How to use filters creatively to improve your digital photography.
By Bob Shell
Many beginning photographers buy their camera and lens and never
consider buying a lens hood, also called lens shade. Sometimes these
come with lenses, but often they don‚t. If you didn‚t get a lens
hood with your lens it is the very first accessory you should add.
are several types of lens hoods, but the most commonly encountered
ones are hard, made from rigid plastic or metal, and soft, made
from rubber. So long as the lens hood is the right length for the
focal length of the lens you are using, all of these work just fine.
Some photographers prefer the rubber ones because they provide extra
shock protection to the front of the lens. If the lens hood is the
wrong length for the lens it will not provide very much flare protection
(if too short) or will cut off the corners of the image (if too
long), so buying the right one is important. In many cases your
lens instructions will specify the proper hood. If not, your best
bet is a knowledgeable sales person at a good camera store.
purpose of a lens hood is to block light from the lens that is not
contributing to the image. Excess light from outside the image area
can cause problems if not blocked. This will be seen as an overall
gray cast over the whole image and a loss of contrast in the image.
You may also get ghost images and reflections caused by stray light
bouncing around inside the lens. In the worst cases you will lose
all detail in the image. The technical term for this is veiling
glare, and a proper lens hood will greatly reduce or eliminate it.
There are two schools of thoughts about filters for digital photography.
Some feel that there is nothing you can do with a filter on the
camera that you can‚t duplicate after the fact in Photoshop. The
other school of thought, to which I proudly belong, believes that
there are many effects produced by photographic filters which can
not be duplicated in software after the fact. Of course there are
many effects which can be done with Photoshop or plug-ins which
can‚t be duplicated with lens filters.
is a lot of confusion about just what filters are and just what
they do among beginning photographers. Many think that they somehow
add something to the image that wasn‚t there in the subject. Just
as with filters used to clean water, remove unwanted things from
gasoline, etc., photographic filters follow the dictionary definition
of a filter and only remove things. What they do for us in photography
is remove unwanted types or quantities of light. If the light falling
on your subject contains too much of a particular color of light,
say it is too blue as an example, then you want to use a filter
on your camera which will subtract the excess blue to give a natural
look to your photographs. Color altering filters are most effective
when you are using film, but in digital photography you can generally
deal with color casts by setting the proper white balance.
times you will be told by camera store clerks or read in books that
you should always keep a filter on the front of your lens to protect
it. Except in severe conditions like blowing sand, salt spray from
ocean breakers, industrial environments, and a few others, this
is bad advice. Camera stores often push filter sales because filters
are very high profit items and when they add filters and other accessories
to a sale they may well make more on the filter and accessories
than they do on the camera. Even the best filter degrades image
quality slightly, cheap filters a lot more. Because I want the sharpest
possible image I want nothing between my lens and my subject but
air. Generally speaking, if you are concerned about protecting the
front of your lens against impact damage, a good lens hood will
do a better job of protecting the lens than any filter. A filter
also adds two new surfaces which must be kept clean, and two additional
surfaces which may reflect light and cause image degrading flare.
Professional photographers know all this, which is why you will
not see filters on the front of their lenses unless put there for
a specific purpose to modify the image. If you must put a filter
on the front of your lens, insist on only the very best. Nothing
can kill the quality of a great lens faster than a poor quality
filter on its front.
brief filter guide that follows is intended to give you information
on the most commonly encountered types of photographic filters.
It is not intended to be inclusive as there are many other types
of filters for special photographic purposes. For additional information
on filters you can check the web site at the end of this article.
and Sky 1A Filters
UV (also called Haze) and Sky 1A (or Skylight) filters serve two
purposes. Both filter out excess UV which can cause a bluish cast
when working at high altitudes. Since the cement used in almost
all modern photographic lenses is designed to absorb UV, a UV filter
is unnecessary except when working at high altitudes. If you are
working in situations in which damage to the front element of your
lens is likely, a UV filter can provide protection. I use them when
working in the desert on windy days, when working close to the ocean
when waves are high and generating a lot of salt spray, when photographing
inside some types of factories, etc.
