'A polarised view of the world
Getting to grips with lens filters and their use
By Rob L. Suisted
in New Zealand Outdoor magazine)
about 2 days walk from anywhere, and drop and lose an expensive
lens filter into a decent sized mountain stream, you tend
to appreciate it’s value somewhat more. Not just the
dollar value, but also the added value these little glass
gizmos can make to your photography. Such was my luck over
the Xmas break. should anyone find such an item in the head
of the Douglas River, Westland - it’s yours.
Let’s now take the opportunity in this column to look
at the real benefits that lens filters can bring to your photography.
I’m sure most people use filters, whether it is the
humble UV filter, or more specialised filters designed to
create or enhance certain effects.
It surprises me though how many people are
not sure about what filters do, or even how to use them properly.
So, here is a run down on what I believe to
be the most important filters we should be considering. I’m
going to leave specialist types like soft focus out - they’re
more the trade of playboy photographers (unless of course
you consider your fishing or hunting mate could benefit from
a smoothing of wrinkles and blemishes?). I’m going to
focus on filters for colour photography; filters for black
and white photos are a completely different kettle of proverbials
getting into the specifics, the most important advice I can
give is that your filter use should not be obviously noticeable.
As soon as a filter gives itself away to the viewer we’ve
lost the point of using it I believe. Subtlety is the key.
I’ll be talking about two differently
constructed types of filters. The first and by far the most
common is the circular screw on type. This is a glass filter
that screws onto the front of your lens for a desired effect.
The other is the 'Cokin' type which is a square, or rectangular,
piece of plastic that slots into a filter holder on the front
of your camera.
Firstly, it’s a good enough reason to
carry camera filters in the outdoors, if for no other reason
than as emergency sunglasses. I know of at least one chap
who been able to tape polarising filters across his eyes as
temporary protection from snow blindness! Here goes....
Monkey Puzzle Gorge, South Westland. I wanted to create a
depth to this photo - the river winding through the image.
Although it was an overcast day, the use of the polarising
filter lifted the sheen from the surface of the river, exposing
the beautiful texture below. The filter has also removed much
shine from the surrounding foliage, allowing the camera to
capture their true underlying colours and get maximum colour
saturation. Bronica ETRSi 6x4.5, 40mm
lens with polarising filter. Fujichrome RDP100.
or UV, filters
Well, if you own a camera chances are that you own a skylight,
or UV, filter. Do you know why? More than likely the salesman
sold you one when you brought the camera because “ you
needed one”. What does it do? Well in my mind, it’s
worth is not in the photographic benefit you’ll derive
from it, but solely from the insurance benefit. Smack your
lens on a rock (not an unlikely thing in the hills believe
me) and a $20 piece of metal and glass martyrs itself for
your prized camera lens. It also unselfishly takes a heap
of abrasive ‘cleaning’ that would render your
expensive lens front as useless as a really useless thing
if you insisted on scrubbing away with toilet paper to dry
a lens as some folk do.
Their real use is attempting to reduce any
haze that strong scattering of UV light may cause. The skylight
filter is essentially a UV filter with a slight pink tinge
in the glass. The idea here is to neutralise the slight cold
cast that UV light may produce in your images. So the message
here is to keep a piece of glass between your delicate bits
and anything that could be out to damage them - a cheap and
relatively important piece of gear.
Moving right along to a more functional piece of equipment,
the polarising filter is an absolute must for the outdoors
photographer, simple as that.
I’ve listened to salesmen in shops explaining
that you need one of these to get a really blue sky in your
photos. They’re right on that count, but there are a
heck of a lot more benefits (and pitfalls) to this filter
that you need to know about. Lets understand it’s operation
Basically, on a fine day all light is traveling
down from a single light source, the sun. When it hits objects
it is reflected and scattered in many directions. When this
happens, light may become polarised differently to that arriving
from the sun. I won’t bore you with heavy physics explanations
here, but simply explain it by saying that light waves may
vibrate at one angle and when they’re been polarised
they will vibrate at a different angle. The beauty of a polarising
filter is that it can filter out light that is polarised at
a given angle, by rotating the filter. This gives us the ability
to control problem light, such as that reflecting upwards
off water, exactly the same job a pair of fishermans’
polarising glasses does, allowing him to see through any reflections
on the waters surface.
Hunters returning to bivvy
camp above the Oroua River, Ruahine Forest Park. Here a
polarising filter was used to deepened the blue of the sky,
and whitened the clouds. Maximum effect was achieved because
the image was taken at right angles to the sun (south).
