Polarizers 101: How an Inexpensive Filter Can Change Your Photography
Arguably the most valuable filter in a photographer’s arsenal is the Circular Polarizer. A simple, dark filter that rotates on the lens has the ability to darken skies, control reflections and reduce your aperture for diminished depth of field and greater bokeh.
Get Reflections Under Control
A very useful facet of a Polarizer is its ability to manipulate reflections. If you find yourself in a situation where you have to shoot through a reflection, a Polarizer will come in very handy. To demonstrate this, you’ll see that the first shot was made without the polarizing effect.
Simply twisting the filter to bend the reflected light results in the second picture. Suddenly, the rocks below the surface are revealed. These pictures were taken from the exact same angle only a moment apart, but the effect is completely altered.
Another thing a polarizer can do is darken the sky and make clouds pop. For maximum polarizing effect on skies, point the camera at a 90-degree angle from the sun. You won’t see much of a polarizing effect if you point it towards the sun or in the opposite direction.
Reduce The Light
Finally, a Polarizer can be used to diminish the amount of light reaching the sensor. This allows you to open up your f/stop, diminishing depth-of-field so backgrounds go more out of focus. Polarizers require a 2-stop compensation. This is the same effect as an ND.6 Neutral Density Filter, which cuts the light moving through the lens but does not polarize the light.
Most SLR cameras meter the light through the lens, so you will not need to compensate your exposure manually; the camera will adjust the exposure for you. When shooting in bright light, those 2-stops of exposure can make a big difference in how your picture turns out.
When purchasing a circular polarizer, buy one that fits your lens with the largest front diameter. To adapt to your other lenses, you can easily purchase inexpensive adapter rings to make the one filter fit all of your lenses. You can find polarizers at any camera store, Amazon.com and used ones at KEH.com.
While photo editing can help to darken skies and even blur backgrounds, there is no substitute for a Polarizer when it comes to manipulating reflections. This one simple filter is an indispensable tool in every photographer’s bag.
Responses and Conversations
Nice article. To the point. Short and sweeet. An easy read.
Comment by Les Stockton on August 6th, 2008 at 7:10 am
I think you pushed me a little bit closer to getting a polarizing filter for my 10-20mm lens. I have been wanting one for a while now, but I haven’t spent the time and energy required to secure the funding from my wife!
Comment by John Brainard on August 6th, 2008 at 9:18 am
I hear you, John. That’s probably a pricey filter with such a large front element to the 10-20mm lens. But think of what cool landscapes you could do with the pola on that lens!!
Comment by Stephanie Simpson on August 6th, 2008 at 9:20 am
Yeah… The Hoya HMC isn’t so bad at $78. The Hoya DMC PRO1 is a bit more than I was hoping to spend at $194 (prices according to Amazon).
Have you any idea if a newbie like myself would be able to tell the difference between the two filters?
Comment by John Brainard on August 6th, 2008 at 10:29 am
I’d be surprised if you could see any difference. It’s the kind of item you really don’t have to spend a lot of money on for the fancy brand, unlike some lenses, for instance. I bought my 77mm circular Polarizer used at KEH.com for only $40. There were no scratches or dings when it arrived and you can see it works great.
Comment by Stephanie Simpson on August 6th, 2008 at 1:10 pm
Take a look at ebay for filters. With the switch to digigal, people are unloading filters because they don’t think they need them anymore. A few years ago, I picked up my 77mm Hoya Super Multi Coated Extra Thin filter (or something like that) for $40. It was selling new for $175. I love ebay (as a buyer).
Comment by John Koontz on August 7th, 2008 at 3:05 pm
@John Brainard: Do you own a Sigma 10-20mm by any chance? I bought one this summer before a recent trip to China - love it! I ended up purchasing a B+W slim polarizer - it was expensive, and I probably wouldn’t have noticed the difference had I chosen a cheaper filter - but it seems like a good filter is not something you want to go cheap on, and with a step-up ring, I can also use it on my 70-200mm L.
Stephanie - what a dramatic example to demonstrate the power of a polarizer - that can never be achieved in Photoshop!
Comment by Chris Oquist on September 12th, 2008 at 9:39 pm
Thanks, Chris! I have been thinking about the Sigma 10-20mm as well. I drooled over it in Samy’s Camera about a month ago, but had to walk away. I was in a very spendy mood that day and if I had let myself go, that lens would only have been the tip of the iceberg!
Comment by Stephanie Simpson on September 13th, 2008 at 11:53 am