244
FANCY FILTERS
Take a closer look at car commercials nowadays. Most will show
The effect is pretty and also performs an important technical
function: in the real world the sky is usually much brighter than the
ground. Cameras with automatic exposure will split the difference
between the sky that's too bright and the ground that's too dark
leaving your car and roadway in murky shadows. The solution is to
open the lens iris and overexpose the sky. Now the car and foreground
look great but the light blue sky has turned to chalky white. Enter
the graduated filter, a piece of glass that is colored at the top and
clear at the bottom. By positioning the camera and glass correctly,
the sky will be darkened by the filter while hubcaps and road dust
still glisten in the sun.
A neutral gray graduated filter will simply darken the sky while
a blue filter will artificially make the sky blue. It's popular
nowadays, especially in desert shots, to use a reddish or coral
graduated filter making the scene look like it was shot at sunrise or
sunset or in the searing heat or in the glow of a nuclear bomb blast.
This is just one example of how a filter can solve a technical
problem while adding some flavor to a scene.
Must-have filters -
If you have no filters, other than the color temperature
correction filters built into your camera, ask yourself: Am I an
ENG-type person that shoots and runs, using a filter occasionally just
to solve problems, or am I the kind of person who paints each image
like an artist playing with the colors and highlights until they are
perfecto? If you are the first type of person, you'll probably need
the following:
1. UV (ultraviolet) or skylight filter --- These two slightly pink
filters are similar enough to be considered interchangeable, so you
only need one or the other. Both make hardly any difference at all in
your picture although they slightly reduce blue atmospheric haze in
seaside shots and in long panoramic shots at high altitudes. Their
main job is to protect your expensive coated lens from water spray,
sand, fingerprints, dust, and nearby sneezes. Ocean air is filled
with salty sprays. The geysers at Yellowstone emit a mist of
mineralized water; the silicates in the water stick to the glass in
your lens like glue when the spray evaporates. When the skylight
filter gets smudged or fogged, just remove and wash it, something you
cannot do with a $2000 camera lens. And if the skylight filter gets
scratched, pitted, or hopelessly dirty, just throw it away and install
a new one. They are not expensive. If the perfectionists among you
are still debating over the choice between skylight and UV filter,
here's the difference: The UV filter is just a tad pinker, removing
more of the ultraviolet light than the skylight filter.
2. Polarizing filter --- This filter reduces shine and glare. It can
darken a sky while leaving the clouds just as white as before (unlike
a graduated filter) thus exaggerating the brightness of the clouds.
Polarizing filters reduce the shine in water making it easier to see
through the water revealing fish, fauna, and deep blue colors below
the surface. Polarizing filters erase the shine from windows making
you better able to see through the glass. Polarizing filters change
the white shine of hot pavement back to the original black tar. In
car commercials polarizing filters reduce the glare from chrome and
shiny paint, accentuating the deeper colors.
Remember that a polarizing filter, in order to work correctly,
must be rotated to a certain position. Make this adjustment before
you start the shoot. You may find it handy to place a mark, perhaps
with White-Out, at the top of the lens filter when it is in the most
effective orientation. Once you have found this "best" position for
the filter, you will find that most other shooting circumstances will
call for the same orientation. With a highly visible mark at the top
of the filter, you can position the filter at a glance rather than
experimenting with it for each shot.
Remember that some lenses rotate as you focus, and the filter,
if screwed onto the outside of your lens, may rotate with the lens,
changing its orientation. By not screwing the filter on tightly, you
can hold it between your thumb and forefinger, holding it steady while
the camera lens rotates. Some polarizing filters rotate separately
from their screw threads allowing them to move freely even though the
mechanism has been threaded tightly onto your lens. There is another
solution to this rotating lens dilemma that I'll get to shortly.
3. Neutral density graduated filter --- As mentioned earlier, TV
cameras don't like high contrast ratios. Bright things and dark
things cannot both look good in the same picture. One solution is to
aim some extra light at the darker parts of your picture, a process
that requires extra lights or reflectors. A second solution is to use
a graduated filter so that the bright part of the picture gets dimmed
by the dark part of the filter. The neutral density graduated filter
is usually used to darken a bright sky, but it can be rotated 90°
and
used to darken a brighly lit street on the left side of the picture
while someone is lurking around a shadowy corner in the right side of
the picture.
