The following photos of the floor in my lounge room show the effect of using a polarizing filter.
They also confirm that this filter is a circular polarizing filter: linear polarizing
filters are reversible, so it doesn't matter which way round you hold them. With a circular
polarizing filter, holding them the wrong way round produces changes in colour, but doesn't
eliminate reflections.
Polarization has profound effects on the exposure and the colour balance. I took the photos
below with automatic colour balance, to see what compensation the camera thought
appropriate, and then changed the colour balance to 5000° in each case in postprocessing. I
didn't do any other postprocessing.
All photos were taken with an Olympus E-30 camera with Zuiko Digital ED
12-60mm F2.8-4.0 SWD lens at 60 mm. Some people claim to have trouble focusing with
polarizing filters. Despite the relatively low light conditions, I didn't have any trouble
with these shots.
Polarizing filter in “polarized” mode. Colour temperature 3654°, 1.3 sec, f/8.0
(EV 5.6). This is two stops more exposure than the previous image, and a colour temperature
difference of 1400°
Polarizing filter reversed, at the other extreme of colour change. Colour temperature
4238°, 0.3 sec, f/8.0 (EV 7.7), 1600° less than the previous image.