Olympus OM4Ti, 24mm zuiko lens with polarising filter. Fujichrome
polarising filter looks like ‘black’, or dark,
glass and is labeled PL or C-PL. It is different to all other
filters because it is designed to be rotated once it is on
the camera lens; it is also relatively more expensive than
others. The main use that people put this filter to is to
produce beautiful deep blue skies and enhance the appearance
of cloud in the sky. This happens largely because of the increased
contrast range because of the deeper blue. For this they are
superb and almost mandatory I think, especially in the high
The use of a polarising lens is simple, screw
it onto the front of your lens, compose your shot and then
rotate the filter until you get the desired effect you’re
after - deep blue sky and pure white clouds (note that some
lenses rotate the filter when they focus and this might adjust
the filter from how you set it), and take your shot. All this
is simple, but it relies on a couple of bits of important
Firstly, the polarising filter is a very good
light robber, it will reduce the amount of light entering
your camera by 2 stops, i.e. it will only allow a quarter
of the available light through. Fortunately this is not generally
a problem on a bright sunny day, but bear it in mind. Note
that if your camera (as most modern cameras do), meters through
the lens then you don’t have to worry about exposure
details. If you use a lightmeter though you’ll have
to deduct the 2 stops of light from your reading. The second
important piece on info relates to the effectiveness of the
filter. If you are facing towards, or away, from the sun then
the filter will have minimal effect. If you are facing at
right angles to the sun you will get maximum effect (the deepest
blue sky etc.).
Besides creating a beautiful deep blue sky,
you will find if you play around with this filter that tree
foliage will go a magnificent deep green colour, especially
at right angles to the sun. You often see luscious deep green
forest photos and wonder why you can’t get them like
that? Well, the polarising filter may help you. In the same
way that this filter will take glare off the surface of water,
it will take the glare off plant leaves. The result is often
a huge increase in the colour saturation of the photo. Classic
foliage for this is silver, black and mountain beech trees
as they have very small shiny leaves. Get right angles to
the sun and turn your polariser and watch then change from
a silvery green to a deep lush, almost edible, green. In general,
the polariser will increase the colour saturation of your
photos. Along with this though is an increase in contrast
and you will lose a bit of detail in any shady parts of the
Most people use their 'pola' filter only on
fine days. Few know it’s benefit on overcast days. If
used it will greatly increase your colour saturation, however,
you’re probably going to need a tripod as there is a
lot less light about on these days, and remember it’s
a great light robber. Pola filters are very helpful if you’re
wanting to photograph with a slow shutter speed on a bright
day, say water movement. Use them as a neutral density type
filter, as they will cut down two stops of light and allow
you to use a shutter speed 2 stops slower.
are actually two types of polarising filters, Linear (PL)
and Circular (C-PL) polarisers. Basically, the type of camera
you use dictates which you need because the linear type (although
cheaper) can confuse the autofocus and exposure sensors in
modern auto everything cameras. The circular type can be used
on any type of camera but is a bit more expensive.
Price depends heavily on the size, make and
type (PL, or C-PL). You’d expect to pay around NZ$30-40
for a 49mm PL filter, and around $50-70 for a 58mm C-PL. I
highly recommend that if you’re on a tight budget to
cast around for second-hand filters. You can normally pick
up very good condition (unscratched) filters for about 1/4
of retail price. Some camera shops have boxes fill of them
- ask for a sift through.
The light we see has a temperature to it. Instinctively you
know what I mean - light from the setting sun has more of
a yellowy tinge than the harsh cool sun late in the morning;
the evening sun is warmer. Likewise, bright halogen car headlights
seem a lot more bluey-white (colder) than say the light of
a candle (warmer). I remember a very effective TV advert selling
home insulation, Pink Batts I think. Side by side sat the
Pink Batts house and the other non-insulated house. The main
visual difference was that the warm house was painted a slight
pink colour and had a cosy yellowy light bulb hanging in the
window. The cold house was painted a soft blue and had a stark
bluey-white light hanging in the window. Boy, it was so effective
that looking at the cold house gave you the shivers! The purpose
of a warm up filter is to help achieve the same thing as the
Pink Batts advert, to give your images a warm alluring feeling
(if that’s what you’re after). It is designed
to subtlely shift the colours in your photo away from the
colder blues and into the warmer yellowy-browns.
There are two main types of warm up filters.
They’re coded as either 81 or 85 series, and they’re
coded for their strength. 81 series type are amber in colour,
while 85 series type are more pink. My advice would be to
go for the 81 series. The strength of the filter varies with
the letter after it; 81a is the weakest and 81d is the strongest.