4. FLD fluorescent filter --- Professional cameras are equipped
with built-in filters, selectable with a thumbwheel or switch. The
simplest models have simply INDOOR and OUTDOOR positions, while better
models have various color temperature settings, including fluorescent
color temperature. If your camera doesn't have this setting, you'll
rue the green tinge fluorescent lights impart to your shots.
Solution: Slap a slightly pink FLD fluorescent filter onto the lens
to banish the green ghoulies.
5. Blue 80A or 80B filter --- Same situation as above, if your
camera lacks the built-in filters to maintain proper colors when
shooting indoors with common incandescent lights, slap on the blue
filter to get the red out.
The above filters cost about $20 - $50 apiece and can screw onto
your lens where the lens hood used to be. You then screw the lens
hood onto the filter. Naturally, the filter has to be the right size
in order to fit your camera lens. Camera lenses are measured by their
diameter in millimeters, so if you know your camera's lens size you
will be able to locate a filter. Examine your lens, especially around
its outside rim to see if the diameter is printed there, usually a two
digit number followed by mm (millimeters). Most lenses range from 43
to 77 mm. Don't confuse the lens diameter with the lens focal length,
also measured in millimeters. If in doubt, you could always take your
lens to a camera store to see what fits. If you cannot find exactly
the right filter, but something close, or if you already have filters
from a previous camera, you can buy a stepping ring which will have
one set of threads to fit your camera lens and another set of threads
to fit your filter marrying the two.
Fancier filters -
The second category of videographer is the artist, one who would
stock a number of specialized filters. You could buy the glass
filters separately, each mounted in its own threaded ring, but that
becomes expensive. The solution here is to buy a filter holder oe
matte box that attaches to the outside of your camera lens. The
holder has slots allowing you to drop unmounted glass filter squares
into the holder. The holder accommodates several squares at once so
they may be teamed up for a cumulative effect. The unmounted squares
are cheaper than the round, mounted lenses, but their big advantage is
that they don't rotate with the lens. The holder stays in the same
position while the camera lens rotates, allowing polarizers to remain
properly aligned, and graduated filters to keep their orientation.
You may ask yourself why bother with fancy filters if you can
just run your video signal through a special effects device and add
color or whatnot to the image in post. That's a fine idea if you have
lots of time and really know your colorizers and paint programs well.
Personally, I'd rather slap a piece of glass in front of the lens and
know exactly what I'm getting instantly. You can make a star twinkle
without rendering a single frame, or add color in a perfectly smooth
graduation (as opposed to those steppy backgrounds you get with low
cost digital effects gadgets). And just try to make a keyhole or
binoculars vignette on your Toaster; it can be done, but not in the
nine seconds that it takes to drop a filter or cutout in front of the
lens. Just think of the copying and pasting you'll be doing with your
computer in order to create multiple images, especially if they rotate
around the central image. Filters are great because they are simple
and fast.
Sales pitch over, here are some of the fancier filters that may
find their way into your camera bag.
'Twas a dark and foggy night -
Fog filters soften sharpness and moderately lower contrast while
causing bright parts of the picture to glow as if surrounded by a
vaporous mist, cloud, or smoke. While David Speilberg makes mist the
hard way by blowing fake smoke onto the set and shining lights through
it (he loves this shot, you find it in nearly every one of his
movies), it's easier (albeit less dramatic) to slap a fog filter onto
your lens and dress your actors in damp slickers. Light streaming
through windows or emanating from headlights exaggerate the fog effect
with a visible flare. Normally lit scenes with subdued highlights
will show very little effect. Double fog filters approach the
consistency of wax paper and achieve pea soup fog. For this effect to
look most natural, employ overcast gray lighting.
In a pinch, you can make your own fog filter by spritzing
dulling spray or a soap solution onto your skylight filter. Bug spray
or deodorant spray will also work. Although these quick and dirty
methods will fog your lens, they tend to reduce picture sharpness,
something the professional fog filters avoid to a large degree.
Low contrast filters, like fog filters, also reduce contrast
(hence the name) but maintain a sharper image than their foggy
brothers. Low contrast filters lighten shadows, leaving the bright
parts of the picture untouched (no glowing halos). Unlike fog filters
where you want the effect to show and therefore light the scene to
emphasize the effect, low contrast filters are subtle. They may bring
excessive contrast in a picture down to where your camera can easily
digest it. In normal scenes, a low contrast filter may created a
smoky look to a room making the image less stark and more dreamy.