1A (Skylight) filter is a UV filter which is also tinted pale pink
or salmon color. This removes some of the blue from a scene and
gives a warmer color balance to the images. Some people find they
prefer the rendition of flesh tones they get when using a Sky filter.
Some filter makers also produce Sky or Skylight 1B filters, which
have a stronger pink or salmon tint.
Sometimes very hazy skies will cause loss of distant detail due
to UV reflected from the haze. In such cases the stronger Haze-1
filter may help bring out detail as in these examples.
are also other special UV filters for situations in which the light
has a very high UV content. These would mostly be used at very high
The polarizing filter is one example of an optical filter which
produces an effect which can not be duplicated after the fact.
falling on subjects gets reflected off and bounces around in all
directions. We see some of this light as reflections and glare.
The light falling on subjects is unpolarized which means that the
wave property of light has modulations in all directions around
the line of its travel. The light reflected from most subjects (except
polished or plated metal) becomes partially or wholly polarized
when reflected, meaning that the wave modulations are mostly or
completely on one axis. A polarizing filter allows light to pass
through which is modulated only on one axis and absorbs light modulated
on all other axes. This absorption is why a polarizer looks darker
than a clear filter.
rotating the polarizing filter you can select which light passes
through it to form your image. If there is an annoying reflection
from glass, water, etc., in the scene, you can filter out all or
most of that reflection because the light forming it was polarized
when it was reflected off the surface. You can eliminate all of
the reflection or only part of it by careful selection of the rotation
angle of the filter. Because a lot of the haze in a blue sky is
made up of reflected light, which also has become polarized in being
reflected, you can make a blue sky bluer by selecting the angle
of the polarizing filter. You can see the effect as you turn the
filter if you have an SLR camera.
are two types of polarizing filters available and many people are
totally confused about them. A basic polarizer as described above
is referred to as a linear polarizer. Linear polarizers are also
what are used in polarized sunglasses. They act simply, filtering
out light modulated on all but one axis. And the light which passes
through them is polarized on that axis. Such a simple polarizer
was fine for simple cameras, but today‚s cameras are not simple.
They employ their own polarizers internally in their light metering
and autofocus systems, and putting a simple linear polarizing filter
on the front of one of these cameras can cause errors in exposure
and focus, or disable both automatic metering and focus. For such
modern cameras a second type of polarizing filter was developed,
called a circular polarizer. A circular polarizer is really two
filters on top of one another in a single ring. The first one is
a simple linear polarizer as described above. The second one (called
a quarter wave plate or Kasemann plate) takes the light passed through
the first one and converts its linear polarization into circular
polarization, or more simply it depolarizes it. This does not lose
any of the effect from the polarizer because the light has been
fully polarized prior to passing through this depolarizing plate.
don‚t need to know the technical stuff, though, to use a polarizer.
If your camera has through the lens metering and/or autofocus, as
almost all do today, you will need a circular polarizer.
filters are also available in neutral, which do not change the color
balance of the scene, and warm polarizers which produce a warmer
photos show the effect of a circular polarizer on reflections. Note
that you can hardly see the woman in the first photo. She is clearly
visible in the second photo after the photographer rotated the polarizer
until the reflections were eliminated. The third photo shows the
effect of a warm polarizer.
The effects of color correction filters can, in most cases, be duplicated
in the computer, and they are not used to much in digital photography.
There may be occasions when you prefer to produce these effects
at the time of shooting, though, so it helps to be aware of what
these filters do. You can also accomplish similar effects with custom
white balance on your camera and set the white balance with special
colored cards (www.warmcards.com).
we want to change the mood of an image by making it warmer or cooler
than it appears in reality, or to correct for color casts in the
light falling on the subject. This is where the filters in the 80,
81, 82, and 85 series are useful. As with the Sky filters mentioned
earlier, these filters come in more than one strength, denoted by
A, B, C, etc., B is stronger than A, C stronger than B, and so on.
The lighting used in most homes is provided by ordinary light bulbs
which use a tungsten filament. For this reason we refer to this
as tungsten light. The 80 series of filters is for use in balancing
photos to provide natural-looking color when exposed under this
type of light. The 80A filter is for use with home lighting while
the 80B is for use with photographic flood lamps.
