On this image I used a 10 stop B&W neutral density filter. The exposure was F22 at 30 seconds, with minus 3 stops EV. The time was 10 AM on a sunny day.
A lot of photographers know that morning and sunset have what is called sweet light. For those that don’t know about this, it refers to the two times a day when the sun is low on the horizon. As a result the light is warm and soft. The shadows are subtle and not pronounced or harsh. These periods of sweet light come twice a day but don’t last long.
That leaves a lot of daylight where the light is not sweet but rather harsh. The shadows are pronounced and there are specular highlights on the surface of the water, rocks, beach, and foliage. If you have ever looked at on the ocean during the late morning and afternoon and seen small blotches of reflected sunlight on the water that shimmer, you have seen specular highlights.
Fortunately there are tools available that photographers can use to manage and modify the light. Common techniques include diffusion, subtraction, reflection. These tools are made from a variety of materials and as their names suggest soften the light falling on a subject. Opaque materials diffuse the light, black material subtracts light, and reflectors add light. Using strobes is another way to control light but these are better suited to portraiture, and product photography.
Another way to control the light is to use filters. To reduce harsh light polarizing filters are used. These remove glare and add a sense of clarity to the image. Graduated filters are used to match uneven levels of light. Lets say for example you want to photograph a beach scene. The back ground is very bright say F16 and the foreground is not as bright say F8. You could use a 2 stop graduated filter over the lens. The dark part is for the background and the lighter portion for the foreground. Now when you meter the scene the foreground and background are the same or within a stop.
Neutral density filters are used to control the light entering the lens and CCD chip. These filters come in different increments. There are 1-stop, 3 stop, 6-stop, and 10 stop filters. These filters can be used to control light. As an example lets say your at the beach and you want to photograph the incoming tide rushing in and out and in the process the rocks are submerged, exposed, or have small rivers of water cascading down the sides. when you use a neutral density filter you can modify the exposure. Lets say the light meter in your camera measures the beach scene at F22 at 1/125th of a second, and you want to slow the shutter down enough to soften the scene. In this case you would need a shutter speed of 1/15th of a second. This is 3 stops lower than the light meter reading. When you crate the image at f22 and 1/15th you will see that water is not hard. You won’t see individual droplets popping out of the wave, or bouncing off the rocks. What you will see is a swirly flow of water that is smooth. Now lets say you select a 6 stop filter. The light meter reading has not changed and is F-22 at 1/125th of a second. After putting on the filter the exposure is now F-22, at a 1/2 second. Using a 10 stop filter you would be at F-8 and have a shutter speed of 8 seconds. With the shutter open this long you will turn the water into a smooth, almost erie looking white.
There are many brands of neutral density filter. The best are Lee, B&W, and Schnieder. None are cheap. But, you do get what you pay for. I have the B&W filter and am planning to purchase the Lee system as soon as possible. I am very happy with the quality of images the B&W filter makes but since the filter scores on to the lens you can’t see through the view finder to compose the image. So I have to compose and the screw on the filter. Then I have to make a few exposures and make some fine tuning. The lee system uses an adapter ring on the from of the lens so the filter can easily slide in place or be pulled out to recompose. This is much easier but their is a cost involved. The lee system kit with a three kinds of neutral density filter and adapter ring can cost up to $470. The B&W filter I bought was $200.
Setting the exposure when using these filters is fun and involves trial and error. I like the look and feel of the ocean when using shutter speed ranging from 1/15th of a second to 30 seconds and even longer. Using the histogram feature on the camera body will help you tweak the exposures. You want a nice bell curve with information spreading all the way to the left and right.
If you have to make a choice to under expose or over expose keep in mind there is more information in an over exposed file than a underexposed file. When editing images you can open photoshop and drag the sliders to fix the exposure value. You will be surprised at the information that is there.
Using the cameras exposure compensation control is another way you can tweak the exposure. Lets say your shooting f-22 at 30 seconds with a 10 – strop filter and you feel the image is really over exposed. You can set the exposure compensation plus or minus five f-stops. So this will let you compensate and override the cameras exposure. This added control is priceless.
While the majority of photographers use wide angle lenses when using filters for landscape photography you can also use a telephoto lens or standard portrait lens. In the image below I used the 85 mm 1.4 Nikon portrait lens. The subject was the exposed reef. The location is Sugar Beach on Maui. I used F-22 and 30 seconds on this exposure.
When I look at this image I thought I was looking at the top of a group of mountains that were so tall that the clouds covered them up and all that is exposed are the summits. But actually this is the top of a coral reef that is exposed during low tide. To create this image I had to lay down on the sand and make my tripod go as low as it would go. I timed the images such that a wave kind of lapped over the reef top. This created the mist and erie feeling.
I have been a professional photographer for over 2 decades. Unitl a month or two ago I did not use neutral density filters because I was a purist and thought if I could not do it in camera I did not want to try. What can I say but that n old dog can learn new tricks. I am creating some beautiful images, testing my creativity and artistry, and most of all I am having fun.
Using filters allows each photographer to explore their creativity.