Soft contrast filters work the opposite of low contrast filters;
they darken the highlights while perserving the darkness of shadows.
Like their low contrast brothers, soft contrast filters also produce a
more usable contrast range for your camera.
Diffusion filters reduce image sharpness without making the
image appear fuzzy. They are great for removing distracting details
such as wrinkles in facial close-ups. Denser grades of diffusion
filters create soft dream-like scenes.
You can make your own diffusion filter by stretching a nylon
stocking or a fine silk mesh over your lens. If the mesh is white, it
will also lighten shadows. If the mesh is dark, it will reduce
highlights. The finer the mesh, the less obtrusive the effect. The
mesh should always be held close to the lens; the farther it is away,
the more it intrudes into your picture. Keep your lens iris medium to
wide open to minimize the chance that the lens can focus on the
strands in the mesh.
A mesh works by defracting light, bending it out of the image
plane. Tiny details like wrinkles are like single bullets being
deflected by the winds; they don't hit their target and disappear.
Larger objects, such as eyes and other facial features, are like an
army of guns firing bullets at the target. Even though some bullets
may drift, 99% hit the target and stay visible. Thus, net-type
filters erase blemishes without making the rest of your image fuzzy.
Nets can come in various colors to warm up shadows (red nets) or
enhance flesh tones (skin tone nets). Then there are hair nets to
keep your fleece out of your food, and fish nets to trap tuna. Keep
this up and a net will be waiting for me somewhere.
Star filters make points of light look like stars. Their effect
is hardly noticeable in normally lit scenes. Dark shots with bright
lights in them, especially sharp points of light, will display a
number of spokes coming from the light. This filter is manufactured
by finely etching lines in the glass to defract the light to form the
stars. If parallel grooves are etched in one direction, you would get
a two-point star which looks like a streak, great for enhancing the
appearance of movement. Etching lines in several directions create
more points to the stars, allowing 4, 6, 8, and 12 point varieties.
When the lines are etched closer together, the stars appear fatter,
appropriate for accentuating the flair flamboyant stage lighting.
Wider spacing produces finer more delicate stars.
In a pinch, you can make your own star filter by wiping a fine
film of oil (perhaps from touching your nose with your finger) back
and forth across the skylight filter. Make parallel lines with your
finger. Then wipe your finger across the lens perpendicular to the
first set of lines. This should make a 4-pointed star. You could
then draw an X adding two more points to the star. Be very sparing
with the oil; the effect is quite pronounced.
A center spot filter will create an image that is sharp in the
center and something else around the periphery. A center spot with
fog, will create a dreamy halo around someone's face. The outside of
the picture could be fuzzy, diffused, out-of-focused, or colored
depending on the filter. Wedding videographers use these filters when
shooting those maudlin romantic kiss shots with the bride and groom
smooching in the center while the rest of the picture goes dreamy.
You could try making one of your own center spots by smearing a
small amount of hand soap in a circle around your skylight filter,
avoiding the center of the lens.
Through rose colored glasses -
Colored filters create the obvious effect of changing the color
of the scene. A cool, blue mid morning shot of a ship at sea with the
sun in the background can be turned to a glowing warm sunset shot with
the addition of a sunset or orange filter. A blue filter will make
the shot colder, almost arctic. Yellow, red, emerald, tobacco, mauve,
pink, and coral are all popular colors for spicing up a dull old shot.
Sepia filters add a touch of warm brown to your images. Why
would you want to do that? Old turn-of-the-century black-and-white
photos had a sepia color to them. If you were shooting video tape of
a black-and-white photo album, sepia color would give that familiar
antique look to the image.
Although solid colored filters are inexpensive and quick to use,
it is fairly easy to get along without many of them. If you bring
colored sheets of paper with you on your shoot, you can white balance
your camera aimed at one of the sheets. Make sure your camera's
CONTINUOUS WHITE BALANCE is switched off so that your camera doesn't
reset itself when you turn away from the colored page. The camera
will now see the world with a tint opposite to the color on the page.
The same trick will work if you have a couple of colored filters and
white balance your camera through the colored filter. When you remove
the filter, the camera will see the world in a color contrary to your
filter.
