Pro Guide: Polarizers

Posted by on Jan 6, 2017 in How To, Tech | No Comments

What is the #1 easiest way to instantly improve your photos and video? Polarizing filters. These are indispensable tools that should be in all shooter’s camera bag, particularly if shooting landscape/scenery/outdoor subjects.

This will be a quick guide to their various uses, benefits and pitfalls. My goal is to equip you with practical knowledge you can bring into the field and instantly improve your work without getting too scientific or technical. Let’s get to it.

What Is A Polarizing Filter?

Simply put, a polarizer is a piece of special coated glass that you screw, or place, in front of your camera lens. It offers a variety of ways to control light coming into your lens, all of which [can] make your image look better.

Polarizers remove harsh reflections in your shot, increase contrast and boost colour saturation/vibrancy (particularly with water and greenery). In the right conditions, polarizers can have extremely dramatic and positive effects on your photos.

How Do They Work?

For most standard lenses that have a filter thread on the front, you can get a ‘circular polarizing filter’. This is a filter that you screw onto your lens and rotate either clockwise or counter-clockwise to get different amounts of polarization.

Polarizing filters work by blocking certain light waves from entering the lens. Rotating a polarizer allows certain types of light waves to pass through, while blocking other ranges of light waves. Thus, you could turn a sky from light blue to very dark blue or increase/decrease reflections by simply rotating the filter.

The easiest way is to visually see it for yourself. Check the images below:

 

Shooting outdoors is all about controlling the light around us— polarizers offer one more toolkit in your arsenal to do so.

How To Use Them Effectively

The caveat to these magical devices, is that they are the most effective when positioned 90 degrees to the sun… and have little to no effect when shooting directly into or away from the sun.

You will have to be thoughtful about your shooting position, angle and the time of day. Luckily, they can be rotated on your lens to adjust this angle (relative to the sun), allowing you to find that sweet spot for maximum polarization.

When you do nail that sweet spot, you’ll know right away. Images appear more saturated, water becomes crystal clear (often times allowing you to see the bottom), your skies will be brighter and bluer, and plants greener and more lively. Interestingly, you will also be able to see through tinted windows (i.e.: in cars).

The image below was taken from my DJI Phantom 3 Pro using a polarizer. Notice there is no ugly white reflections on the water— in fact you can actually see the bottom of the lake. In this particular shot, the polarizer made the shot.

Regarding saturation, it’s important to know that it isn’t always increased uniformly. This all depends on whether a particular object is at an optimal angle to the sun, and whether this object is highly reflective. In general, more reflective objects will see a greater increase in saturation when using a polarizer. Clear sunny days are also much more heavily influenced by polarizers than overcast or rainy days.

You can obtain maximum polarization when the sun is roughly 37 degrees from the horizon. If the sun is directly overhead or very close to the horizon, the effects of the polarizer will vary. In some cases you might not even see any polarization effect no matter how much you rotate the filter.

Lastly, polarizers cut about 1-2 stops of light coming into to your camera (they make the image darker). Depending on your situation, this could be a good or bad thing. Regardless, it’s worth noting.

Pitfalls

  • Improper Use: Polarizers when used improperly can cause unnatural looking photos/video. The most frequent case, is a sky with an uneven gradient. When dialling in your shot, be mindful of your angle to the sun to alleviate this. Here is an example I took in Malta:
When I took this shot, I was more focused on the water and its clarity— no ugly white reflections on the surface, the colours are vivid, and you can see the sea floor… however, the sky looks slightly unnatural. I should have either further adjusted the polarizer, or repositioned the boat to rectify this shot.
  • Skin Tones: Polarizers can also tend to make people’s skin appear more ‘plastic.’ This isn’t always a negative thing, but when shooting interviews or taking portraits be mindful of the naturalness of your subject’s skin tone.
  • Wide Angles: Polarizers are generally not recommended for super wide angle shots for the reason above (24mm and below). These shots are often so wide that you will not be able to get realistic and uniform results from across your image.
  • Price: Polarizers are can be quite pricy as they are one of the only lens filters which cannot be replicated using digital photo editing. I own a B+W 58mm Kaesemann Circular Polarizer MRC Filter for my Panasonic GH4 which cost me about $100 at time of purchase. I really like this filter and it has served me well more times than I can count all over the world. Quick tip: If your lens is (for example) 58mm, you will need a 58mm polarizer. Make sure you double check this before you drop the dough.
  • Panoramas: Another potential pitfall/consideration is they aren’t good at panoramas or stitching photos. As the angle of the sun is so imperative to their operation and panos require lots of camera movement, you’re going to get some wonky results. Here is an extreme example:

Good luck fixing that in post.

Final Thoughts

In the right situations and with a little practice, polarizers can have a dramatic and positive effect on the quality of your image. In my opinion this is an essential piece of kit; I take mine everywhere I go. Take your photography or video to the next level, get a polarizer!

Thanks for reading and happy shooting!

– Chris

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