Can ND filter double as polarizing filter?

[ken_l3]

<p>I have a B+W ND filter (- 3 stop) that I use a lot. I use it to compensate for the fact that my camera (micro four thirds) has a flash syncro maximum of 1/160. One issue is that even with the ND filter attached, sometimes the sky is not blue enough. I thought ND filters are in substance stacked polarizing filters. But I don't think I'm getting any polarizing filter effect from my ND filter. I might if I can rotate the ND filter, but the ND filter doesn't have a rotating ring. Adding additional polarizing filter on top of the ND filter is not an option, as it will create a host of problems.<br>

So, can ND filters double as polarizing filter if you can rotate it and get the right angle? If not, are there ND filters that CAN double as polarizing filter with a rotating ring?</p>

 

[JDMvW]

<p>ND filters I have had have not been stacked polarizers, but neutrally tinted filters.<br>

Interesting. I would think that a non-variable ND filter cannot be, but I'm not sure whether the variable ones are just polarizers (in which case it would work) or whether they work some other way.</p>

[franklin_white]

<p>Think of it the other way around. A circular polarizer filter can be used as a very weak ND filter because it will reduce the exposure by two stops. </p>

[bob_sunley]

<p>Variable ND filters are stacked pol filters, hopefully good ones that stay neutral as they approach extinction. Regular ND filters should be neutral, available all the way to 10 stops. Yes you can use a single pol filter as a ND one, just orient it so there is minimal effect on polarized light from the sky, reflections, etc.</p>