I have taken you into the realm of fixing your photos that suck. Suggested you ‘f’ the rule of thirds, even told you that HDR is not for me. Now it is time for a little filtration. Time to discuss what I use in the field to balance my images for a lot of the lighting scenarios that many believe Photoshop is the holy grail of fixes for – time for some neutral density filtration.
On our workshops and tours, we get a ton of questions about using neutral density filters. And while there are something shy of a bazillion of these filters available, we are going to discuss three basic categories of Neutral Density filters: Circular Neutral Density filters, Variable Neutral Density filters, and Graduated Neutral Density filters. We will also discuss some of the subsets within these categories, and mention some of the manufacturers of the most popular styles.
But first, let’s discuss some terms that we will use over and over.
Stop (of light) – In photography, stops are a unit used to quantify ratios of light or exposure, with each added stop meaning a factor of two, and each subtracted stop meaning a factor of one-half. ~ sourced from Wikipedia
Neutral Density (ND) – A filter which allows light to be stopped or removed from its density, but has no effect on the color, hence the term “neutral” in its title.
Screw-on Filter – A filter which is mated to your lens via the threads found on the end of the lens.
Optical Glass vs. Resin – Optical glass, is glass with few to no imperfections and won’t distort light which passes through it. Primarily used on more expensive filters. Resin filters are a more economical way to fabricate filters; while there may be more aberrations involved in a resin filter, they typically won’t degrade your photographs though because the resin is of the quality of the lenses in your glasses (if you wear them).
The Neutral Density Filter
Neutral Density filters are close cousins of the Graduated filters, as they are made from the same glass (or resin) material. Their only differences are size and filter coverage. These are designed to lengthen exposures, allowing you to soften water for example or blur moving clouds. In general, it is a filter that allows you to be creative with your subject matter, and make moving subjects appear flowing and dreamy.
You can find these filters in two basic formats; a version that screws on to your lens (Circular Filter), and one that fits into a filter holder. There are also a number of manufacturers; we are partial to the Singh-Ray line of filters, but you’ll find acceptable filters made by Lee, Cokin, Tiffen, and the newest filter player on the field Breakthrough Photography.
These typically come in the same 1-, 2- and 3- stop increments, but may be found as high as 6- or even 10-stop versions as well, so that you can achieve really long exposures.
Variable Neutral Density Filters
Similar in style to a screw-on Circular filter, the Variable ND filter adds some unique functionality to the design. Much like a circular polarizer, you can rotate the outer bezel of the filter to effectively dial in just enough light stopping power to provide the exact exposure you desire. Typically found in the 3 – 8 stops range (occasionally as much as 10-stops), you are given significant creative control over your image while only carrying one piece of hardware in your bag.
Additionally, the Singh-Ray versions of these filters give you the ability to add a circular polarizer or color enhancer already built in with their Vari-ND filters for more creative control.
Graduated Neutral Density Filters
Imagine if you will…a rectangular glass or resin filter, having only half of the glass coated with the darkening coating. Where a Circular filter allows you to lengthen an exposure by darkening the entire visible area of the photograph, a Graduated Neutral Density Filter allows you to even out exposure in an image.
As you know, when shooting a landscape the sky portion of the frame is typically one to three (and occasionally more) stops brighter than the foreground elements of the frame. By holding the graduated filter to the front of your lens with the dark line at or just below the horizon, you can even out the exposure so that your foreground and sky elements are closer together in their exposure value. Depending on your choices, you will find these filters with two edge definitions: Hard (for a defined horizon) and Soft (for when you prefer a softer blended edge between the light and dark portions of your frame).
Like some of the Circular filters, you can use a filter holder to keep these filters in place for longer exposures, but unlike their Circular cousins, you shouldn’t use a graduated filter in a screw on option. You really need the ability to slide the filtered portion up and down to align it properly with the horizon (or other defining line between the lightest and darkest sections of the frame) to ensure a more even exposure. The screw-on graduated filters only allow for the horizon of your composition to be placed dead center because the division between coated and non-coated portion of this filter runs directly through the middle of the filter. And a dead center horizon very rarely works for dynamic compositions.
As a subset of Graduated ND Filters, you’ll find Reverse Gradient Filters, and Strip Filters. A Reverse Grad filter is almost the same as a standard Graduated filter, but the Neutral Density coating lessens as it gets to the top of the glass which allows the top most part of your frame to remain brighter. A Strip Filter has a strip of color across the center of the filter, for bright sunsets or other images where you only need a narrow, central band of bright light filtered.
NOTE: You’ll find some landscape photographers who no longer espouse the use of these filters, as much of what they do can be done in Lightroom or Photoshop. Jay uses them as a matter of course as he prefers to get as much done in camera as possible.
As you can see, there are quite a lot of options out there that will provide you with some specific, creative tools to ensure that the image you see in front of you is what you see on your screen at home, as it comes out of your printer, or is posted online. Not only will they help your photographs, they are also great to experiment with!
Lee Filters ~ http://www.leefilters.com/index.php/camera/ndgrads
Cokin Filters ~ http://www.cokin-filters.com/creative/filters/
Tiffen Filters ~ http://www.tiffen.com/filters.htm
Breakthrough ~ http://breakthrough.photography
REMEMBER: If you purchase a Singh-Ray filter, use code ‘GOODRICH10’ to receive 10% off your total order!
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