A dumb question about filters.

[Blue_In_AK]

I've got this polarizing filter (I'm assuming that's what "PL" means on the ring). It kind of twirls around on my lens, looking sometimes grayish, sometimes more yellowish through my viewfinder. Can one of you who knows explain to me where I should twist it to for different effects? Like, for instance, if the sky is really glarish, and I want to reduce the brightness so I can get the best photo of whatever is on the ground, do I turn it to the cooler or the warmer? Is this the thing you use when you're taking waterfall pictures and you want to slow down the speed when the sun is out bright?

And how does this differ from a neutral density filter, and what do you use one of those for? (I don't have one, but if it's something that would be useful I might get one in the future.)

I was looking at the Singh-Ray Vari-N-Duo (very expensive) filter, which looks like it does some cool stuff, but if I don't even know the basics, it's probably beyond my skill at this point.

[JeffR]

1. No such thing as a dumb question. Little primer on polarizing filters here:

http://www.offrench.net/photos/articles/polarizing_filter.php

and here:

http://www.offrench.net/photos/articles/polarizer.php

[Blue_In_AK]

2. Thanks, Jeff.

That was really helpful. I didn't know that about the 90 degree thing or that a polarizer is not all that effective with overcast skies.

I see I'm going to be doing some experimenting.

[kentauros]

3. Here's a good short article on neutral density filters:

Using a Neutral Density filter

I recall talking to the salesman at the small shop where I bought my other equipment, and that the ND filter can be used like a polarizer, too, in blocking glare, cutting through the moisture in the air and so forth. Here's are two images taken with a Hoya ND8 filter. The first is unadjusted (other than size) and the second with some minor gamma/brightness adjustment:







To me, it really improves the contrast between the blue sky and the white/gray clouds. Without a filter, whether a polarizer or ND, the sky wouldn't look very impressive.

[Blue_In_AK]

4. Yes, that looks very nice,

and I like that the color is still true in the foreground, especially on the second one. It seems like once you learn how to use these, you could save a lot of computer time. And I just don't have the patience for doing all that bracketing and layer stuff.

I think the polarizer I have is going to come in handy in Nome next week. The forecast is for mostly sunny (and quite cold) all week long so the opportunity exists to really sharpen things up.