Polarizing - an experiment

A circular polarizing filter was added to my lens as a means of protection, instead of a neutral density filter. After all, what does a neutral density filter add except protection for your lens. The reasoning was to use the polarizer and take the enhanced clouds and sky, not having to mess with a lot of filter swaps. I was happy with the results and never did any testing until a beautiful rainbow was seen by naked eye but not by viewfinder or camera. Revelation: it must be the filter! This calls for a test.

Four sets of images were taken from a tripod. First was polarizer at minimum effect, second was polarizer at max effect, and the thrid was polarizer removed.

Results with aperture priority same ISO, same zoom and auto focus showed a variation in exposures. OH HO! Sets of exposures were typically ?, ¼, and 1/20. In the photo above, exposure for the left image was 1/30 with polarizer and 1/125 ( a 2 stop difference) for the right photo without the polarizer. However, the left hand photo is a nicer image with more contrast and ?pop?. So we see is a sacrifice of speed for quality.

Conclusions for me: 1. Go for quality. Stay with the polarizer unless you see a rainbow, then if one appears, rotate the filter to maximize rainbow or remove the filter. 2. Remove the filter if you need extra speed, after all in low light there will be little sunshine. 3. Otherwise enjoy the enhancements derived from the polarizer.