this filter + that filter = (?)
 

Hello, (caution!!! maybe silly questions below.)
Do any of you guys/gals know of any tutorials or webpages that explain the dos and don'ts of using filters? I mean if I want the effect that a certain filter gives and also want the effect that another and yet another gives all in the same shot, can you just screw them all together (stack'em) and get all the effects together or do some cancel the others out, etc? Are there some basic rules that apply to doing something like this? Thanks.

There is an article here (click) on filters that illustrates some combinations. But, I'm not aware of one that covers mixing filters for effects.

Many folks use a warming filter along with an ND or polarizer. You can even buy a polarizer with warming filter built in. There are also some diffuser filters that have warming built in. I think you may need to experiment with different filters to get a certain 'look.' These days, it is often easier to make the video look like you want with editing software than to put a bunch of filters on the cam. About the only filters I can think of that their effect isn't easily duplicated in post are the polarizer and graduated filters.

You can always stack filters. You won't really "cancel out" anything, but when you stack them, you run the risk of vignetting at the corners. Also, since each filter cuts light by some factor (how much depends on the filter), you lose light the more filters you add -- your camera has to open up wider or increase gain to compensate. Finally, adding more glass in front of the lens increases the potential for flare and internal reflections.

So I agree for the most part it's best to do much of it in post. As Guy said, you can't duplicate a polarizer or ND effect in post. Most of the other filters, you can.

You could try these I found some time ago when researching filters:
http://www.geocities.com/cokinfilter.../polarizer.htm
http://www.colorado.edu/physics/2000...polarized.html
http://www.edbergphoto.com/pages/Tip-polarizers.html

Of these the Cokin filter site is the most comprehensive. Scroll to the bottom of the page to access pages describing other filters besides the polariser.