are actually two filters used in this shot, made in Botswana at
same watering hole as featured on the cover of Frans Lantings' book,
Africa's Last Eden (no longer available). Because I wanted to silhouette
the elephants, I flipped a graduated neutral density filter and used
a sliver of
its filtration to remove any detail in the foreground, and I used
a Cokin Orange filter to keep the yellow in the sky (I was using
200, which I knew wouldn't hold that color well). Nikon N90s, 17mm,
shot from ground level. (The funny thing is that my picture is orange
while Lantings' picture is pink--two very different approaches.)
many of us are shooting digital, one question I get even more often than
before is: what filters should I use? But that's a question that all
photographers should ask themselves. This article will try to give you
some of my views on filters and their correct use.
filters can be used to:
or decrease contrast
colors or color balance
exposure (partially or fully)
- Add a
In each of
these cases, you're making a change to the scene as it exists in
front of you and the way that film or your CCD will record it. That's
okay. Good photography is all about making the decisions about what you
do and don't want to show an eventual viewer. So, for filter use...
Maxim #18: Know
what you want to change and why.
like an obvious statement, but I'm consistently surprised by how many
photographers, especially amateurs, never follow it. At workshops, for
example, I've seen students watch me pull out a filter, then attempt to
mimic me by pulling out the same (or similar) filter themselves. That's
a recipe for disaster. Why? Because unless you know why I pulled that
filter out and what I'm trying to achieve with it, you're simply making
a random change. You should only be making changes (e.g., lens, filter,
composition, exposure choices) you want to make.
consider the picture at the top of this page. I had just gotten my first
graduated neutral density (ND) filters, and the late Galen
Rowell had showed me how he used them only a few days before. If you
had seen me pull out my graduated neutral density filter, you might have
assumed that I was using it to hold back the sky exposure, their typical
use. Galen happened to be the only other photographer on the ground with
me that evening, and he was perplexed enough by my physical location,
my camera angle, and the filter I had just pulled out to ask me why
I thought I needed the ND (he wasn't using one). When I told what I was
going to do with it, he smiled and said "okay, I was thinking maybe
you hadn't been listening to me."
before we get to what each filter does and why you might want to use it,
remember that you have to a particular reason to use a filter. There's
another reason for this:
Maxim #19: Don't put extra glass or plastic in front of your expensive,
well designed glass unless you need to.
tendency amongst amateur photographers to put UV or Skylight filters on
the front of every lens they own. This tendency is encouraged by photo
dealers, who, as they ring up your expensive new toy add "and you
want a skylight filter to protect that lens, right?"
the dealer asks this is simple: it's a way to increase their profit. Mail
order outfits such as B&H and Adorama have made it difficult for local
dealers to charge list price on lenses (though some still manage). For
example, the markup on a 24-85mm AF-S lens is quite small, meaning that
the dealer might make only $50 on your purchase. The markup on a $30 filter
can be as high as 80%. By selling you that filter, the dealer can make
another $24 on the sale, increasing his profit by 50%.
So the question
is: do you need that filter?
examine why a UV or Skylight filter is usually suggested: it won't change
colors, nor does it lower the amount of light that passes through to the
film/CCD significantly. While most are made of multicoated glass, the
two extra air/glass surfaces will have a slight impact on overall contrast
due to refraction. Some dealers will tell you that you need these filters
to get proper color at altitude, or in bright conditions, or some other
nonsense. But the truth is that film hasn't needed UV filtration for quite
some time now--all modern film stocks have virtually no UV sensitivity.
So what have
you gained by putting a filter in front of your lens? Well,
the other normally suggested reason is "to protect the front element
of your lens from accidental scratching or breakage."
Small scratches on the front element of most lenses don't actually have
much effect on optical performance, though. Indeed, unless the lens is
a very wide angle lens, about the only optical effect a small scratch
would have is exactly the same one as a filter has: lower contrast. (On
wide angle lenses at small apertures, depth of field might be large enough
so that you'd see optical degradation due to a scratch or blemish.) And
if you're going to bump the lens hard enough to create more than a minor
scratch, you're probably hitting it hard enough to bust the filter, and
glass scratches glass pretty darn well in such situations, so I don't
hold much faith in the "protection from breakage" theory.
I don't see much of a reason to put a filter on my lens for protection.
