Saturday, April 11, 2009

The Amazing Polarizing Filter

I've made a discovery! Well, OK, somebody else made the discovery - I'm just a slow learner. Years ago, when I was actively using my 35 mm SLR film camera, I had a collection of lenses, and for each of them I purchased a protective filter - usually just a UV filter. The main purpose of keeping these filters on the lenses was to keep the lenses from getting scratched. After all, it'd be a lot less expensive to replace a filter, than to buy a whole new lens!

For my new Canon DSLR, I have only a single lens, and I really didn't want to see it getting scratched. So, I bought a pair of filters; one a UV filter, and the other a circular polarizer. I always keep one of these on the lens at all times. But, to be honest with you, I hadn't been able to see these filters make any difference in the pictures. That is until now.

Yes, of course, I'd read about the use of these filters, and how they are supposed to help landscape photos look better. I tried them, but couldn't see the difference.

The other night, I put the polarizer filter back on. I tried looking West toward the sunset (my usual subject) and rotated the filter, but again, couldn't see any difference. I tried looking in the opposite direction from the sun (East), but, again, no difference. Just for the heck of it, I tried looking North and South. And, there it was!

At sunrise or sunset, when looking perpendicular to the direction of the sunlight, rotating the polarizing filter makes the brightness of the sky change drastically, without having much affect on the brightness of other things, like clouds and cactus.

The following two shots were taken just a few seconds apart. I'm facing North in these shots. I had the camera on a tripod so as to not move it between the pictures. In the first shot, I rotated the polarizing filter to make the sky look as bright as popssible. I also adjusted the the exposure time so the exposure would be taken at about - 1/3 EV. In the second shot, I quickly rotated the polarizer to make the sky look as dark as possible, and re-adjusted the exposure time to again take the shot at about -1/3 EV.

Take a look at the two shots. Notice how in the first shot, the clouds look dark gray against the bright sky, and in the second the clouds look white against the dark sky? Although it doesn't show up very well in these two minature pictures, the desert forground shows up much better, too, in the second shot.

Alright, on to tonights sunset. When I first went out to start taking pictures, the following shot shows what I saw when looking East -- storm clouds in the desert.

And the following shows what was happening in the West.

After a while, the sun broke through an opening in the clouds. The next shot was taken with the Fujifilm camera. Note the radials out from the sun. I like them.

The next shot was taken right after the previous one was, but was taken with the Canon. Notice that the radials are absent. I don't have a good answer as to why this is, but I just remember the fact when I'm shooting. If I want to see the radials, I shoot with the Fujifilm camera. If I don't, I shoot with the Canon.

And finally, a few minutes later, here is what happened when the sun went down a little lower, below the bank of clouds.

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