I'm an idiot, right?

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Brian Puccio

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I got a B+W circular polarizer (MRC) from B&H today. It was ordered at the end of February and was supposed to take 6-8 weeks, but it just got here now. So I open it up and look through it. Doesn't seem to do anything to the sky, so I rotate it a bit. Nothing changes. Weird, maybe I'm doing something wrong, maybe the glass isn't turning?

So I put a nice finger print on one side and a nice thumb print on the other. I look through it and hold the rear end (the part that would mount on a lens) and rotate the front ring again. Still, nothing changes and the fingerprint and thumbprint don't move relative to each other. It looks like this is one piece of glass.

I've never had a B+W circular polarizer, just Hoya models. They all had two pieces of glass and when you rotate the front ring, it increased or decreased the effect. This seems to be a single piece of glass with a front ring that rotates without doing anything. Am I missing something? Or did I just get a dud?

Everything on the packaging and the filter itself indicates that this is a MRC circular polarizer. I just want to make sure I'm not missing anything before I call B&H tomorrow and ask for a refund and thank them for wasting the past few months in getting it to me.

Thanks!
 
Random things to try:

- do you have polarized sun glasses? If you put the filter in front of them, and rotate it, there should be a difference.

- LCD monitors are polarized, if you put the filter in front, there should be a change when rotating. Same with LCD displays of any type.

- If you look at the reflection in a window, the filter should be able to minimize it. ( if the reflection is oblique. )

Hope that helps...
 
antiquark said:
Random things to try:

- do you have polarized sun glasses? If you put the filter in front of them, and rotate it, there should be a difference.

- LCD monitors are polarized, if you put the filter in front, there should be a change when rotating. Same with LCD displays of any type.

- If you look at the reflection in a window, the filter should be able to minimize it. ( if the reflection is oblique. )

Hope that helps...
Click to expand...

No sunglasses.

With my LCD, if I hold the filter in front and rotate the entire filter, I see a VERY pronounced effect. If I rotate just the front ring while holding the filter itself steady, I see no change at all.

If I look at a reflection in a window and rotate either the filter or the front ring, I see no change.

Juan Valdenebro said:
It should have the two surfaces you've seen in others before... And one of them should rotate... Yes, you should call them and ask...

Cheers,

Juan
Click to expand...

Great, I'm not a moron, I thought there should be two surfaces, or at least that how I understand circular polarizers to work.

antiquark said:
You can also use a mirror to test a polarizer. I will only reflect from one side (see video):
http://www.youtube.com/watch?v=6lVIo9C0NDA&feature=related
Click to expand...

According to this test, the circular polarizer works just fine. But how does this mirror trick help me when it doesn't change the sky?
 
antiquark said:
I think the sky polarization is dependent on the weather.
Click to expand...

I was at 90 degrees to the sun, where the polarizer should have had the most effect.

My Hoya model had no problem changing the sky, just this fancy B+W one that did nothing as I turned it. The sun went down otherwise I'd take pictures of the two of them held next to each other. The Hoya I could turn the front ring and change the amount of the effect. Turning the front of the B+W did nothing since it's not actually holding a second piece of glass. It's like they sent me half of a circular polarizer.
 
Polarizers are only one piece of glass as far as I know, if the ring doesn't rotate the glass when it's on the lens something is wrong.
 
Polas are two pieces of glass cemented together with pola material inside. The glass rotates as one single piece.

With circ polas, one direction polarises, the other does not. To see the effect, look from the lens side, not the outside.

Skies go dark when the sun is 90 deg from lens axis. Anything else is reduced effect.
Pale blue will do nothing to little. You need a decent blue to start with.

Polas kill reflections off green leafed trees.

Putting finger on it was a big mistake. Try getting them off the MRC surface now.
 
Brian Puccio said:
I was at 90 degrees to the sun, where the polarizer should have had the most effect.

My Hoya model had no problem changing the sky, just this fancy B+W one that did nothing as I turned it. The sun went down otherwise I'd take pictures of the two of them held next to each other. The Hoya I could turn the front ring and change the amount of the effect. Turning the front of the B+W did nothing since it's not actually holding a second piece of glass. It's like they sent me half of a circular polarizer.
Click to expand...

Different manufacturers choose different grating sizes for their polarizing material. The trade-off is between a very strong effect with more light loss, and a more subtle effect with less light loss.

Comparing a Hoya and a B+W that I've lying around, I see that the effect of the Hoya is much stronger than the B+W, but the light loss is also about a stop more..
 
Ah ha!

I may be an idiot (two pieces of glass, but they turn as one, etc), but the problem with the filter was the glass wasn't in all the way, so nothing was rotating. I pushed the glass in a bit more, it made a sickening snap sound, but looks alright still.

You're right, finger prints don't come off this easily.

But I'm back in business, when I look at the sky and rotate the polarizer, I can see the changes.

Thanks everyone!
 
The two-seperate-pieces-of-glass device you're talking about sounds like a variable ND filter.

Polarizers rotate as one. And remember: You only need a (more expensive) circular one if you need TTL metering or AF. Otherwise a linear one will work fine (or even better, effect can be slightly more pronounced, in my experience),
 
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