Weird polarizer?

[unpopular]

I got a cheap Sunpak circular polarizer for christmas. Right away, I noticed that it did not fully cut reflections, I was fiddling with it, and noticed that it also did not cut the light from my screen as I'd expect, but made it a deep royal blue. I looked at the ipad, same thing, deep blue. But i could still read the text, so it wasn't fully polarizing.

I looked at some other reflections, and again, noticed a deep blue. It did cut, but not as completely as others I've owned.

This makes sense, the filter is marketed at consumers, and the most important thing consumers want from a polarizer is to make the sky "deeper". It's actually kind of cool in this respect, even if it's not really that great as a polarizer, since it lets so much unpolarized light through ... only more blue.

Anyway, I flipped it around, and noticed that reflections shifted from yellow to neutral to blue.

That is actually kind of interesting, and I'm thinking that I could use it to selectively emphasize certain subjects like ice or water.

 

[DannyLewis]

I have a vivatar and a bower that does the same thing. With water and sky its really good I have yet try the other way though. I will next sunny day we have. The Bower cuts the reflection where the vivitar doesnt do that good. The vivitar FLD will shoot through tinted windows no matter how deep the tint is. kind weird. doesnt do good in flourescent like it should either.

 

[Mully]

^^^^^^ God Bless China.

 

[unpopular]

It's probably the same filter. It's kind of weird, you'd think selectively polarizing some wavelengths but not others would be more expensive to produce? I suppose it's going to impress people more, if they don't really know what a polarizer does other than make the sky look "better".

Mine has a simple retainer ring which I could remove and flip the filter over and use in reverse for it's "color coding" property.

I was not aware that an FLD was anything special - I thought it was just a color correcting filter? Are FLD's also a linear polarizers?

 

[unpopular]

^^^^^^ God Bless China.

I am pretty sure that this blueness is intentional to make it seem more effective than it actually is. I am also wondering if it's intended to be used in reverse. It's possible that this is some kind of glass used to color code polarization for analytical imaging. The Chinese factory they are coming from might have a good deal on this unique glass, and saw its "blue sky" benefits when used "improperly".

 

[480sparky]

Put it on your lens backwards, and see if you can image a black hole. :mrgreen:

 

[Buckster]

The description reminds me of the Cokin Varicolor Polarizer filters. I've got a red/blue one I bought and played with back in the 80's, but haven't used it in years. It's effects are WAY over the top, good for abstracts and such, which isn't really my bag.

 

[unpopular]

See, similar, but it only affects the reflected light which would be normally affected by a CPF, and is very subtle.

I think those variable color and variable ND's work with two linear polarizing filters?

 

[Buckster]

See, similar, but it only affects the reflected light which would be normally affected by a CPF, and is very subtle.

I think those variable color and variable ND's work with two linear polarizing filters?

Yeah, I believe so. Like I say, I haven't used mine in many years. Probably never even tried it on a DSLR, TBH.

 

[unpopular]

If yours was running green to magenta, I'd offer to buy it.

 

[DannyLewis]

FLD are for shooting in flourescent lighting.

 

[Majeed Badizadegan]

So what sort of color casts are you getting?

I'm looking at the B+W circular polarizer-- I'm just gun shy because I believe i want a stackable filter system.

 

[thetrue]

This thread inspired me to track down this sunpack "cpl" and indeed, it's quite different than - say - a normal cpl. I haven't flipped it yet, but the blue is mighty strong.

 

[unpopular]

So what sort of color casts are you getting?

I haven't used it yet since I don't have a lens that it will fit, I'll need a step up ring.

But from what I can tell, it DOESN'T really "cast", it appears grey like any other polarizer, maybe a bit "thin" but neutral. The coloring only is affected by non-polarized light. It's subtle, but is present and kind of odd.

 

[unpopular]

This thread inspired me to track down this sunpack "cpl" and indeed, it's quite different than - say - a normal cpl. I haven't flipped it yet, but the blue is mighty strong.

Hold it up to the screen in reverse and rotate it, it's super weird. It doesn't really cut the brightness of the screen, just shifts from blue to yellow. Same with all non-metallic reflections, doesn't cut them, just changes the color!