How Polarizers and ND filters actually work

Ian in London · Mar 29, 2018

ello all...

Having seen too many reviews on ND and polarizers that fail to explain the need to rotate the polarizers to make them work, I thought I'd make a short video on them.
They are so useful and make such a difference, so this comes complete with quick 30 second physics lesson on polarized light, and explains how reflections and glare are reduced by polarized (or polarised

) filters.

Hope it's useful!

Cheers

Ian

macoman · Mar 29, 2018

Excellent video!

Spot25 · Mar 29, 2018

Wellsi said:
ello all...

Having seen too many reviews on ND and polarizers that fail to explain the need to rotate the polarizers to make them work, I thought I'd make a short video on them.
They are so useful and make such a difference, so this comes complete with quick 30 second physics lesson on polarized light, and explains how reflections and glare are reduced by polarized (or polarised

) filters.

Hope it's useful!

Cheers

Ian

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Very informative, thanks for posting.

djiboi · Mar 29, 2018

Nice video. How do decide how much to rotate the polarisers? If you have an ND/PL filter, do you need to bother with the regular ND filters?

Irish-apple · Mar 29, 2018

Ians always cool videos thanks

Ian in London · Mar 29, 2018

djiboi said:
Nice video. How do decide how much to rotate the polarisers? If you have an ND/PL filter, do you need to bother with the regular ND filters?

Good point; at 5:20 on the video, you see me rotating the polarizer whilst looking through the camera's output via the phone's screen screen, and you see the reflections disappear at a particular spot. You can mark that spot on the upper point of the rotator, and that will always be the spot to rotate it to. (Even if you remove the filter and reattach it, the polarizer rotator will always work with that marked spot in the same loaction).
As for PL ND versus plain ND, well, it depends on what you're after. Polarized ND filters will block out refletions; that may be good, but may take away sparkle, depending on the shot. But, it could be argued that a polarized ND filter can have the polarization switched on or off by rotating it through a quarter turn, so yes, I guess you just have a polarized ND 8 and that's you set up for 90% of situations.....

Ian