Filters are marvelous tools that, in the very least, protect your camera's lens, and at best, can enhance the colorful nature shots your eye sees, but your camera struggles to capture. But there's more to lens covers than just filters, there's also attachments, matte boxes and controllers. This buyer's guide looks at the hardware for lens attachments; to find out more about lens filters software, read our associated story:Hollywood Effects Software Filters and Plug-ins Buyer's Guide.

Filters

Filters are made from glass or plastic, and can be screwed onto the front of a lens (round filters) or dropped into an adapter (square filters). There are a wide variety of filters, along with reasons to use them. We'll take a look at several.

For corrective use, there are filters such as neutral density (ND) or polarizers to help cut down bright light situations. Even if the camera has built-in neutral density filters, it's wise to have a couple of filters. Shooting outside can present color and brightness challenges, and if the built-in ND filters aren't cutting down the light enough, use a polarizer before adjusting the iris settings. Polarizers are also great for cutting down reflections from objects or even water.

Contrast reduction filters, such as a Pro-Mist, can cut down on the blacks, and are commonly used for glamour shots (video and photo), movies and more. Contrast filters (ultra, low and soft) helps to cut down on highlights and bright spots, while bringing out more of the shadows and blacks. These can also be used creatively as a special effect filter.

There are some camera operators and digital cinematographers who prefer to use color balance filters instead of using the camera's white balance feature. The filters come in both CTO (color temperature orange, to use with outdoor light, 5600K) and CTB (color temperature blue, to use with indoor light 3200K).

Another common type of filter is the grad or graduated, where the lens has a darker color (be it for neutral density or creative use) near the top and either gradually fades to clear, or will be split 50/50 between color and clear. A neutral density grad is commonly used to cut down light in the sky, while preserving the horizon and objects or people near the bottom of the shot, which may not be getting as much light.

Special effects (or creative) filters can create all sorts of cool images when used with a video camera. There are color filters, star (a light source in the image will look like a star or sparkle), center spot (keeps the center clear and in focus, while the outer portion is softer), vignette (creates a shadow around the edge of the frame) and diffusion (creates soft focus).

Lastly, there are filters that can protect the camera lens from getting scratched or bumped, while remaining on the lens at all times. They include the UV filter, which also helps cut down slight blues in shady areas or overcast skies, and the clear filter. If you aren't carrying your camera with the lens facing backwards, start doing it. That's the easiest way to protect the lens from potential damage.

One additional note when deciding which filter to buy, be it glass or plastic. While plastic units may be sturdier and more affordable, they tend to get damaged easily, warp over time due to temperature differences and can sometimes be slightly hazy due to the material it's made from, which is picked up by a camera.

Adapters

A terrific way to use filters are with adapters, such as a matte box, which attaches to the front of a lens, and features several adjustable sunshades (or French Flags), which help block light from the top and sides. The matte box is also held to the bottom of the camera via rods and a camera base plate. Manufacturers include Century Precision Optics, Kenko, Sunpak and others.

Square filters, with dimensions like 3x3" or 4x4", can then be attached to a filter holder, and dropped into the matte box from the top. Another advantage of using a matte box is the ability to stack filters, which essentially means putting more than one filter and holder into the matte box. Stacking filters can also cause issues with the camera's light sensitivity or cause vignetting (shadows along the frame's edge), since you're putting numerous glass filters in front of the lens.

A more affordable solution to the matte box is a filter-holder system. Video professionals, aficionados and digital filmmakers can purchase an affordable Cokin standard or pro holder, which attaches to a lens with a corresponding diameter.

From there, a wide variety of filters can be dropped into the holder. Finally, if your camera doesn't have threads to screw on a filter, don't despair. Cokin is one of several companies that makes magnetic filters designed for smaller consumer cameras.

Step Up, Step Down

Let's say you find an affordable set of screw-on glass filters, including a nice polarizer and two or three creative filters. The price is right and the manufacturer is top-notch. The only problem is the camera lens supports only 62mm, while the filters are 72mm. You don't want to let that deal get away, and that's where step rings come in handy. The step-up ring is a screw-on adapter that fits the camera lens, then you screw on a larger filter to the ring, such as a 62mm lens to 72mm filter size. The step-down does the opposite, allowing smaller-diameter filters to be used.

Lens Controllers

Lens controllers allow users to smoothly control the zoom and zoom speeds, and the focus and iris functions of the camera with a remote. The controllers can also set the focus and iris settings to manual or automatic, as well as start and stop recording. Many professionals use a quality lens controller, like those from VariZoom, CoolZoom and DVControl.