Filter tips -
Less is better. Although you can stack filters, combining their
effects, the added glass increases distortion, decreases brightness,
contrast, and edge sharpness in your picture. The multilayers of
glass may combine to create faint rainbows or Newton's Rings, and nets
and star filters may combine to create moire, faint bands or shadowy
dots across the picture. Use the fewest filters possible. Also don't
forget that your camera may be adding its own filter to the equation.
Switch the camera's filter wheel to CLEAR or OUTDOORS to remove it
from the path. This is especially important when you are using 80A,
80B, or FLD correction filters.
Filter threads are delicate. Take care not to crossthread the
filters when screwing them on. Also beware of glass thickness; you
don't want to have any glass pressing against other glass as you
tighten the filters. And tighten filters gently; you don't want them
freezing up.
If you failed to heed the above caveat and cannot remove a
seized filter, try these maneuvers: Screw your lens shade onto the
filter. Put the lens cap on. Using the bigger "handle" of the lens
shade (stiffened by the cap) and wrapping the web of your thumb around
the filter/shade combo, give it a twist. The lens cap trick also
works for unscrewing seized lens shades, especially the rubber kind.
If that doesn't work, try this: Drape the filter with a tissue or rag
to keep your sweat off the glass, then press your whole palm against
the filter ring, leaving the ring's imprint in your palm. Now twist
gently.
Mounted filters come in their own plastic boxes to keep them
from getting scratched. Use the boxes. If you have so many filters
that this is a problem, then screw them onto each other making a big
stack. To protect the end filters, go to a camera store and buy metal
caps to fit the rear threads and front threads of the last and first
filter. "Stack Cap" is one brand name of caps. To use a filter,
simply unscrew the drum at the right spot, remove the filter, then
reattach the drum halves.
Anybody can shoot a picture. An expert works in many dimensions
at once, some obvious and some subtle. By using filters, a mood can
be created that adds dimension and realism to the story. Like a
painter, the camera operator can exaggerate or tone down various parts
of the picture, taking total control of the message. Considering the
cost of all the electronics you can buy, and the learning curve you
must endure to master these gadgets, filters are an easy way to make a
big difference with a small budget.
NOTES:
Tiffen markets an excellent videotape, "What Filter Do I Use"
comparing the effects of their various filters. The VHS tape costs
$25 at many photo shops. If you can't find one in your area, B&H
Photo, 119 W 17th Street, New York, NY 10011 sells copies.
TABLE 1
VIDEO FILTER MANUFACTURERS AND SUPPLIERS
Allegro
Zenith Access
1900 N. Austin Avenue
Chicago, IL 60610
312-745-5140
Ambico
50 Maple Street
Norwood, NJ 07648
201-767-4100
Argraph
111 Asia Place
Carlstadt, NJ 07072
201-939-7722
Eurotech Electronics
2 Industrial Park Road
Plattsburgh, NY 12901
518-566-9778
Harrison & Harrison
677 North Plano Street
Porterville, CA 93257
Jasco
311 NW 122nd Street
Oklahoma City, OK 73114
405-752-0710
Kalimar
622 Goddard Avenue
Chesterfield, MO 63005
314-532-4511
Kenko
17801 Skypark Circle, Suite B
Irvine, CA 92714
714-251-9646
Minolta
Cokin Filters
101 Williams Drive
Ramsey, NJ 07446
201-825-4000
Philips Accessories
401 East Old Andrew Johnson Hwy
Jefferson City, TN 37760
615-475-0471
Phoenix
112 Mott Street
Oceanside, NY 11572
516-764-5890
RCA Accessories
2000 Clements Bridge Road
Deptford, NJ 08096
609-853-2323
Rosco
36 Bush Avenue
Port Chester, NY 10573
914-937-1300
Sakar
195 Carter Drive
Edison, NJ 08817
908-248-1306
Satter
4100 Dahlia Street
Denver, CO 80207
303-399-7493
Schneider
B & W Filters
400 Crossways Park Drive
Woodbury, NY 11797
516-496-8500
Sima
8707 North Skokie Blvd
Skokie, IL 60077
708-679-7462
Tiffen
90 Oser Avenue
Hauppauge, NY 11788
516-273-2500
Tokina
1512 Kona Drive
Compton, CA 90220
310-537-9380
Yoshida
Raynox Filters
Toshima
P.O. Box 194
Tokyo, Japan 81 3 3987 4730
Zenith Accessories
Allegro Filters
1900 N. Austin Avenue
Chicaco, IL 60610
312-745-5140