yes, I know I have oversimplified some of this, and its been a while since college physics. So please, no need to nit pick... Can circular polarizers be used with mirror lenses? __________________ Adam - Site Webmaster PentaxForums.com Usage Guide Enjoying the site? Help cover server costs by donating or getting some bumper stickers!