Polarising Filters in Action

[etherial]

I had a look in the library but found nothing on filters. I wonder if we shouldn't add a chapter in the gear section about filters??

I thought this video was quite a good demonstration of what a polarising filter does.

http://vimeo.com/24839406


http://vimeo.com/24839406

[colinbm]

Great thanks.
Col

[David W]

Thanks for posting that video Mic. It was interesting to see how a CPL makes so much difference.

Regards

[ausguitarman]

Thanks Mic :th3:.

Been wondering about CPL's myself lately :).

[Analog6]

And there is a good article in May Better Digital Camera

[arthurking83]

good demo with only one small nitpick!

Polarisers do have a small effect on colour.
In the video the woman explains somewhere the static studio scene that it darkens the image in 'only one direction' and doesnt' affect exposure or colour. But she fails to do the proper test in that the CPL should have been taken off the lens to show if the is or isn't any change in colour in the scene.

Note if you have a polariser of some description it will almost certainly have a very light hue of colour in it;s make up.

I have three or four and the different colours(or hues) that I've seen in polarisers have been either green or red(that I have).
Your experience may vary.

If you use Auto WB in your camera, the camera may try to compensate for WB by adjusting itself to suit the scene as you've created it. So that if you place a reddish polariser in front of the lens, the camera may adjust itself into the green channel, and conversely if you add a greener polariser in front of the lens.
if I set the WB to a static value(say Sunny/Daylight) then the more red polarise produces a slightly magenta cast to the images, and so on for the slightly more green polariser filter.
The differences are subtle and need to be seen in a direct side by side comparison.
But my experience is that polarisers do affect colour in some slight description.

if I find my test shots(done many years ago) I'll post them up.

FWIW, in terms of quality: I have a two hundred dollar polariser and a much older $40 polariser from about 15 years ago, and I'm yet to see any difference in quality from the two extremes(other than the previously mentioned colour differences).