Indeed, I've found that lens hoods tend to do a better job at that, anyway.
what I implied earlier in this discussion: adding a filter to your
lens degrades optical performance. A really well made filter won't
degrade performance noticeably, but it will degrade. Poorly made
or inexpensive filters degrade performance more than well made ones. Every
air/glass (or air/plastic) transition in a lens adds reflections, despite
multi-coatings and quality materials. Every reflection decreases overall
contrast. Some reflections can be insidious in this respect--especially
if light is hitting the front filter surface unevenly.
previous paragraph leads us to yet another conclusion:
Maxim #20: Good filters are expensive.
amused when a student pulls out $10 plastic filters and sticks these on
the front of their $1400+ lenses. What's the expectation here? Unless
it's some cartoon-like effect, this is an almost certain way to lower
the quality of image that your camera can capture.
why good lenses are expensive is that it is not easy to grind glass in
ways that are defect free, and it takes multiple, well-researched coatings
(and expensive glass) to keep colors neutral and focused at the same spot.
You could take a piece of window pane glass and spray something on it
and have a filter. But window pane glass doesn't have a perfectly even
thickness, and what you spray as a coating needs to have known properties
for how it passes light.
obvious of these cheap, cartoon-like filters are the Cokin P graduated
filters. Cokin makes them in Tobacco, Smoke, and supposedly Neutral variations,
as well as a bunch of more bizarre renditions, such as Blue, Orange, and
even Yellow. The name "Tobacco" ought to be a giveaway. Exactly
what color is that? (The filter provides a garish, warm tint in the filtered
area). But the Neutral version isn't neutral. And the Blue version doesn't
just effect blue tones. And so on. I've used these filters for startling
effects, but never if I'm trying for the highest quality and color neutral
seen more expensive, supposedly high quality filters that have problems,
too. In general, I've moved away from Hoya and Tiffen filters and these
days tend to use B&W filters, which seem more consistent in quality
and less prone to unwanted optical "additions." But ask around:
dedicated photographers learn to perceive the differences between a "quality"
filter and one that adds unwanted side effects.
My Usual Filter
P holders. One modified to a single slot (see below). 62mm and 77mm
62mm and 77mm Circular polarizers from Nikon and B&W. 77mm Red/Blue
polarizer from Singh-Ray.
- 2 stop
and 4 stop neutral density filters.
graduated neutral density filters: 2 stop soft and 3 stop hard minimum
kit. Sometimes I'll also carry a 1 stop soft, 2 stop hard, 3 stop soft
and 5 stop hard.
FLD filter for fluorescent lighting.
Infrared filter for special effects.
Step-up rings for lenses I'm carrying with my nonstandard filter sizes
(e.g., 52->62, 67->77).
A Good Filter is:
neutral (unless it is specifically designed to alter a color and that's
the effect you want).
- Made of
high quality glass or resin.
- Is often
multicoated to preserve contrast.
- Not inexpensive.
with a protective case.
a Cokin Holder
Cokin P holders have a tendency to vignette on wide angle lenses (i.e.,
their front edges appear in the angle of view). That's because they have
three slots, and that front slot is a long way from the front element
of the lens. To "fix" this problem, buy an extra holder and
- Make a
cut through the middle of the second slot on each side of the holder.
Discard the portions you cut off.
- Sand the
remaining edge that sticks up on each side so that it is "flat"
with the front of the first slot's holder. (See photo, below)
Cokin now makes a P299 wide angle holder similar to my do-it-yourself version.
Do I Need
to Buy Nikon Filters?
a number of filters, most notably a very nice set of circular polarizers.
Yes, they're expensive, but they're also very high quality. On the flip
side, some photographers don't like the wider front on the polarizers
(made this way to reduce the chance of vignetting), which makes it difficult
to mount additional filters in front of the polarizer.
But to answer
the question the heading asks: no, you don't need to buy Nikon filters
just because you have Nikon equipment.
