Cutting the Glare and Other Benefits – Polarizing

By Robert Jordan, University of Mississippi

Back when I shot film I carried many optical filters to correct and enhance light. I had one each of: red, yellow, sepia, cc30r, 81A, two square gradient filters and three polarizing filters. Digital photography, with the ability to change white balance with the flick of a dial, has made all of my color correction and contrast enhancing filters obsolete. Bracketing exposures and postproduction techniques have made my square gradient filters equally redundant. But I still carry one circular polarizing filter (CPF) for every lens in my bag so I can mount a CPF to each lens and do not have to swap one filter back and forth when I change lenses.

Polarizing the light passing through the lens reduces reflections from non-metallic surfaces, reduces glare and intensifies color in a way not possible in post-production. Under the right conditions, a polarizer can intensify a blue sky, punch up colors and help reduce shiny highlights, even on skin. The only catch is that all this magic comes at a cost of about 1.5-stops of light for a standard CPF.

There are many types of polarizing filters available, linear or circular (use circular for auto focus cameras), standard or low light (-1.5 stop standard, -1 stop for low light), neutral or color enhancing, standard or slim mount (slim mount is less likely to vignette). For the purposes of this article I’m going to restrict my discussion to neutral color, circular polarizing filters (CPF).

Years ago there was a wide range of the optical and build quality between the filter brands. I have several older CPFs from the same mid-range manufacturer that are supposed to be identical, but they actually vary slightly in light transmission and color neutrality. This is why I have tried to stick with the premium brands over the years.

How do current CPF filters fare? Calumet Photo supplied three 77mm circular polarizing filters from three different manufacturers at very different price points for side by side testing and the results of my testing have made me rethink some things.

The filters supplied for testing are: Calumet Traditional Uncoated ($35.99) which is 6mm thick with threads on the front for stacking an additional filter. Tiffen’s standard filter ($68.99) is quite thin for a ‘regular’ filter at 5mm thick with threads on the front for stacking an additional filter. B+W’s Slim filter ($149.99) as the name implies, it is very thin at 4mm thick and lacks front threads.

I prefer to shoot with a CPF and the dedicated lens hood on all my lenses, so I refuse to use a CPF if I can’t attach the filter to my lens and then attach the lens hood. Some CPF filters are a bit too large in circumference to mount some hoods, but all three of the tested filters fit fine with the hoods on my Nikkor 17-35mm, 24-70mm, and 70-200mm lenses.

I tested the density characteristics of all three filters by holding each filter over the light dome on a Sekonic L-3088 digital light meter in a dark studio with a halogen light source directly over the filter and dome. I found all three CPFs to be identical within the limits of the meter’s accuracy of 1/10-stop.

Looking at the filters side by side, they all look to be the exact same shade of gray, unlike my personal collection of CPF filters. Next, I attached a Macbeth Color Checker target to a light stand and photographed it with a tripod-mounted Nikon D3s using two different Nikkor lenses under both daylight (camera set to daylight WB) and halogen lighting (camera set to incandescent WB) conditions. I shot a complete series of photos with no filter and with each of the tested filters perpendicular to and at angles to the target and light source. I opened each of the jpg files in CS4 and checked 101x101-pixel averaged samples of the gray test targets on the Color Checker photos. I could only detect a few points difference in the RGB channels between any of the files shot under each lighting condition.

Nor was I was able to detect any difference in performance between any of the three CPFs in photographing a clear, blue sky to the East and West at midday or in photos of a glossy black enamel appliance trim test panel shot at several angles relative to the sun. In all of my testing, I was unable to detect any meaningful differences in density, effectiveness or color rendition.

So which brand would I buy/recommend? I can’t say until I perform my polarizer
Modification on all three.

All polarizing filters have a threaded ring that mounts to the lens and a ring that must be rotated to align the polarizing material for maximum effect. All CPFs I have encountered use a dab of lubricant between the two parts to smooth and dampen the rotation. There is a lot of surface area that is in contact between the two parts of the filter and very little filter to grab onto to turn, making most filters overly difficult to rotate for my taste. Over time, the lube attracts dust, dries out and gets even stiffer. The resistance the lube adds makes it nearly impossible to reach inside a lens hood and rotate the CPF. Even worse is that in cold weather the lube thickens making the filter nearly impossible to rotate, especially with gloves.

I prefer to remove all of the lube and use the filter dry. Once the grease is removed, it’s easy to reach a single fingertip through the lens hood and turn the filter while looking through the lens. A solvent is needed to remove the lube from the CPF, automotive engine degreaser works great. Spray a shot or two of engine degreaser between the filter’s rings and rotate the filter for a minute or so until it really loosens up. Rinse the CPF in warm water. Next, squirt some liquid dish washing soap between the filter’s rings and rotate some more, this will remove all of the degreaser. Clean the filter surface front and back with the soap. Rinse. If the CPF feels gritty when you turn it, repeat the steps. Pat dry with a soft towel and let the CPF dry overnight.

I degreased all three tested filters. The B+W became much easier to rotate and the Tiffen will spin like a roulette wheel and is very easy to rotate with a fingertip through a lens hood.

The Calumet was easier to rotate, but would occasionally bind. I cleaned it again, but it just seemed ‘unhappy’ without lube. So I added a miniscule drop of very light weight sewing machine oil with a toothpick between the two rings and rotated it to distribute the oil. I cleaned up the area where I added the oil with a paper towel. It’s easier to turn than when I removed it from the packaging, so I still consider it to be a successful modification.

Which brand you buy really depends on your priorities. The Calumet is an amazing bargain, delivering top-notch performance for a fraction of the cost. The Tiffen is a great balance of thin-ish profile with front threads and it spins like a top after modding. The B+W is the go-to filter for wide lenses with a very thin 4mm profile, thinner than many UV filters.

Any of these filters will improve your images in the studio and in the field. I would not consider attending this year’s Symposium in Utah without CPFs for all of my lenses!

Robert Jordan is the Director of Brand Photography Services at The University of Mississippi, and can be reached at 

rjordan@olemiss.edu