Essential Filters for Contrast Control in Digital

Essential Filters for Contrast Control in Digital Nature Photography
By Darwin Wiggett
Many photographers think that filters are for special effects like adding a tobacco-coloured sky to a
daylight scene or adding a starburst effect to sparkling highlights. But there two types of filters that are
essential to outdoor and nature photography and these are filters which help us control contrast in a
scene. In nature often the contrast range of a scene is beyond what can be recorded successfully on the
sensor. The range of brightness between shadows and highlights is usually so extreme that neither is
recorded with detail on the sensor. There are several options available to photographers to help reduce
the contrast range of light in the scene. The first is to return to the scene when the light is lower in
contrast like you get on a cloudy day (but that changes the character of the light). The second is to add
light to the shadow areas using fill flash or a reflector but this solution is not too practical with grand
scenics. The third solution is to make numerous exposures to record detail in shadow, highlight and midtone areas and then blend these exposures together in post-processing. This latter practice often works
well but is time-intensive. The last option is to use contrast control filters like a polarizer and neutraldensity graduated filters (grads for short) to get the exposure correct in-camera. When possible I prefer
this last method because it gives me high quality in-camera captures and requires little post-processing
effort giving me more time in the field to take photos. Let’s take a look at how polarizers and grads help
tame the contrast in landscape and nature photography.
The Polarizer for Global Contrast Control
One of the easiest ways to make better nature photos is to use a polarizer. The effect of a polarizer can’t
be duplicated in software – period. A polarizer removes reflective highlights (glare) reducing contrast
and enriching colours. In short, a polarizer usually gives you much more pleasing images than photos
recorded without the filter. I almost always have a polarizer on my lens when doing outdoor
photography. To really understand when and how to use a polarizer refer to my article “Seven Rules for
Effectively Using a Polarizer”. Below is a comparison of the same photo shot without (photo 1a) and
with (photo 1a) a polarizer. It is easy to see how contrast is reduced and colours are enhanced with a
polarizer. In photo 1b I used a Singh-Ray warming polarizer which not only gave me reduced contrast
and snappier colours, it added extra warmth to the scene with its built in warming filter. I can’t imagine
photographing landscapes without using a polarizer.
Photo 1a – no filters.
Photo 1b – Singh-Ray LB warming polarizer used to reduce reflective glare, saturate colours and warm
up the scene.
What Kind of Polarizer?
If you are convinced that a polarizer is in your future, then you’ll need to decide which kind of polarizer
to get. I like Singh-Ray’s LB Warming Polarizer for two reasons; first, the polarizer only sucks up one-stop
of light rather than 2-stops which is typical of other manufacturer’s polarizers. Getting a little extra
shutter speed is important if you photograph active subjects like wildlife or sports but want the benefit
of a polarizer. Secondly, I like the lovely warm cast that is imparted with the LB Warming polarizer. If you
want no additional colour cast to your photo, then buy Singh-Ray’s LB Neutral Polarizer.
Once you decide which polarizer to buy you need to decide if you will buy a screw in polarizer that
attaches to the threads on the front of you lens, or if you are going to go with a filter holder system and
buy a drop-in polarizer. I discuss these options in detail in Filters, holders and vignetting: building a filter
system that works with your lenses. Personally, I like to use a filter holder system on each of my lenses
so I can easily transfer my polarizer from lens to lens and so I can add additional filters like grad filters in
front of my polarizer for even more refined contrast control. In Photo 2, I show a Cokin P-holder that I
use on my cameras to simultaneously hold a drop-in polarizer and a grad filter.
Photo 2 – A Cokin P-holder with a drop-in polarizer and a grad filter
Grad Filters for Local Contrast Control
In landscape photography often skies are much brighter than foregrounds and if you properly expose for
the foreground, then the sky washes out. In photo 3, the top image was shot without a grad filter and
the bright sky lost all detail. In the bottom image in photo 3, I used a 3-stop hard-edge grad filter to
darken the sky to properly retain exposure. A grad filter is most often used to even out the exposure
between the bright sky and the darker landscape.
Photo 3 – top image no grad filter, bottom image grad filter over sky.
What Grad Filters Do I need?
Grad filters come in different strengths and types. Photo 4 shows the various kinds of grad filters.
Starting at the top is a Singh-Ray P-size (84x120mm) Hard-Edge grad filter. The right filter is a larger
Singh-Ray 4x6 inch size (100x150mm) grad that has a soft-edged transition. At the bottom is a P-sized
soft-edge grad and to the left is a specialized P-sized Reverse grad filter. Each grad filter type comes in
various strengths from 1-stop to 5-stops of density. The difficulty for beginners is deciding which type of
grad filter (hard-edge, soft-edge or reverse) and which strength of grad is most useful. After using grad
for over 20 years, I have found that just 3 grads cover over 80% of my needs
Photo 4
The 3-Stop Soft-Edge Grad for Reflections
I use a soft-edge grad mostly for images of lake reflections where I have a foreground that is in the
shade and I want to show detail across the frame. For example in Photo 5a, I wanted to photograph a
sunrise sky reflection but have detail in the rocky shoreline and in the canoe. Without a grad, the sky
becomes a pale wash. A 3-stop soft-edge had enough density in the upper part of the filter to hold back
the bright sky. The transition or ‘soft-edge’ slightly darkened the reflection and the clear part of the filter
kept the foreground bright (Photo 5b). Photo 5c shows the end result--a perfectly exposed image using
the 3-stop soft-edge grad.