look at some filters, what they do, and why we might want to use them
(warning: some of what follows may contradict what you think you know):
this category name is a misnomer. An 81A filter is often referred to
as a "warming" filter, but what we're really talking about
are color correction filters. Film is produced to have a response to
a certain color temperature of light (and digital cameras have a white
balance setting to control the same thing). Indoor film is usually balanced
to 3400K and outdoor film is balanced from 5400 to 5600K, depending
upon the type and manufacturer. What the heck are those numbers, you
ask? Well, they're color temperatures of the light measured in Kelvin
(K). Continuous spectrum light produces a balance of the visual range
of colors somewhat dependent upon the black body heat level. Huh? Well,
think of it this way: when you turn the gas burner on your stove on
at a low level, the flame is "orange." As you raise the heat,
the flame eventually becomes "blue." That's the black body
heat level in action: the hotter something burns, the more blue the
light (higher K value). (Note, things like our atmosphere have a tendency
to modify the light value of distant "hot" objects, like the
sun.) "Warming" filters weren't originally produced to provide
redder renditions of your scenes; they were produced to correct certain
lighting conditions to match what film (and today, certain CCD white
balances) were set for. For example, that 81A filter that everyone uses
for "warming," provides a MIRED (MicroREciprocal Degree, a
way of measuring color temp--see pages 42-43 of Nikon
Field Guide) shift of +18. Used in sunny daylight, an
81A would make film respond more as if it had a color temperature setting
of 5000K, rather than 5500K. When you mismatch what actually passes
to the film/CCD (5000K) with what the film/CCD expects (5500K), you
get a color shift. Lower than expected values like this example produce
warmer (redder) coloration. In the "warming" family, the lineup,
from least to most effect is 81, 81A, 86C, 81B, 81C, 81D, 81EF, 86B,
85C, 86A, 85, and 85B. But there are also "cooling" filters,
which have the opposite effect (passing a higher color value to the
film/CCD than expected). From weakest to strongest, these would be 82,
82A, 78C, 82B, 82C, 80D, 78B, 80C, 78A, 80B, 80A. Those of you who've
read the white balance sections in any of my digital SLR books (Complete
D100 Guide, Complete D1, D1h, &
D1x Guide, or Complete S2 Guide)
will probably understand what I'm about to write: unless you know what
your film/CCD is set to record and the current color temperature
of the light you're shooting under, you cannot possibly know what filter
to add to your lens to get the exact warming effect you want. Even worse,
if you use print film, most automatic printing machines will try to
remove any color shift the warming filter adds! There are photographers
who regularly use a particular warming filter on their lenses for every
condition; what they are essentially doing is shifting the color temperature
balance of the film they're using, not warming a particular scene. In
digital with a camera that has decent white balance adjustment abilities
(D100, D1 series are examples), I'll make a blanket proclamation: there
is no reason to use a warming filter; learn how to use
white balance properly instead.
inexpensive; modify colors in known ways
do you know why and how you're modifying color?; really
need a wide variety to fine tune color adjustment
A polarizing filter alters a key property of light. "Pure"
light consists of light photons in a nice, standardized "wave."
But whenever light bounces off of an object (the thing you're photographing!),
side components are added to this wave and it is no longer quite as
well formed. What a polarizer does is strip off some (many) of these
side components. A practical example: you're photographing shooting
down into a body of water. What you normally see (and photograph) are
reflections on the surface of water, and those reflections are really
formed by the side components. Put a polarizer on and adjust it correctly
(see sidebar, at right), and you can often remove most, if not all,
of these reflections. But the same is true of just about anything: if
I'm shooting foliage, for example, I'll often use a polarizer for the
same reason I do shooting water: to remove the random reflections that
reduce the apparent contrast on the surface of the leaf (water).
you control over reflections; tend to increase contrast and color
saturation; can be used to darken bright skies
expensive for a good filter that won't vignette on wider lenses;
polarization effect will vary across scene with wide angle lenses;
some multi-part polarizers are prone to fogging; effect can't always
standard ND filter simply blocks some amount of light from
the lens. You can easily find ND filters in 1 stop, 2 stop, 4 stop,
and even 8 stop values. A good ND filter is color neutral,
it blocks all values of light equally. Singh-Ray now has a variable
effect ND filter (from 1.5 to 10 stops) which keeps you from
having to carry multiple ones, but it is expensive (US$350).
Some uses of ND filters include:
flash sync speeds. In
bright light with cameras that have slow flash sync speeds, you might
not be able to use flash without an ND filter, because you can't set
an aperture/shutter speed combination that falls within that allowed
by the camera. For example, the Fuji S1 had an ISO of 320 and a flash
sync speed of 1/90. By definition, Sunny 16 exposure would be f/16
at 1/320, so how would you manage to use fill flash outdoors? (1/320
is almost 2 stops from 1/90, so you'd need a lens that went to f/28
to get to 1/90.) Well, one answer would be to put a 2-stop ND filter
on the camera, which would drop your shutter speed to a level where
you could use flash.
a slow shutter speed. I
like playing with slow shutter speeds and moving objects. But sometimes
there's more light in the scene than I need, so I put an ND filter
on. For example, it usually takes a shutter speed in the range of
1/15 to show motion on someone walking, so if I were outside with
a D100 (ISO 200) in Sunny 16 conditions, by definition I'd need something
near f/64! But if I put an 4stop ND filter on the front of the lens,
I could achieve something near f/11 at 1/15, which is manageable.
inexpensive; provide additional shutter speed/aperture selection
none other than the obvious one that they let less light through
to the film/CCD.
