Did you know that Ansel Adams used a lens filter in all of his photographs? It’s true. If lens filters
can do wonders for black-and-white photography, just imagine what they can do for your
video producing.

Lens filters offer a simple way to get better images. These wafers of glass can soften the face of a bride,
fake a sunset at high noon or add sparkle to the chrome on a vintage car.

I asked professional video producer Myron "Buzz" Buzzini to help guide us through the world of lens
filters. With 30 years of image-gathering experience–in both photography and video–Buzz was the perfect
man for the job.

Buzz is a firm believer in the power of lens filters. He first used them with film, but didn’t forget their
usefulness as he made the transition to video.

On a bright Northern California morning, Buzz visited my office with a big bag of filters. We pointed
my camcorder out the window and experimented with each one. In the article that follows, we’ll share some
of the insights that Buzz and I discussed that morning–insights that could help any video creator in their
quest for high-quality images.

What’s In a Filter?

According to Buzz, "A lens filter is little more than a piece of glass that attaches to the front of a
camcorder’s lens." Two basic types of filters are available: round filters that screw onto the front of the
lens, and square filters that slide into a special housing attached to the lens.

The round variety is available in many different sizes. Make sure the lens filter you purchase will fit your
camcorder’s lens–not all camcorders have threads the same size. Generally speaking, palm-sized
camcorders have smaller lens thread sizes, and full-sized camcorders have larger sizes.

Common camcorder lens thread sizes include 34, 37, 43, 46, 49, 52, 55 and 72mm. The thread size is
often marked on the front of the lens. If you can’t find it there, check the specifications page of your
owner’s manual; it’s typically listed under "lens diameter."

Square filters that slide into a special holder–called a matte box–offer an advantage over the round
variety: the filters are all the same size, so only the matte box need be fitted to a particular camcorder lens.
This aspect is handy if you have two different camcorders, or even a camcorder and a 35mm still camera.
You simply buy a matte box for each camera, then use the filters with either unit.

Both the matte box and round filter systems allow a videographer to use multiple filters. With the threaded
type, you simply screw one filter onto another. With the matte box variety, just slide another square filter
into the housing.

Filter Types

With Buzz’s help, we’ll sort through the different types of lens filters and explore applications for their use.
Let’s start with basic filters and work our way to the more exotic species.

"If you only have one filter, make sure it’s a skylight filter," Buzz says. "And keep it attached to your
lens, always."

To the human eye, a skylight filter (also called a haze or UV filter) looks like a
clear piece of glass, but don’t be fooled. This filter does its magic by reducing the ill effects of both ultra-
violet light and atmospheric haze on an image. Equally as important, this filter will protect your expensive
camcorder lens from fingerprints, dust, grime and damage. When you buy a new camcorder, get a skylight
filter, attach it and leave it attached–permanently.

Neutral density (ND) filters reduce the amount of light that enters a camcorder’s lens. They
prevent exposure problems in very bright scenes–like a white polar bear on snow bank on a sunny day, for
example. Available in various densities, these filters work like a pair of sunglasses.

"Neutral density filters are great if you want to blur the background of a portrait-type image," says Buzz.
To do this, simply focus on your subject with a neutral-density filter attached to your camcorder, and–just
like magic–the background obscures into a pleasant fuzzy smudge. The filter forces the camcorder to open
its iris wider, which reduces the depth of field, leaving the background out of focus. Naturally, this works
best when the background is some distance away from the subject.

A polarizing filter eliminates reflections from shiny surfaces like water or glass. These filters
rotate in a specially designed housing; the user simply looks in the viewfinder and twists the filter
until the reflections diminish. It’s quite an amazing effect, when you see it for the first time. They really
work.

Polarizing filters are also great for darkening the sky while making it appear slightly bluer.

Color correction filters perform the same function as your camcorder’s white balance
circuits; they correct the color temperature of the incoming light so your colors will look right, indoors and
out. Since all camcorders now include white balance circuits, there’s not much need for these filters in
video producing. They’re still commonly used in film cameras, though.

Creative uses for colored filters abound. After all, they’re available in almost every color of the
rainbow. For example, a blue filter helps simulate a moonlit night; a sepia filter adds an old-time, historical
look to an image. Have fun, and experiment with plenty of different colors.