Generally I would not be interested in using a warm up filter
stronger than 81b as it starts to look unnatural, however
there is considerable difference in strength between manufacturers.
It is worth experimenting with warm-up filters to find your
preference - some people won’t like any.
Although, if you’ve got a hunting mate
that likes to take their shirt off occasionally, and he or
she has an ‘office’ suntan, then an 81d might
be worth the investment! The result will be white chicken
flesh changed to well grilled with the screw on of a filter!
Price is much more attractive than polarisers, these cost
around $25 for a medium sized one.
Pancake Rocks, Paparoa
National Park. Here the use of a graduated grey filter has
allowed me to darken the clouds into a very foreboding sky.
The light grey sky was very much brighter than the rest of
the scene and would have been captured as an overexposed white
space. Now it’s tone is similar to the rest of the image,
and the detail in the cloud is visible. Bronica
ETRSi 6x4.5, 40mm lens with grey grad. filter. Fujichrome
Grad, or Graduated Neutral Density filter
This is a very useful filter, but the draw back is that it
takes some effort to use in the field; it’s fiddly and
easy to muck up. Here’s the theory...
When we’re photographing a landscape
photo, we’ve often got a big contrast in brightness
between the land and the sky. Normally the sky is much brighter,
especially if it’s an overcast day (because the sky
will be a bright grey colour).
Because photographic film is not as good at
recording the huge range of brightness that our eye can deal
with, some of the photo will inevitably be over or under exposed.
This is where the grey grad. filter is very useful.
Essentially it’s a filter that is clear
at one end and tinted grey at the other, the filter graduates
from no filter, to a dark neutral grey. The idea here is that
we can move the filter up or down in it’s holder so
the tinted portion covers the sky, and the clear bit covers
the landscape. It’s like selective sunglasses. The sky
will now be closer in brightness to the land and your film
will be able to record the scene with ease. Likewise you can
use these filters to dramatically darken the sky, if you’re
after more atmosphere etc. And there is a range of different
coloured tints available for different tasks.
The most common make of these filters in New
Zealand are the Cokin brand. They come in two sizes and are
available in most camera shops. You will need to purchase
a filter holder initially that screws onto the front of your
camera. This opens you to a wide range of special filters
that Cokin are known for.
To use graduated filters takes a little care.
You must remember to take your camera meter reading off the
land before you install the grey grad. That way the land will
expose as required and the filter will not effect the reading.
You must also take care when you have objects such as trees
that extend into the sky (and therefore the darkened part
of the filter) as the filter will make them very dark and
unnatural. They are also excellent at picking up a static
charge and will pick up dust and lint from all over the show,
and you know how much lint you make when you’re in the
hills! Oh, and they scratch very easily! Cost is about $30-35
for the basic size if I remember rightly.
Diopters, or supplementary close
While not strictly filters, these deserve a mention anyway.
As detailed in the Macro (close-up) photography column (Dec’97/Jan’98),
Diopters are a convenient screw on lens for close-up photos,
not just a piece of tinted glass. They normally come in sets
of 3 different powered lenses, +1, +2 and +4 power. These
are very convenient to carry in the outdoors because they’re
lightweight and versatile. You can check it out by
The Four Sentinals,
Wellington South Coast. The winter sky had just cleared after
a horrendous southerly storm in the capital; the swell was
rolling in and the air was clean and crisp. This shot was
MADE by the polarising filter. Without it the sky would have
been an insipid light blue colour and the exploding waves
would have soaked into it.
Olympus OM4Ti, 135mm zuiko lens, polarising
filter. Kodachrome 64
As all camera lenses have different sized front filter treads,
you might have to buy several sizes to cover all your gear
(it does help buying the same brand though). You can however
buy stepping rings which allow you to use larger filters on
smaller lenses. This helps the wallet and also the weight
of your back pack. Likewise, with the filter holder set up,
such as Cokin filters, once you’ve bought the correct
adapter, then the filter holder simply fits all lenses.
If you’re shooting print film, the machine
that prints your photos from the negative can alter the colour
balances. So if you’re using a warm up filter, the machine
may automatically remove the slight amber cast. You should
discuss this with the agent that develops your films. On the
other hand, if you’re shooting slide film you can be
sure that what you get back is exactly what you took.
previously mentioned, many photographic shops have boxes full
of second-hand filters. It is worth your while if you’re
on a tight budget to have a fossick through these.
Well, get snapping, because as they say, the
world looks much better through ‘rose-tinted’
This article and images are
copyright to Rob L. Suisted - Nature's Pic Images. All rights