Circular Polarizer

I was recently chatting with a friend about imminent ownership of more camera hardware, and the subject of a circular polarizer came up. During the recent trip to Kiwi-land, I've had the object firmly stuck onto the front of my Zuiko 14-45mm lens for most pictures, and I thought it instructive to demonstrate its effect, by means of a simple before/after commercial. Here's the shot without the filter (or rather with the polarizer rotated so that it's somewhat useless).



And here's the effect of taking the picture again (with the same aperture width, shutter speed and ISO sensitivity) but with the filter getting rid of extraneous reflections off the water surface.



The little beast isn't only useful when taking pictures around water. Leaves have a nasty habit of shining (especially after they've been cleaned by recent rain), and so do asphalt on roads and window panes. Filtering out some of that light will either prevent the picture from being overexposed in the areas of reflection, or excessively compensated for by dialing down the exposure time and leaving the rest of the picture dark (a nasty habit of point-and-shoot toys which try to be smart).

The only drawback is that you lose a couple of stops of light, but for most outdoor images where the sunlight is bright enough, it doesn't pose a problem at all.