Using polarizers as ND filters

tsk1979

I was wondering is there a 58mm polarizer available on which you have a 58mm thread so you can attach another polarizer.
this would enbale me to reduce the light entering based the angle between the polarizers. So I can have a almost 0 stop to infinite stop ND filter. Great way to take waterfall pics in broad daylight.
Anybody tried such a contraption?

Manfr3d

tsk1979 wrote:

I was wondering is there a 58mm polarizer available on which you have a 58mm thread so you can attach another polarizer.
this would enbale me to reduce the light entering based the angle between the polarizers. So I can have a almost 0 stop to infinite stop ND filter. Great way to take waterfall pics in broad daylight.
Anybody tried such a contraption?

In theory yes, but a polarizer filters dont darken a picture uniformly.
It filters light by the angle it hits the reflecting subject. Thats why
a ND filter produces a different (uniform) darkening effect than a Polfilter.
Stacking two Polfilters will give you (in theory) a non uniform distribution
of light in your picture depending on the light that reflects off your subject
and on how strong you filter with 2 pol.

This is only theory, but in "good" lighting you might not notice it in your
pictures. Darn, I'll probably go out and try it - I want to know it 4 sure :

ziggy53

tsk1979 wrote:

I was wondering is there a 58mm polarizer available on which you have a 58mm thread so you can attach another polarizer.
this would enbale me to reduce the light entering based the angle between the polarizers. So I can have a almost 0 stop to infinite stop ND filter. Great way to take waterfall pics in broad daylight.
Anybody tried such a contraption?

You are likely to notice color control problems when two polarizers are stacked and used as a strong effect. BW might be interresting.

There is a variable ND filter available, if you're interested.

http://www.singh-ray.com/varind.html

ziggy53

tsk1979

ziggy53 wrote:

You are likely to notice color control problems when two polarizers are stacked and used as a strong effect. BW might be interresting.

There is a variable ND filter available, if you're interested.

http://www.singh-ray.com/varind.html

ziggy53

singh-ray is pretty expensive, so I thought i would try the 2 polarizer thingy Its bound to be interesting, and as for color correction, I think using RAW may enable me to fix the colors if its WB related

ziggy53

tsk1979 wrote:

singh-ray is pretty expensive, so I thought i would try the 2 polarizer thingy Its bound to be interesting, and as for color correction, I think using RAW may enable me to fix the colors if its WB related

By all means try it, and let us know your impressions. Because of how polarizers are manufactured, results will vary and you might wind up with something very usable.

Just be aware that the color problems are usually not uniform across the frame, and the problem may vary considering the source of light and the angle from the source.

Camera metering may also be affected, but that's about it for problems. It's not like anything will blow up.:D

ziggy53