77mm Circular Polarizers - Bowers versus Tiffen
Prepared 2004-12-31 by Bill Claff

Santa brought two 77mm circular polarizers so I had to decide which would go back to his workshop.
The two are the Bowers (also known as Crystal Optics) and a Tiffen wide angle.

I took test shots with both on my 12-24mm f/4G ED-IF AF-S DX Zoom-Nikkor.
Here are thumbnails of the shots:

The rows are 12mm and 24mm.
The columns are no polarizer, Bowers low, Bowers high, Tiffen Low, and Tiffen high. Where "low" is minimum light transmitted and "high" is maximum light transmitted.
Note there is light fall-off but no vignetting even though the Bowers is not "wide angle" or "slim".

Here are the numeric results:

	Percentage Transmitted
	Full				Center
	Bowers		Tiffen		Bowers		Tiffen
	Low	High	Low	High	Low	High	Low	High
12mm	0.54%	72%	0.33%	58%	0.23%	76%	0.04%	61%
24mm	0.14%	51%	0.14%	50%	0.09%	52%	0.10%	51%
range	0.40%	22%	0.20%	8%	0.15%	24%	0.06%	10%

The "full" results are on the entire image while the "center" are on a small circle at the center of the image.

The Tiffen was far more consistent, about 2 1/2 to 3 times narrower range, between 12mm and 24mm (see "range" row).
I chose the Tiffen on this basis as well as the fact that I saw flare with the Bowers at 24mm (see row 2 column 2 in the test thumbnails).