A polarizing filter is a must have for any outdoor photographer. Here’s what it does:
- Increases Contrast
- Reduces Reflections
- Saturates Colour
- Improves washed out skys
- Protect your Lens from damage
It’s always a good idea to attach a protective filter to the lens of your camera so you might as well stick a good polarizer on there to improve your pictures and give you more control.
Here are some downsides to using a polarizing filter:
- Reduces Reflections – Sometimes you might want to keep the reflections
- Can create unnatural looking dark spots in your sky
- It reduces the amount of light entering your lens forcing longer exposures (sometimes a good thing)
The good news is that all of these downsides can be avoided simply with a slight turn of the filter.
You’ve probably seen shots like this one which I took in Yosemite National Park last summer.
Using a polarizing filter enabled the camera to see through the reflections in the water of the Merced River, exposing the rocks below the surface.
I also used the polarizer to bring back the blue of sky which would otherwise have been washed out and mostly white.
Take shots with and without the polarizing effect.
Sometimes it’s nice to have reflections in your image, especially if you’re taking pictures of a lake scene that has mirror like reflections. You can adjust the polarizer to reduce the reflections but it’s always nice to have extra shots of the polarizer fully engaged and also not engaged at all. This gives us many options in post processing.
This shot is a composite of shots that used different polarizer settings, allowing me to blend the layers in Photoshop to only show reflections in the places I wanted and not just what the polarizing filter offered me.
When a Polarizing Filter Causes Problems.
The main issue I have with my polarizer is that is causes dark spots in the sky when set to certain positions. This is caused by the proximity of the dark part of the filter to the actual lens of my camera.
Because I have a 16-35mm wide angle lens the problem is more pronounced. I can easily adjust for this but it’s a problem that I always have to be aware of and I have to shoot extra exposures to compensate, adding more time in post processing.
You can really see this in my Mono Lake Sunset shot.
Polarizers can force longer exposures
Because you are using the polarizing filter to reject some of the light entering the lens you’ll need to adjust your exposure settings to suite. Most of the time this is not a problem and can sometimes enhance a shot that has some movement.
If you were to switch from taking a landscape image to a wildlife image you’re probably going to want to remove that polarizer ASAP, unless of course your wildlife is keeping perfectly still.
How does a Polarizing Filter work?
Rather than try to rehash the technical specs of how a polarizer works it’s magic here is a link to a pretty good Wikipedia article that covers more than you’ll ever need to know on how a polarizer works.
Now that you know the benefits and pitfalls of using a polarizer you can be prepared and get the best out of this really useful technology. The main takeaway from this article is that you should not rely on the polarizer to get all parts of your image right. Use it to fix certain areas of your shot and make multiple exposures with different settings to give you more control back in the lab.