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Quick Tip: An Introduction to Polarizing Filters

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Over the next month we are going to take in depth look at different photography filters. We will find out what each one does and then how to use them. We start with a common filter used by beginners - the polarizing filter. We'll take a look at what polarizing filters do, how they help your photography, and where you can get one from!


What Does a Polarizing Filter Do?

Put simply, polarizing filters remove reflections from non-metallic surfaces. So how does this help us as photographers?

To begin with, on a nice sunny day it allows us to darken the sky by completely removing the reflection of light off the tiny water droplets present in the atmosphere.

If you are shooting water, such as a lake, a polarizing filter will remove the reflection and give the water a more transparent look. The only problem is the angle you shoot at. If shooting above the water it will be appear completely transparent whereas shooting from a low side angle will not give the same effect. This might be perfect for an angler with a photography hobby or visa verse.

Polarizing filters also absorb light - anything up to a whole 1-2 stops (depending on make and brand). This means that you have to decrease your shutter speed in order to capture the shot your after. If you are shooting mid-evening you will almost certainly need a tripod. This feature can be a positive if you like shooting long exposure photography or a negative effect if you don't.

Last but not least is the fact a polarizing filter is a colour enhancer. The polarizer brings out the colour of the natural world and improves your photos. The reason this happens is because the polarizing filter removes reflections from all the objects around and it darkens the shadows. It is one of the only filters which creates a result that you couldn't really achieve in Photoshop post-processing.

polarizing filters

Image courtesy of Your own, personal, Jesus


What Types Are There?

Polarizing filters come in both linear and circular varieties. I will not go into the physics, but overall the effect is the same in both of them. The one you choose is down to your camera.

A circular polarizer is needed when dealing with auto-focus or spot-metering systems. Almost all modern SLR cameras will need a circular Polarizer, and some SLR film cameras will as well. If you are unsure about your camera if should state in the manual. Linear polarizers on the other hand will often be suitable for older manual SLR film cameras.

You will then have the choice to buy a circle or square filter set. Circle filters you simply screw the filter onto the end of your lens and then you are good to go. A disadvantage is that these will only fit the lens you have - for example a kit lens is around 58mm, whereas a telephoto might be 64mm. You would need to buy two filters or a huge number of step down rings!

Square filers are larger and fit into a holder. If you need another lens size you simply buy a new adapter ring which attaches the holder to the camera. It's really easy and allows you to easily stack more filters on top of each other. If you would like to read more, take a look at the following article..

When using a polarizing filter, you will need to rotate them in order to get the effect you require so look out for these common features:

  • Look for a circular filter with a small screw-in arm in order to help rotate the filter. These are handy if you find small components difficult to work with.
  • When using wide angles, filters with thick casing can cause a vignette around an image. This is also true for the filter holders of Linear filters.

The image below shows a filter holder on the left holding a ND grad and on the right a Polarizer. A polarizer needs to be rotated and will be always be circle.

polarizing filters

Image courtesy of scalespeeder


Polarizer Brands and Pricing

Like all photography gear, you get what you pay for. Polarizing filters can be picked up for near $10, but I personally wouldn't trust them anywhere near my camera. Here is a look at a few brands I have dealt with and would recommend to anyone.

  • Hoya produce some amazing filters, and have recently created a Polarizer with multi coat protection. This gives your filters greater protection, and they will withstand more damage. They are a good price for the quality and come in around $50-$80 depending on the thread size.
  • LEE filters are aimed at the professional and are one of the best quality filters on the market. A LEE Polarizer would set you back around $200-300 per 100mm filter.
  • Cokin are the brand I recommend to amateurs and those on a tight budget. Cokin produce cheap, high quality filters which fit their special P holder which can be put onto any lens (with the right adaptor). The price for a square polarizing filter is approximately $50-80.

Other good brands include B +W, Hama, Sigma and Cromatek.

polarizing filters

Image courtesy of christian.senger


Tips When Using a Polarizing Filter

Here are a few tips to think about when using polarizing filters:

  • Using a wide angle lens is not advised when using a polarizer because the image becomes unevenly polarized (28mm is often stated as the max)
  • You will want to be at a 90 degree angle to the sun to achieve maximum polarization. Shooting with the sun behind you is more likely to lead to a poor result.
  • If you use the polarizer on top of another filter, you might be prone to a noticable vignette.
  • Don't shoot through glass, or thick plastic/perspex, as you might end up get random colour splats like in the image below.

polarizing filters

Image courtesy of Jezkerwin


Conclusion

I hope that you've found this article to be a useful introduction to this type of filter. Polarizers are really good fun to play around with and, if you wish to find out more, I'd recommend taking a look at the articles below:

polarizing filters

Image courtesy of globalindex

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