Polarizing filter ok for long time exposures ??

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I'm doing night photography. In order to get more saturated colors, I'm thinking of using a circle polarizing filter...

What do you think ? Would it be efficient ?

Thanx for your contribution !


-- Bruce Barelly (barelly@club-internet.fr), April 25, 2001


I doubt that it would be of much use unless you had shiney material in your composition and needed to cut the reflection of whatever light was present.

I think that a greater problem will be reciprocity failure. You'll have to use CC filters to obtain the natural colors of your subject. I don't know of anyone who has done the color calibration work for very long exposures.

Good luck. Bruce

-- Bruce M. Herman (bherman@gci.net), April 25, 2001.

Bruce: If you already have a circular polarizer, fine but buying one for use with a view camera is a waste of money, unless of course you plan using the CP also for a 35mm which requires it. Regular polarizers do just as good a job. As to the saturation of the colours when using polarizers that is only because the polarizer suppreses reflections from the object's surface. The reflections from a leaf for example will prevent you from seen the leaf in full detail. This principle applies day or night as long as there is an object that can reflect light, and a light source which can cause the reflection.

-- Julio Fernandez (gluemax@ora.auracom.com), April 26, 2001.

The other contributers have assumed that you're intending to do night landscapes or the like. I suspect that you're after cityscapes with car trails and bright neon lighting, right? If that's the case, a polarizer won't help one little bit. A polarizer will only increase the saturation of reflective surfaces, not self-luminous objects like lights.
The way to get good saturation of neon signs etc., is to get the exposure just right, and this means a lot of experimentation, or the use of a spotmeter and a good knowledge of your film characteristics.

Just a suggestion, I'm not sure if it's been done before. Expose your cityscapes through separate red, green, and blue filters. That way, you can get absolute control over the colour balance, or control the relative brightness of the different coloured lights.

-- Pete Andrews (p.l.andrews@bham.ac.uk), April 26, 2001.

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