DO YOU NEED TO CUT BACK THE LIGHT – SOMETIMES YOU DO FOR REALLY DRAMATIC IMAGES – THINK ABOUT ADDING A VARIABLE ND FILTER TO YOUR KIT.
• Neutral Density filters evenly reduce the amount of light passing thru the lens without effecting color. • Ideal for reducing bright light in large aperture situations when a narrow depth is field is needed. • Allows for slower shutter speeds when blurring or showing of movement is desired. • Allows balancing of exposure to highlight a key subject. • Lets you use higher iso in bright light. You can buy ND filters in many different strengths and and sizes.
While it would be nice to own all of these, the best solution is to get a variable ND filter that is made by several companies. It was surprising to learn that the more expensive brands under performed, or equaled compared to the less expensive brands like the Tiffen Variable ND filter.
After reading a great many reviews and using several different types of variable ND filters, the Tiffen seems to be the best bang for the buck.
Keep in mind that other brands such as Hoya, B+W, Helopan, Singh Ray, Lightcraft and Fader are all excellent but the Tiffen comes in at a better price range and reviewers felt that the lower price did not mean lower quality.
It is important to purchase what is the largest filter size in your lens kit, or what you may be planning on adding to your kit. You want to buy the Variable ND filter that matches that size and then get step up rings for the smaller filter sizes of your lenses. That saves a lot of money. Also by using a variable ND you are saving money by only having to buy one filter. So let’s say that the largest filter you need generally is 77mm. So you would now buy as an example a 77mm down to 52mm or 62mm or 58mm and so on. Buy the B+W rings as they seem to be easiest on and off your lens. Never stack filters. If you have protective filters on your lenses, remove then first and then put on the ND.
To produce the pillowy waterfalls look you may not need a very long exposure to capture motion blur. The water is moving so rapidly, and a 3-stop ND filter will work fine in the middle of the day. Getting a similar effect with a seascape, a lake, or slow moving clouds you more than likely want to get to an exposure that lasts 30 seconds or greater, as the sea, the lake and clouds aren’t moving as fast.
The lower light levels of early morning or early evening can help get longer exposures, and light during those times of day are the best light to really shoot in.
Let’s suppose you’re shooting portraits on a really bright, sunny day. Maybe around noon. It is way to bright out and you can’t get a wide enough aperture to control depth of field that would allow you to you get a shallow enough depth of field to soften the background, because it requires a shutter speed that exceeds the fastest available.
Adding an ND filter will enable you to select a wider aperture. To get the creative control you require.
Use the table below to ensure you get the right filter for your needs.
Filter Strength Filter Terminology Common Uses
(in f-stops) Light Reduction
2 4X 0.6 ND → Modest increases in exposure time, such as with waterfalls.
3 8X 0.9 ND → Modest increases in exposure time, such as with waterfalls.
10 ~ 1,000X 3.0 ND → Extreme increases in exposure time,such as blurring in broad daylight.
13 ~ 10,000X 4.0 ND → Extreme increases in exposure time,such as blurring in broad daylight.
20 ~ 1,000,000X 6.0 ND → Extreme increases in exposure time,such as blurring in broad daylight.
Note: the light reduction factors above can also be thought of as exposure time multipliers.
Your best bet for a circular neutral density filter is a variable as stated earlier in this article. That way you can dial in, by turning a ring, the exact number of stops you require for the scene or subject.