Tuesday, January 3, 2012

Circular Polarizer: Miracle Maker

Circular polarizers are a very interesting piece of equipment and usually overlooked by beginners who only buy UV filters as per the sales person's advice. I like to say that the polarizers are magic makers, the very first time you use one, you will be astonished with what it can do. Hit the jump to learn more.


The polarizer filter idea is the same as your sun glasses, I don't want to get into scientific details about light waves, polarization and stuff, but if you're interested, you'll find a good explanation here. Suffice to say, a polarizing filter cancels a part of the light reflected from any object, be it the sky, a car's windshield or the water's surface.


So how can this be of benefit for you? I'll give you a small exercise, go outside in the morning and try shooting your car from outside and see the car's interior through the glass, mostly (depending on your angle) you'll find that the glass reflects the sky and the surroundings. Check this example:

Now here's the same picture with the circular polarizer:

Just like magic, but the sharp reader will notice that the side windows have become reflective in the second picture, you can't have everything when there are different angles from which the light is reflected. But if I had to have them all clear, I would use a tripod, take two shots and use photoshop to merge the parts I needed.

Polarizers are generally useful in eliminating reflections like the example above, more examples would be shooting wrist watches, shooting fish through tanks, shooting through the surface of the water, etc...

They can also be used to get better contrasting skies and miraculously vibrant images, this works better when you're shooting 90 degrees to the sun (i.e. the sun is either to your left or your right), and since the polarizing effect depends on the angle of reflection, you'll usually find that the sky color doesn't become even across the picture. The picture below is a standard picture shot without the polarizer.

And here's the same picture with the polarizing filter:

Unbelievable! So how do one use a polarizer? See the picture at the top of the post? This is how it looks like, you thread it to your lens like any other filter and you have a part at the front that rotates, and you keep rotating the filter while looking through the viewfinder until you get the look you want. It will also be very good if your lens' front element doesn't rotate with focusing since this will change the filter's rotation each time the camera changes focus.

They always tell you to buy the best brands in filters since they have coatings that minimizes reflections and will not degrade the picture in terms of sharpness, however, polarizers are very expensive especially if you have a large diameter thread, and different lenses with different thread sizes. I myself went for a not-so-expensive 72mm (larget lens thread size I own) Chinese brand since I don't use it a lot, and I didn't find it cost me pixel sharpness at all, and for my remaining lenses I bought some cheap Bower step-down adapters like the one below.




  1. I have a 77mm one mounted almost constantly on my Canon 10-22...a must have !

  2. Hi! Just wanted to clarify for the sake of those those new to circular polarizers (not veterans like you my friend): a cpl is generally not useful indoors (except to avoid reflections) so i wouldnt literally leave a cpl on the lens all the time - it cuts ambient light by a stop or so. :)

    Best regards,

  3. And if you see someone using (like a mad men) a Canon 10-22 indoors...then you can probably teach him a lot of things ! So a 10-22 + a cpl indoors is not even an option haha :D

  4. I have a 77mm one mounted almost constantly on my Canon 10-22...a must have !

    Do you shot primarily or only outside? You presumably wouldn't use a CPL inside, unless I'm missing something.

  5. Using a CPL indoors doesn't make sense to me, unless you're shooting through glass like a wrist watch, or a fish tank.
    Even in full daylight, sometimes I had to increase the ISO to compensate for the light loss caused by the CPL.

  6. Actually the Canon 10-22mm with a good bounce flash (I use the 430EX II on my 60D), works very well indoors. Allows me to get more of the action of my twins. With my 35mm f/2.0 I can get more pleasant photos, but at the expense of some scene being left out (due to the tighter crop). Personally I find the 10-22mm far more useful indoors than the cheaper Canon zooms. The 18-135mm kit that came with my 60D is virtually worthless indoors. Not fast enough to take anything useful and the image quality seems to fall behind that of the 10-22mm and my old 35mm f/2.


  7. Thank you for your insights, but I wonder what the benefit of the CPL indoors? Can you show us indoor photos with and without the CPL?


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