Neutral Density. A
graduated ND filter has a portion of the filter that's "clear"
and another portion that blocks some amount of light. The idea behind
these filters is that in some outdoor scenes you may encounter lighting
situations that exceed the range your film or CCD can capture at once.
The typical scenario is bright sky and/or background with a foreground
in shadow. While estimates of dynamic range capabilities of film and
CCDs vary (partly due to different tolerances for noise, non-linearity,
and artifacts), I usually say that slide film has 5-6 stops of dynamic
range, Nikon CCDs typically have 7 usable stops of dynamic range, and
print film tends to have 8-9 stops of dynamic range. Yet I frequently
encounter outdoor scenes that have 12 or more stops of difference between
bright detail and dark detail. By using a graduated neutral density
filter, I can hold back the brightest areas in a scene, essentially
reducing the overall range of brightness in the scene. To do so, unfortunately,
means that I need a clear, mostly straight, edge of demarcation between
the dark and bright areas, though. That edge is not always possible
to find, though once you get the knack of what to look for, you'll find
it more often than you'd think. Most graduated NDs come in what are
called "soft" and "hard" variants. These variations
describe the transition area from filtered to non-filtered, with soft
transitions being longer and less abrupt than hard transitions. If you
have a strong, high contrast boundary, such as a horizon with a bright
sky, you'd use a hard edge graduated ND. If you have a boundary that's
less straight or has intermediary values that would make hiding the
transition edge of the filter difficult, you use a soft edge. Graduated
NDs come in a variety of strengths. The late Galen Rowell, who designed
the commonly used Singh-Ray variety, usually recommended that newcomers
to graduated NDs purchase a 2-stop soft and 3-stop hard as a starting
point. (By way of comparison, I have 1-stop, 2-stop, 3-stop, and 5-stop
soft and hard. What I carry with me varies a bit depending upon what
I expect to encounter.) A couple of points are missed by many encountering
graduated NDs for the first time:
versions are useless. The
screw-in graduated ND always puts the transition area dead center
in the frame, which is exactly where you're least likely to put
the horizon or other dark/light transition. And you can't move that
position. Avoid these filters at all costs. They aren't flexible
enough to be useful.
don't always have to use them on level horizons. I
find all kinds of ways of using graduated NDs. I've used them upside
down (see example, top of page), sideways, very close to frame boundaries,
on strong diagonals, and much more. The only thing you need is a
distinct edge between bright and dark.
not easy to position. The
transition edge usually has to be placed perfectly in order to not
be visible in the final shot. But seeing where the edge is positioned
in the viewfinder can be difficult, at best. The secret is to use
f/22 and hold the depth of field preview button in when you're positioning
don't work well with graduated NDs. Graduated
NDs work decently with wide angle lenses because the depth of field
still keeps the transition area relatively distinct (more so at
small apertures than at wide apertures, obviously). With a 200mm
lens, though, even the hardest edged filter transition becomes amazingly
soft due to depth of field blur.
need front elements that don't rotate. Much
like polarizers, it's a lot easier to set these filters if you aren't
fighting the front element of the lens as it turns for focus. Use
graduated NDs on lenses that have internal focus mechanisms and
which don't rotate the front element.
help manage scenes with wide exposure range; available in a
wide range of strengths and transitions
Singh-Ray's scratch easily; need distinct light/dark edge to
position them on; generally prohibit use of lens hoods; can
be difficult to position
fall you'll see articles in the photography magazines about using enhancing
filters to "bring out" the colors of fall foliage. Most of
these filters are designed to over emphasize one color over another,
such as red. While a lot of photographers think of these filters as
something that "makes everything red redder," it's not that
simple. Every one I've seen will change white objects from white to
a slight color cast. In other words, yes, reds get redder, but all other
colors will shift a bit, too, just not as much as the reds. The Singh-Ray
enhancers probably do the best job of avoiding this color shift, but
even they won't keep your whites from taking on a color cast. Thus,
you'd better want the exaggerated color shifts these filters produce.