Photo 5a – Reflection shot without filters
Photo 5b – using a 3-stop soft-edge grad to even out exposures in reflection shots.
Photo 5c – the in-camera capture using a 3-stop soft-edge grad filter
The comparison in photo 6 shows a mountain reflection shot without any filters (left) and then with the
3-stop soft-edge grad (right). The right image has a beautiful realistic tonality that was easily captured in
camera just by using the grad filter.
Photo 6 – left image shot without a grad filter, right image shot with a 3-stop soft-edge grad.
The 2 and 3-stop Hard-Edge Grads for Defined Horizons or Defined Lines of Shadow and Light
I use hard-edge grads whenever I have a well delineated horizon line like on the prairie, desert or ocean.
I also use a hard-edge grad whenever I see that the line of shadow and light is well defined. The density
of the grad I use (2 or 3-stops) simply depends on how bright the differences are between the shadow
and light. Let’s take a look at a couple of examples.
In photo 7 when I properly exposed for the foreground rocks, the dramatic but brighter sky washed out
(left image). Because the horizon line is well defined a hard-edge grad worked perfectly well here to
hold back the bright sky. In this case I used a 2-stop hard-edge grad to even out the exposure (right
image). Be careful not to use too strong of a grad filter or else your skies will look overly dark and the
image will look ‘off’. Often I will start with the 3-stop hard-edge grad first, look at the image on my
camera’s LCD and then decide if the grad was too strong. If it is I will then try my 2-stop grad for a less
intense effect.
Photo 7 - left image shot with no filters, right image shot with a Singh-Ray 2-stop hard-edge grad
In photo 8, the horizon is punctuated by the peaks of mountains and so the horizon is not even.
Nevertheless, the light on the mountain peaks is well defined and mostly forms a straight line which
allows use of a hard edge grad filter. The photo without the filter can be seen on the left, while the right
side shows the effect with a 3-stop hard-edge grad brought over the lit part of the scene. To precisely
place the grad so the hard-edge of the grad filter lines up perfectly with the line of light, I use my
camera’s depth-of-field preview button to see the effect of aperture on definition of the grad line. For
more information about how aperture choice affects the edge transition of grad filters go to this link.
As a side note I also used another filter in the image on the right which is not a contrast control filter but
is a special effects filter. I used a Singh-Ray 5-stop solid neutral density filter to increase exposure time
so that the moving water in the scene recorded in a more ‘mystical’ manner. To read more about how I
use the 5-stop solid ND filter for creative effects see my article The Terrific Triple Threat.
Photo 8 – left, no filter; right Singh-Ray 3-stop hard-edge grad and 5-stop solid ND filter
Often when I shoot at sunrise or sunset directly into the sun, a 3-stop hard-edge grad is not strong
enough to hold back the bright sky. In these situations I will use both the 2 and 3-stop hard-edge grads
together to give me a density of 5-stops to hold back the bright sky. Often this one-two punch is enough
to tame the contrast (see photo 9).
Photo 9 – Shot with Singh-Ray 2 and 3-stop hard-edge grads stacked over the sky
Polarizers and Grads Together for the Ultimate in Contrast Control
It is pretty easy to see the differences that filters can make in controlling nature’s contrasty light.
Polarizers are great for taming reflective highlights while grads are often used to dim down the
brightness of sunlit areas or bright skies. Combine a polarizer and a grad and you can really begin to
deliver a beautiful image that your camera’s sensor will love. In Photo 10a, the contrast was just too
much for the sensor to record detail across the scene.
Photo 10a – no filters
To help remedy the high contrast in this scene, the first filter I grabbed was my Singh-Ray LB warming
polarizer. The polarizer removed reflective glare from the water and the algae giving richer colours. The
warming filter also helped remove the blue cast in the shadows. You can see the effects of the polarizer
in photo 10b.
Photo 10b – shot with a Singh-Ray LB warming polarizer
In photo 10c, I used a Singh-Ray 3-stop soft-edge grad because this is a reflection shot where I want the
most density over the sky, a little density over the reflection and no density over the foreground. The 3stop soft-edge grad gave me the additional contrast control I needed to tame the light in this scene.
Photo 10c – shot with a Singh-Ray LB warming polarizer and a Singh-Ray 3-stop soft-edge grad filter.
My Essential Contrast Control Filter Kit
Whenever I go out into nature to make images, I always have my four essential contrast control filters.
My Singh-Ray LB warming polarizer helps me tame reflective glare and enhance colours and my three
Singh-Ray grads (2 and 3-stop hard-edge and 3-stop soft-edge) help me tame uneven light. With these
filters, I can successfully photograph almost any scene. If you prefer to get the best possible captures incamera and wish to spend less time in post-production, then these four filters are the ticket.
Website – www.darwinwiggett.com
Blog - darwinwiggett.wordpress.com
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