Exotic Varieties

The center spot filter is great for portrait shots because it creates a sharp center image
surrounded by a soft, fuzzy border. It’s perfect for romantic wedding images.

The fog-effect filter creates "mist" where none previously existed. These filters will also enhance
the appearance of existing fog. Like many filters, fog filters are available in different grades, or "strengths,"
that alter the intensity of the effect.

A soft-focus filter gives a soft look to an entire image. They’re perfect for facial close-ups
because the filter actually blends away tiny lines in the skin. A warm color is sometimes added to soft
focus filters to enhance skin tones. This combination can actually make people look better than they do in
real life.

Graduated filters are transparent on the bottom and very gradually change to an opaque color on
top. A classic application for a graduated filter is enhancing, or outright faking, a sunset. With camcorder
mounted on a tripod and a graduated amber filter attached, carefully frame the image so that the colored
portion of the filter overlaps the sky. Since the bottom portion of the filter is clear, the lower portion of the
scene is unaffected, while the sunset glows beautifully. If you’re using a matte box filter system, it’s easy to
adjust the filter’s effect by simply sliding it up and down within the housing.

A star filter transforms points of light within an image into brilliant star shapes. These
filters add glamor and excitement to any scene. Be careful not to overuse this filter; the effect will lose its
punch once you’ve seen it a few times.

Avoiding Grime

After placing an accidental fingerprint on one of Buzz’s filters, I decided to ask about cleaning. "Don’t
use window cleaner!" he quickly said. According to our expert, the chemicals in a typical glass cleaning
solution can actually dissolve the coating on a lens or filter. Ouch!

"Also, be sure not to use facial tissue," he added. "Blow off the dust before you begin. You wouldn’t
want to ‘sand’ your lens, would you? That’s precisely what happens when you use a rough facial tissue on a
dusty lens." Special lens tissues and cleaning solutions are available at video and photography stores.

To remove dust from a lens, either use a special brush designed for that purpose, or a blast of air from an
aerosol lens cleaner. Buzz makes a final lens cleaning admonition: "Avoid using eyeglass cleaning
products because they might be too abrasive–eyeglass lenses are usually tougher than camcorder
optics."

Unfortunately, life sometimes throws us challenges–like when your niece graces your lens with a
chocolate-coated thumb print. Of course, you don’t have any lens cleaning supplies handy. What to do?

Hopefully, you have a skylight filter protecting your lens. If so, simply remove it and continue shooting-
-this time, out of reach of your niece.

But what if you don’t have a skylight filter? In a pinch, Buzz says it’s OK to run tap water over a filter to
clean it. Use a soft cotton-fiber cloth to dry. Another option is the time-tested technique of breathing on the
glass, then wiping with a soft cloth. But limit these emergency procedures to lens filters–not expensive
camcorder lenses. You can always buy another lens filter, but replacing the lens on most camcorders is an
expensive and complicated proposition.

If you’re reading this and simultaneously kicking yourself because you’ve broken Buzz’s cleaning rules
for years, hold on before you pitch your expensive optics in the trash heap. Scratched optical coatings are
salvageable–it’s possible to remove the coating and spray on a new one. This service is available through
good video or photography retail outlets and repair facilities.

Filter Care

Most filters come packaged in round plastic cases. These cases are great for protecting filters when
they’re not on a camcorder. But don’t expect a filter to last if you’re in the habit of slipping them in your
pants pocket or throwing them into a camera bag. They’ll become scratched and useless in quick order.

Buzz offers a space-saving alternative for lens filter storage: screw all filters together and put a lens cap
on both ends. This protects each filter, and reduces the amount of space they would occupy if each filter
was in its own case.

What can you do if you can’t unscrew a filter because it’s too tight? Use a lens filter wrench. These
devices are similar to a jaw-type jar opener, and they have the same purpose–to help loosen stuck threads.
Is there a better solution? "Yes. Don’t over-tighten the threads, and keep them clean from grime," says
Buzz.

Buzz recalls a harrowing experience he had while on a back-country shoot. A couple of filter cases fell
out if his shirt pocket, rolled down the hill and vanished into a fast-moving stream. He never saw the cases-
-or their contents–again. The moral of this story? Always stow your gear safely and securely.