85B and 85C
These filters do just the reverse of the 80 series, and are intended
to allow you to use tungsten light balanced film outdoors in daylight.
81B, 81C and 81EF
This series of filters is used to correct for the cool effect we
often see in natural light outdoors in shadows or on heavily overcast
days. Also useful with some types of electronic flash which have
too cool a color balance.
These filters, sometimes called Morning and Evening filters compensate
for the overly warm color balance encountered early in the morning
or late in the afternoon.
These filters are designed to correct color when photographing under
fluorescent lights which often produce an unpleasant green cast
in photos. FL-D is for use with daylight balanced film and FL-B
is for use with tungsten balanced film.
Neutral density filters are simply filters which absorb all colors
of light. They are used to reduce brightness in very brightly illuminated
subjects. They are also very useful when you want to use a wider
lens aperture to reduce depth of field when working outdoors in
bright light. They come in a variety of densities for more control.
The 812 filter is only available from Tiffen. It is a special warming
filter designed specifically to improve skin tones. It is particularly
useful in the shade and on heavily overcast days.
special filter makes reds, oranges, rust browns, and similar colors
brighter while having a minimal effect on other colors. It is particularly
useful when making photos of autumn foliage.
Fog filters are available in different strengths and are used to
create the illusion of fog and haze when none is present. They can
produce very romantic effects when used with care, but tend to produce
clichés when used without care or too often. The photos below were
taken using the Tiffen Double Fog filter, which produces a stronger
Sepia filters can produce a romantic, old-fashioned look in color
photos, adding a warm brown look to the image.
We‚ve all seen these used, and overused, on television. They produce
pointed stars of light wherever there is a specular highlight on
the subject. They can be good for lights at night, sparkly jewelry,
and other subjects with sparkle.
These are often called filters, so I am including them here. Actually
they are not filters at all but high quality magnifying glasses
in threaded rings so they can be screwed onto the front of your
camera lens to allow it to focus closer. They produce excellent
results for general photography and are a much less costly alternative
to expensive macro lenses, particularly for the photographer who
does not specialize in close-up work but wants to extend the close-up
capability of the camera occasionally.
Special Effects Filters
While most makers of filters offer some special effects filters
in their line, they have not really specialized in them. Tiffen,
on the other hand, has devoted much time and research into developing
their line of professional special effects filters which were originally
used by the motion picture industry and television production. Many
of these special filters are also available for the still photographer
and amateur cinematographer/videographer. The filters described
below are from the Tiffen Hollywood/FX series.
These are specially designed filters which produce a softening effect
without destroying subject detail. You‚ve seen many of your favorite
actresses through them over the years. They de-emphasize facial
lines and wrinkles. They are also good for providing a glamorous
mood in outdoor scenes. Below is an example of the Pro-Mist 2 filter.
This filter somewhat emulates the effect of shooting through a black
mesh scrim, often done in films, or stretching a piece of black
stocking over the front of a lens. It is more subtle than the Pro-Mist
and Warm Pro-Mist filters. It tones down highlights and lowers contrast
but does not lighten shadows as much as the regular Pro-Mist filters.
Sometimes the effect it produces is described as a pastel effect.
are also „warmš Pro-Mist filters and a „warm blackš that combines
a Black Pro-Mist filter with an 812 warming filter.
A special type of softening filter which smoothes over fine detail
without affecting larger detail in the subject. It creates a softer
look without looking mushy. As with others the Soft/FX is also offered
in Warm Soft/FX.
Often you are faced with situations which are just too contrasty
for the film to capture and you know you will end up with washed
out highlights with no detail, blocked up shadows with no detail,
or in the worst cases, with both. Contrast Control Filters lower
the overall contrast of a scene without softening it, bringing the
contrast range of the subject within that of the film. The one I
use when faced with this situation is the Tiffen Ultra Contrast
which is so unique that it was given a Technical Achievement Award
by the Academy of Motion Picture Arts and Sciences. This filter
is very popular with motion picture and television producers.
These are special variations on the common star filters mentioned
above. There are four versions, North Star, Hyper Star, Vector Star
and Hollywood Star, named for the types of stars they produce around
highlights in the image.
more info on filters: http://www. tiffen.com