Desaturated

Johann Adler · March 28th, 2004, 11:34 AM

This polarizer topic is interesting. I remember those from Physics class in college. My professor told me that polarizers mearly pass natural light into one plane.

Also, concerning getting a light polarizer. According to the equation for a linear polarizer, the iradiance of light passing through it is always halfed. So this could only be useful in very bright scenes?

In practical usage, does a neutral density filter perform a similar function? Can/should they be used together? If no to both questions, then why don't the prosumer cameras include them?

Very interesting,

Jeff Donald · March 28th, 2004, 01:48 PM

Polarizers typically reduce the light by 1.5 stops to 2 stops of light. The saturation of colors is a result of reducing reflections from reflective surfaces. The shinny surfaces create polarized light and degrades the image. The polarizing filter prevents the polarized light from entering the lens, thus giving the effect of saturating colors. Use of polarizing filters indoors is usually not recommended due to the light loss.

Ken Tanaka · March 28th, 2004, 02:32 PM

Additionally, no, neutral density (ND) filters do not serve the same purpose. ND filters simply reduce all light through the lens. They do not polarize the light.

Grant McClintock · March 30th, 2004, 03:55 PM

I haven't seen the B+W polarizers. Are they actually lighter? The filter factor is the same as for a Tiffen. Grant

Ken Tanaka · March 30th, 2004, 04:46 PM

I have two. Honestly, I can't technically confirm that but they do appear a bit lighter than my Tiffen. However, it's largely a moot point, as you would be using it in bright sunlit settings anyway.

Jeff Donald · March 30th, 2004, 07:26 PM

Are we talking lighter as in weight (B+W is probably heavier they're made with brass mounts) or optical density? The optical density is not an accurate gauge of their effectiveness.

Matt Gettemeier · March 31st, 2004, 06:53 PM

I guess I wouldn't be totally concerned about it, but when I said the B+W polarizers are lighter... I meant less dark. The construction is super solid.

With such a BIG lens 72mm it's a bit of a job to clean a MC filter properly. I use some stuff called Formula MC that I got from www.2filter.com and it works pretty good.

B&H has the best price on polarizers... I coulda' saved close to $20 if I'd have bought mine from them.

The one I'm using now is called an FPRO. It's a B+W multi-coated job and it's significantly less dark then the Tiffen's I've used in the past.

The reason I care about having a lighter polarizer is 'cause I use mine indoors to eliminate glass also. I should post some frame grabs from Shed Aquarium in Chicago. There's a few shots where I had to turn the polarizer while shooting and it goes from a window reflecting some young ladies... to what looks like a huge fish floating in mid-air.

Of course I wouldn't get bent on paying the highest possible price for a polarizer either... they all work and I don't know if I could justify exactly why I like B+W so much... but I do.

March 28th, 2004, 01:48 PM	#17
Jeff Donald Warden Join Date: Mar 2002 Location: Clearwater, FL Posts: 8,287	Polarizers typically reduce the light by 1.5 stops to 2 stops of light. The saturation of colors is a result of reducing reflections from reflective surfaces. The shinny surfaces create polarized light and degrades the image. The polarizing filter prevents the polarized light from entering the lens, thus giving the effect of saturating colors. Use of polarizing filters indoors is usually not recommended due to the light loss. __________________ Jeff Donald Carpe Diem Search DVinfo.net for quick answers \| Where to Buy? From the best in the business: DVinfo.net sponsors

March 28th, 2004, 02:32 PM	#18
Ken Tanaka Retired DV Info Net Almunus Join Date: Dec 2001 Location: Chicago, IL Posts: 6,943	Additionally, no, neutral density (ND) filters do not serve the same purpose. ND filters simply reduce all light through the lens. They do not polarize the light. __________________ Lady X Films: A lady with a boring wardrobe...and a global mission. Hey, you don't have enough stuff! Buy with confidence from our sponsors. Hand-picked as the best in the business...Really! See some of my work one frame at a time: www.KenTanaka.com

March 30th, 2004, 04:46 PM	#20
Ken Tanaka Retired DV Info Net Almunus Join Date: Dec 2001 Location: Chicago, IL Posts: 6,943	I have two. Honestly, I can't technically confirm that but they do appear a bit lighter than my Tiffen. However, it's largely a moot point, as you would be using it in bright sunlit settings anyway. __________________ Lady X Films: A lady with a boring wardrobe...and a global mission. Hey, you don't have enough stuff! Buy with confidence from our sponsors. Hand-picked as the best in the business...Really! See some of my work one frame at a time: www.KenTanaka.com

March 30th, 2004, 07:26 PM	#21
Jeff Donald Warden Join Date: Mar 2002 Location: Clearwater, FL Posts: 8,287	Are we talking lighter as in weight (B+W is probably heavier they're made with brass mounts) or optical density? The optical density is not an accurate gauge of their effectiveness. __________________ Jeff Donald Carpe Diem Search DVinfo.net for quick answers \| Where to Buy? From the best in the business: DVinfo.net sponsors

March 28th, 2004, 11:34 AM	#16
Johann Adler Regular Crew Join Date: Jan 2004 Posts: 40	This polarizer topic is interesting. I remember those from Physics class in college. My professor told me that polarizers mearly pass natural light into one plane. Also, concerning getting a light polarizer. According to the equation for a linear polarizer, the iradiance of light passing through it is always halfed. So this could only be useful in very bright scenes? In practical usage, does a neutral density filter perform a similar function? Can/should they be used together? If no to both questions, then why don't the prosumer cameras include them? Very interesting,

March 30th, 2004, 03:55 PM	#19
Grant McClintock Regular Crew Join Date: Feb 2004 Location: Tulsa, OK, United States Posts: 28	I haven't seen the B+W polarizers. Are they actually lighter? The filter factor is the same as for a Tiffen. Grant

March 31st, 2004, 06:53 PM	#22
Matt Gettemeier Major Player Join Date: May 2003 Location: St. Louis, Missouri Posts: 936	I guess I wouldn't be totally concerned about it, but when I said the B+W polarizers are lighter... I meant less dark. The construction is super solid. With such a BIG lens 72mm it's a bit of a job to clean a MC filter properly. I use some stuff called Formula MC that I got from www.2filter.com and it works pretty good. B&H has the best price on polarizers... I coulda' saved close to $20 if I'd have bought mine from them. The one I'm using now is called an FPRO. It's a B+W multi-coated job and it's significantly less dark then the Tiffen's I've used in the past. The reason I care about having a lighter polarizer is 'cause I use mine indoors to eliminate glass also. I should post some frame grabs from Shed Aquarium in Chicago. There's a few shots where I had to turn the polarizer while shooting and it goes from a window reflecting some young ladies... to what looks like a huge fish floating in mid-air. Of course I wouldn't get bent on paying the highest possible price for a polarizer either... they all work and I don't know if I could justify exactly why I like B+W so much... but I do.