One of the most useful filters to consider purchasing is a polarizing filter. A polarizing filter is one of the most essential tools in a landscape photographer’s bag. No other filter will do more to add ‘pop’ to your images. Most landscape photographers buy Polarizers to instantly improve their pictures and add vividness and contrast to them. Getting better image quality by using a circular polarizer filter is so easy. A polarizing filter can actually make the sky look more dramatic, once you learn how to use it properly.
Basically, a polarizer can reduce reflections from objects such as water and glass (i.e. non metallic surfaces) and can be used to darken the sky and bring out the clouds, making the scene look much more vivid. It is also used to reduce haze in the image.
A circular polarizer is very easy to use. When you attach it on the front of your lens, you need to rotate it clockwise or counter-clockwise to get a different amount 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 front part of a circular polarizer filter rotates continuously in either direction, allowing you to dial in just the right amount of effect.
Do remember, time of the day plays a big role in the amount of polarization you can get from a polarizing filter. You can obtain maximum polarization when the sun is at about 37 degrees from the horizon, if the sun is directly overhead or very close to the horizon, the effect of the polarizer will vary and some times you will not even see any polarization effect even you fully rotate the filter. The effect of polarization is depend on the angle of the sun. The maximum effect of polarization is achieved when the lens is pointed 90 degrees from the sun in any direction.
A simple trick to find polarizing zone for darkening sky only, where circular polarizing filter works best is, point your either hand at the sun, make 90 degree angle with other hand and rotate your other hand from front to back direction in 90 degree from sun. This is the zone where polarizer filter works best.
If the sun is in front of you, or behind you close to the horizon, you did not see the effect of polarization on the sky at all. The polarizer filter can still used to reduce haze and reflections on non metallic surface, but it will not do anything to the sky. Also, you have to be very careful when using a polarizer with super wide-angle lenses i.e. 24mm and below, because the sky might not get darkened equally, resulting in a bad-looking half blue-half lite blue or gray sky.
I always check my rear LCD after shooting with a circular polarizer, making sure that the sky looks same from left to right.
Circular polarizer filters are also work as weak Neutral Density filter. Expect a light loss of 1 to 2 stops when using the circular polarizer filter. This is good news for those situations when you want a longer exposure such as to blur moving water, but bad news if you need a faster shutter speed or aperture.
When not to use a circular polarizer filter?
This is the most important question. This is not a filter that most people leave on a lens all the time – Circular Polarizer filters are not used in all photography situations. As just discussed, there is less light reaching the sensor, so I don’t use a Circular Polarizer filter when shooting action and/or in low light. I generally do not use Circular Polarizer filters for portrait photography. But, the with or without filter choice is always yours. As you gain experience with your Circular Polarizer filter, you will learn when it does and does not make sense for you personally to use it.
Cheap, low quality filters.
I do not consider a cheap, low quality filter to be acceptable for most circumstances. Many of these exist, do not buy them. They will degrade the quality of your pictures with ghosting, flare and loss of contrast being the primary issues. Image sharpness can also be affected.
If I photographing something that is important to me. I’m not going to sacrifice my image quality by putting bad glass in front of my lens and neither should you. Get a quality filter.
A circular polarizer is a very helpful tool in a photographer’s bag. I personally use the HOYA filter, because of its high quality optics, but you can use other brands such as – excellent quality – B+W, Singh-Ray, or if budget matters go for Tiffen as well.
Just make sure that you are buying the right size for your lens filter holder. For example, if your lens filter thread is 77mm, make sure to buy a 77mm circular polarizer. If you have multiple lenses of different sizes, I recommend buying one 77mm filter in addition to cheaper step-up rings.
While polarizing filters are clearly very useful, their disadvantages are that:
- They can make the exposure require 1-2 stops more light than normal.
- They are one of the most expensive types of filters.
- They require the camera to be pointed at a right angle to the sun for maximal effect.
- They can take longer to compose with since they need to be rotated.
- They can be difficult to visualize when using the camera’s viewfinder.
- They can potentially reduce image quality if the filter isn’t kept perfectly clean.
- They cannot be used with Panoramic or wide-angle shots.