Yes, they'll emphasize the yellows and reds in the fall leaves, but
if you want to keep the trunks of those birch trees the proper white,
you'll probably be disappointed. Personally, I'd tend to use digital
editing techniques to pull out colors these days. You have more control
and can do so only on selected colors or areas.
you saturate a specific color; give images a "zing"
they might not otherwise have
expensive; other colors may shift, as well; effect can look unnatural
in some scenes
or FLW. Fluorescent
light is a pain to deal with. Not only do the individual phosphors decay
at different rates, but not all colors of light are present. The net
effect is usually that blue-green light tends to dominate and red-yellow
light is present in lower-than-expected amounts. The traditional method
of dealing with "balancing" fluorescent light--besides using
a shutter speed that's a derivative of the AC cycle, such as 1/60 here
in the US--is to use a Magenta filter on the lens. A better solution
is an FLD (daylight tube) or FLW (warm tube) filter. These filters are
better matched to what most fluorescent tubes produce than you'd get
from simply pulling out magenta. (Curiously, they also seem to work
well to fix casts on some glass tints, such as those in cabin glass
of Cessna planes.) That said, I'd only use these on film cameras, as
with digital cameras you're almost always better off shooting a custom
white balance setting.
do a better job than other commonly available filters
always exactly match what bulb produces; don't fix the fact that
not all colors of light are produced by bulb
I deal with
infrared filtration elsewhere on the site,
and I generally frown on the so-called special effects filters (fog, starburst,
rainbow, etc.), as they produce cliché, amateur-looking effects.
Thus, what I've just described are the types of filters you'd tend to
find me carrying in my bag.
typical graduated neutral density filter in Cokin P size. Note
that the filter is longer than it is wide. This is to allow you
to position the transition line between the filtered and non-filtered
portions at almost any point in the image. I've exaggerated the
filter a bit here--it's not that dark.
You Carry Filters?
Good filters come with protective cases, but if you carry a wide variety
of filters, these cases can add up quickly and give you more things to
track. Some photographers use "filter wallets," which hold multiple
filters in a single fold-out case. Personally, I've found that wallets
aren't very protective of my expensive filters--the slide-in, slide-out
process tends to scratch them. The solution I use for screw-in filters
is "end caps." I screw all the filters together into a densepack
and then screw end caps on each end. This puts all my filters into one
spot and keeps them protected, even when I just sling the densepack into
one of my pockets. (see photo, below)
With my Singh-Ray
graduated neutral density filters, I simply use the supplied slip-in cases.
But note that you'll eventually get grit into those cases that's difficult
(if not impossible) to remove, and your expensive resin filters will ultimately
develop scratches. Personally, I simply replace my Singh-Rays every 18
months or so, but you also have to remember that I travel in very harsh
environments and subject my equipment to the elements all the time. You
should get a longer life out of your Singh-Rays than I do.
cameras all require what's known as a "circular polarizer."
I could get technical and describe "wave plates" and other technical
mumbo jumbo to describe exactly what happens to light as it goes through
a polarizer and how a circular polarizer is different from a linear polarizer,
but let's simply cut to the chase: Nikon's autofocus system uses a partial
mirror surface. Linear polarizers produce a light that doesn't survive
the partial mirror bounce down into the autofocus sensors well. Remember
that the autofocus sensors on modern Nikon cameras also contain parts
of the matrix and spot metering systems. Thus, if you don't use a circular
polarizer, in some lighting conditions you can get slower or incorrect
focus and incorrect exposure settings. So, if you own an autofocus Nikon
body, only use circular polarizers. If you are using an older manual focus
body, most will allow you to use the less expensive, regular (linear)
two primary effects you use a polarizer for: (1) to remove light scatter;
and (2) to remove reflections. When you use a polarizer to make a blue
sky darker or to get increased contrast or color saturation, you're removing
light scatter. This effect works best when you are pointing the camera
(and thus the polarizer) at a 90 degree angle to the original light source.
Thus, if the sun is in the East sky, you'll get the darkest blue out of
the polarizer when the camera is facing North or South. (But watch out
for wide angle lenses! Many show enough angle of view that you can see
the variability in the polarization effect across the frame.) The least
effect occurs when you are point the camera at a 0 or 180 degree angle
to the light source.
reflections (off glass, water, etc.), the maximum effect occurs when you
hold the camera 35 degrees to the surface containing the reflection.
usually have one of three filter sizes: 52mm, 62mm, or 77mm. As a broad
generalization of the Nikkor philosophy: physically small prime lenses
tend to use 52mm, larger prime lenses tend to use 62mm, and the professional
zooms tend to use 77mm. A few oddball lenses use different sizes (for
example, the 67mm of the 24-85mm AF-S). Instead
of buying filters for every individual lens you own, Nikkor users can
generally get by with buying two sets: 62mm and 77mm. Buy step-up rings
(52mm-62mm, 67mm-77mm) for the lenses you own that don't match these two
sizes. Likewise, get a Cokin P ring for each lens size you own, plus a
couple of Cokin P holders (one modified, as outlined above). This allows
you to use graduated NDs.