Neutral density filters

Neutral density filters, often just called Neutral density filters, effectively reduce the amount of light reaching your image sensor, but do not affect the color. Why are they useful, you might wonder? In particularly bright conditions, they are very practical and allow you to shoot longer exposures. For example, if you want to shoot a waterfall with a long exposure to achieve a blurring effect, a neutral-density filter allows you to have the aperture open longer than you would if you weren’t using it (see figure 7-6). This can also be really useful when you’re shooting in the snow, and it also enables you to open up your aperture for a more-pronounced narrow depth of field.

Oregon waterfall shot using a 0.6 ND filter offering a 2-stop reduction in light Taken with a Canon EOS 1D Mark III using an EF24-70mm 2.8L USM lens. ISO 100, f/13 for 8 seconds.

A graduated neutral-density filter is one where (typically) one half of the filter is darkened and the other half is uncoated, plain optical glass. You’ll find graduated filters where one half is a specific color, for creating unusual effects, but mostly (and most usefully) they are gray/neutral.

There are a number of uses for these filters, not the least notable of which is outdoor photography. Because there’s often a marked contrast between sky and earth in a landscape shot, for example, using a neutral density filter where the upper half of the filter is used on the sky (which is brighter) and the lower part on the earth will help even out the shot for a more consistent exposure throughout. This allows you to have more detail in both areas. Often, using a neutral density filter and shooting in RAW produces a very wide range of tonality that provides nearly endless editing opportunities.

When using a graduated filter, the best way to determine your exposure is to meter without the filter on the lens and fill the frame with that area. Use this as a starting point for your exposure when you put the filter on the lens and shoot both the ground and the sky, and then make adjustments after you’ve taken some test shots and see what happens.

Category: Filters

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