Understanding Camera Lens Filters: A Practical Guide
August 14, 2013
• 0 Comments
With the transition from acetate film-based cameras to digital cameras, the need for camera lens filters has diminished. Though once required for even simple landscapes or the slightest hint of movement, these filters have been replaced by compact, effective single lens reflex (SLR) technology. But the emergence of digital alternatives hasn't erased the need for filters—instead, using the right filter can take your image to the next level.
Polarizing filters reduce the amount of reflected light picked up by your camera sensor. Used properly, they deepen the color of blue skies, improve color saturation, and reduce sky-to-land contrast. The key to using polarizing filters lies in moderation because they limit the amount of light reaching your camera, sometimes by as much as 1/4 to 1/8. If you think this is a type of filter you might find useful, it's important to consider how much can afford to spend on one. Linear polarizers are cheap, but they interfere with the metering and autofocus systems used by SLR cameras. Circular polarizers are more expensive, but they don't impede metering or autofocus.
Ultraviolet (UV) filters don't add anything to the quality of the images you take—and may have detrimental effects because even the tiny abrasions that inevitably mar these filters can lower your photo quality. So why bother with a UV filter? To protect your lens. A high-quality, SLR camera lens can be damaged by consistent exposure to the sun, but a UV filter keeps that lens it in mint condition. Replacing the filter is far less expensive than shelling out for a brand new lens, but you need to be diligent: If image quality starts to suffer, replace the filter.
Neutral Density Filters
When used effectively, a neutral density (ND) filter discards a portion of the light reaching your camera. This loss of light can help give you smoother water movement, a shallower depth of field, or introduce motion blur. ND filters reduce incoming light by between 1/2 to 1/64. They are useful to have on hand, but when buying be aware that there's no consistency across brands in terms of nomenclature.
Graduated neutral density (GND) filters let you achieve a liner blend from light to dark in an image. They may be "soft edge," which blend smoothly from the top of the image to the bottom, or "hard edge," which have distinct transition points. Landscape photos are ideally suited to GND filters, but you must be careful when using them because they can cause excessive lightening or darkening, and vertical objects that extend across the entire frame may look strange—too light at one end and too dark at the other.
The range of digital camera lens filters available will allow you to take better-quality pictures with a very minimal investment. But use them in moderation to take images that capture the spirit of your subject without overly complicating your medium. Put simply, photography is an easy hobby to dabble in, but a difficult profession to master. If this art form really is your passion, consider enrolling in a dedicated program like one at the Brooks Institute, where learning about filters is just the beginning.
Image Source: Wikimedia Commons