Let’s Go Shopping

A quick glance at a deceptively simple filter could give you the mistaken impression that one brand is
as good as another. "Not so," says Buzz. He instructs producers to look for filters that use a threaded
metal retaining ring to hold the glass inside the metal housing. The retaining ring holds the glass against a
small flange on the other side of the housing. Some filters use a plastic device to hold the glass in place;
Buzz doesn’t like this type because the plastic often becomes loose with wear.

Avoid filters with housings made entirely of plastic; these housings may not retain their shape. Also, be
careful to check the quality of filters pitched as an add-on sale to a camcorder purchase.

Shop for filter housings painted matte black; these help to reduce unwanted reflections. And look for
filters that come with storage containers. Shop around–the price can vary widely on the exact same
filter.

A wide range of manufacturers offer a countless variety of lens filters. There are literally too many
different brands and types to mention here. A quick glance through one company’s catalog revealed over
30 different filters available in 14 different sizes–and that’s just the screw-in variety. Generally, the larger
the filter, the higher the price.

If you’re feeling overwhelmed by the huge selection of lens filters, fear not. Some filter companies have
selected a few of their most popular filters and assembled them in pre-packaged kits; these are worth
checking out.

One filter manufacturer makes it easy to sample the world of lens filters before you buy. Tiffen makes
their Hollywood/FX Demo Kit available on loan from participating dealers. The comprehensive kit has 30
different filters including center spot, polarizing, color-graduated and star filters. Also packaged in the kit
is a selection of Tiffen’s versatile Pro-Mist and Soft/FX filters that combine a warming filter with fog and
soft focus effect. The kit comes with adapter rings to fit popular camcorders: 49, 52, 55, 58, 62, 67 and
72mm. Call to see if your dealer is participating in this program.

Cokin offers their Optilight filter kit in 37 and 46mm sizes ($32 regular kit price-$52.99 with polarizing
filter). Four different configurations are available to fit your video producing needs. All kits include a skylight
filter and two other assorted filters which may include neutral density, polarizing, warm color or soft focus
filters.

No Free Lunch

So far, all we’ve talked about are the wonders of lens filters. Is there a downside? Yes.

First off, there’s an optical price you pay when using lens filters. Each additional lens distorts the image
and reduces the intensity of the light that enters your camcorder. Better filters offer less chance of these ills,
but even the best glass distorts the light passing through it a little bit.

While lens filters won’t affect the accuracy of a camcorder’s external white balance sensor, through-the-
lens (TTL) white balance systems may require that you manually adjust the white balance after adding
filters (if manual white balance is available). If you don’t have a color viewfinder, use a color monitor so
you can see the effect of the filter on your image. This is good advice no matter what filter you’re
using.

The matte box filter system is great, but before you buy, make sure it won’t interfere with your automatic
focus system. This is more likely to happen with older camcorders without inner focus lenses. You may
have to resort to manual focusing.

Ideally, you should use lens accessories that directly fit your camcorder’s lens threads. But when that’s
not possible, a myriad of threaded filters are available to solve the problem. If you must adapt, start with
filters that are bigger than your lens. A smaller filter might cause undesirable darkening at the corners of
the image (called "vignetting"). This effect is most noticeable when you zoom to a wide-angle setting.

There’s no doubt that videographers love their high–tech electronic toys. But don’t forget
there’s a simple way to improve images without circuitry–lens filters.

Dave Welton is a community college instructor and freelance writer.

Sidebar 1: Do It Yourself Filters

You may want to experiment with home-made filters before you buy. Here are a few easy-to-build
ideas.

Metal window screen placed in front of the lens creates a star-type effect. The finer the screen, the better
the effect. For best results, use two pieces of screen; rotate them as you watch the image. A rubber lens
hood offers a handy place to tape the pieces of screen. Of course, be careful not to touch the lens.

Create your own center spot filter by applying a coating of petroleum jelly around the edge of a clear
piece of glass or a skylight filter. (Whatever you do, don’t apply petroleum jelly directly to your
camcorder’s lens.) A light coating of jelly usually works best; a monitor will help you judge just how much
image diffusion is appropriate.

You can also experiment with colored gelatin sheets. Place these inexpensive sheets between pieces of
glass; they’re available in many colors through photo stores.

You can even mix-and-match different homemade filters for multiple effects. Have fun!

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