Q) A friend told me about a polarizing filter that imparts color to the image. Where would you use this kind of filter? Does it make sense to use a filter like this if you’re photographing in digital and can add color in Photoshop?
A) It’s always better to get the best capture from the start because then you have more options and more power in your image-processing software. Your friend was probably talking about the blue/gold filter from Singh-Ray (www.singh-ray.com) or the gold/blue filter from Cokin (www.omegasatter.com). By turning the filter, you can bias an accentuated color from an overall gold hue to a blue in certain areas of the image. This technique is most effective toward sunset or at sunrise, with a lot of water and reflections, where the exaggerated hues don’t look out of place. At other times of day and in some environments, the colors can look garish and artificial. Always use a tripod with this filter because it will cause the loss of a couple of stops of light, a problem that’s accentuated when shooting in low-light conditions. Between the polarization and the unusual colors, the effect of this filter isn’t easily duplicated in Photoshop.
These sunrise images were taken at Mono Lake, California, using a Canon EOS-1Ds MKII with an EF 24-105mm lens (55mm). The one on the left was taken without any filters at an exposure of 1/2 second at ƒ/11. The rose-colored image at the right was taken with the Singh-Ray Gold/Blue Polarizer at an exposure of 1 second at ƒ/11.