Ruth Renner took a photo of her cow’s eye and couldn’t get the detail that she wanted because the eye was acting like a mirror and reflecting an image of the surrounding paddock. Also, the black cow looked partly white due to light reflecting off her hairs. A polarizing filter is the widget that will reduce these reflections: if you’ve ever had polarized sunglasses you’ll have a good idea of what a polarizing filter does.
Polarizing filters not only reduce obvious reflections, they also reduce the reflections that you’re not aware of. Things like foliage reflect light and desaturate (water down) the colours, so a polarizer will give a pleasing result that shows the “real” colours of the foliage. They work best in bright, high-contrast light (i.e. when the shadows are really dark), and are generally best avoided in low contrast situations such as a heavily overcast day.
When your polarizing filter is on your camera you rotate it until you get the desired effect: generally the full effect will look awful, and somewhere around half way between minimum and maximim effect is about right. It’s all a matter of taste and experimentation. Polarizing filters are good for the following situations (this is not an exhaustive list):
- taking photos at the beach, by a lake, or in the snow
- taking photos of water: you can stop the water looking like a sheet of white and see some details under the water
- taking close up photos of cows, as we all do
- taking photos of foliage
- taking photos of people wearing shiny nylon jackets: with a polarizer you can see the true colour and greatly reduce distracting reflections
- photographing blue skies, with or without clouds. Clouds look superb when a polarizing filter is used
- taking photos of things inside glass cases (without flash)
- taking photos of people who are outdoors
- generally if the sun is visible or it’s a bright overcast day your photos will benefit from some degree of polarization. Just experiment with different lighting conditions and different rotations of the filter, but avoid the temptation to leave the filter on all the time.
How do you attach a polarizing filter to your camera?
If you’ve got a SLR just buy one of the right size and screw it on to the end of your lens.
I know that Ruth’s camera is a Canon compact zoom that will take an adapter tube (pictured). This is literally a tube: you attach one end to the camera and the polarizing filter screws into the other end. In this case it’s a good idea to get a lens cap (with lanyard/retaining cord) to protect the filter. The adapter tube will also protect the delicate zoom mechanism. The Canon adapter tube is made of flimsy plastic, but metal aftermarket versions are available.
Only a minority of cameras are made to take adapter tubes, so what do you do if yours isn’t one of them? You can just hold the filter in front of the lens, but in my experience this is very awkward, you’re likely to have blurred photos as a result of camera shake, and you’re likely to drop an expensive filter. The Cokin Filterfast might be the way to go for you: one advantage of this system is it will fit a wide range of cameras, so you can keep it when you get a new camera or share it with family members.
One thing I have done when I don’t have a polarizing filter with me is hold my high quality polarized sunglasses in front of the camera lens. I don’t recommend this because it’s awkward, camera shake is likely, sunglasses usually aren’t very clean, and it’s not as effective as using a proper polarizing filter. However, if done with care it does improve the photo and that’s what matters.
A polarizing filter is a simple device, and with a bit of practise you can use one to greatly improve your photos. I highly recommend getting one.
Click here to view some of my photos taken at the beach on a cloudless day using a polarizing filter. Without a polarizing filter the colours would have looked desaturated (washed out) due to all the reflections from sand, water and so. With the polarizing filter the colours are saturated and natural; the effect is most noticeable when you look at the sea, which has a nice colour instead of looking pale or like a sheet of white. Photos 1 and 2 show how a polarizing filter allows you to see what’s under the surface of the rock pool, while in photos 3-5 the rock pools look more like they would without a polarizing filter.
Experiment and enjoy – with a digital camera your only cost is time.
For cheap-but-decent polarizing filters I recommend John Thomson Photography. He also supplies lens adapter tubes.