Why White Balance is important
If you look at many photos taken indoors you will see that they have a yellow
cast. This is because indoor lights have a DIFFERENT COLOUR TEMPERATURE to
daylight.
White balance may be an odd concept to grasp but it can become intuitive –
and you can achieve quite abstract effects by deliberately choosing a “wrong”
white balance
The White Balance (WB) determines how accurately the colours in photos come
out, specifically, it determines how ‘warm’ or ‘cool’ an image feels.
Setting WB accurately will prevent against nasty colour cast which will make
your images look unnatural. Different colour casts come from white not being
true white in different lighting situations.
Your camera
Modern digital cameras give you the option to change the WB manually as well
as the auto white balance (AWB) option.
AWB is often suitable for daylight situations but, in most other situations, it’s just
guessing as to what the balance should be. The most common example for this
is when shooting indoors in tungsten light.
In a typical digital SLR (and more advanced compacts) you will typically have a
scale of white balance to choose from:
Auto: Good if you don’t know what you’re doing and it works well in sunlight but
in most situations is unsuitable.
Daylight: Auto mode can been good in daylight but not perfect. I would
typically use this balance in daylight but most people tend to stick to auto
because they’re worried about forgetting to change the WB when they go
back indoors.
Shade: Auto mode makes photos look a little cold in the shade so using this
preset will be a lot more accurate.
Cloudy: Again, this is self explanatory as to when you might use it.
Tungsten: This light comes from incandescent bulbs found in the home – left on
auto, photos will come out very warm with an orange/ yellow cast.
Fluorescent: This comes from tube lighting found in offices and hospitals. It’s a
very cold light and can make your photos appear blue. This is also why offices
have that nasty sterile feel.
Flash: This compensates for the somewhat cool light of the camera’s flash.
Custom: This is used for setting the white balance accurately using a grey card
All of these modes simply tell your camera how much it should adjust the colour
of the photo being taken.
Perfect Colour Reproduction
Using grey cards.
Grey cards are used to determine which white balance should be used by your
camera; they are a made from 18% grey which is a neutral hue.
To use grey cards, take a photo of the card so that it fills the whole frame of your
camera, then set this as the white balance inside your camera. The camera
sees the difference between the result and the neutral hue and determines the
balance from that.
The reason a grey card is used over white is because, if you overexpose any
colour enough, it’ll eventually come out as white; WB is about colour, not
brightness. As the grey photo was taken in the same lighting environment as the
rest of your photos will be, the camera knows exactly how much to adjust the
balance.
Custom: This is where you would take the photo of the grey card and set it as
your white balance. All cameras are different so consult your manual as to how
to do this. This is the most accurate way possible to capture colour.
Colour Temperature / Kelvin: This is used by professional photographers who are
used to using expensive colour temperature meters in studio conditions and
setting the WB value manually. The value is set in Kelvin (K)
For example, sunlight is approximately 5200K and tungsten is approximately
3200K.
Using grey cards or temperature meters is generally not worthwhile for most
situations
Which Setting can be used?
There are basically 5 options:
1: Shoot on auto mode and hope for the best. This is fine if you’re still trying to get
to grips with exposure but once you feel confident about this it is better to be
more precise
2: Try to produce accurate results using the preset modes inside of your camera.
This is likely to produce much more accurately.
3: Shoot in RAW. For those of you who are uncertain, RAW is an uncompressed
file format that allows you to change things on a computer after the photo has
been taken. One of these things is the white balance. It is available in all Post
Processing software and allows you to select the light you want.
YOU CAN ALSO –
4: Shoot in custom mode. This is the most popular choice by professional
photographers but takes some time to get used to and requires carrying around
a grey card.
5: Use a light temperature meter. This is very accurate but it is very expensive so is
not a realistic option for most. Nor is worthwhile in most situations
These options are not considered in this section
At its simplest – the reason we adjust white balance is to get the colours in your
images as accurate as possible.
Why would you need to get the colour right in your shots?
You might have noticed when examining shots after taking them that at times
images can come out with an orange, blue, yellow etc look to them – despite
the fact that to the naked eye the scene looked quite normal. The reason for
this is that images with different sources of light have a different ‘colour’ (or
temperature) to them. Fluorescent lighting adds a bluish cast to photos whereas
tungsten (incandescent/bulbs) lights add a yellowish tinge to photos.
The range in different temperatures ranges from the very cool light of blue sky
through to the very warm light of a candle.
We don’t generally notice this difference in temperature because our eyes
adjust automatically for it. So unless the temperature of the light is very extreme
a white sheet of paper will generally look white to us. However a digital camera
doesn’t have the ability to make these adjustments automatically and
sometimes will need us to tell it how to treat different light.
So for cooler (blue or green) light you’ll tell the camera to warm things up and in
warm light you’ll tell it to cool down.
Adjusting White Balance
Different digital cameras have different ways of adjusting white balance so
ultimately you’ll need to consult your camera manual to work out the specifics
of how to make changes. Having said this – many digital cameras have
automatic and semi-automatic modes to help you make the adjustments.
Preset White Balance Settings
Here are some of the basic White Balance settings you’ll find on cameras:
 Auto – this is where the camera makes a best guess on a shot by shot
basis. You’ll find it works in many situations but it’s worth venturing out of it
for trickier lighting.
 Tungsten – this mode is usually symbolized with a little bulb and is for
shooting indoors, especially under tungsten (incandescent) lighting (such
as bulb lighting). It generally cools down the colours in photos.
 Fluorescent – this compensates for the ‘cool’ light of fluorescent light and
will warm up your shots.
 Daylight/Sunny – not all cameras have this setting because it sets things as
fairly ‘normal’ white balance settings.
 Cloudy – this setting generally warms things up a touch more than
‘daylight’ mode.
 Flash – the flash of a camera can be quite a cool light so in Flash WB
mode you’ll find it warms up your shots a touch.
 Shade – the light in shade is generally cooler (bluer) than shooting in
direct sunlight so this mode will warm things up a little.
Manual White Balance Adjustments
In most cases you can get a pretty accurate result using the above preset white
balance modes – but some digital cameras (most DSLRs and higher end point
and shoots) allow for manual white balance adjustments as well.
AN INTRODUCTION TO DEPTH OF FIELD
A basic definition of depth of field is: the zone of sharpness within a photo that
will appear in focus. In every picture there is a certain area of your image in
front of, and behind the subject that will appear in focus.
This zone will vary from photo to photo. Some images may have very small zones
of focus which is called shallow depth of field. Others may have a very large
zone of focus which is called deep depth of field.
The Three main factors that will affect how you control the depth of field of your
images are:
 aperture (f-stop)
 distance from the subject to the camera
 the focal length of the lens on your camera.
How does aperture control depth of field?
Aperture refers to amount of light from the lens to the camera sensors. The size of
your aperture (the diameter of the hole through which light enters the camera)
controls the amount of light entering your lens.
Using the aperture (f-stop) of your lens is the simplest way to control your depth
of field as you set up your shot.
A general rule to follow is:
Large aperture = Small f-number = Shallow (small) depth of field eg f2
Small aperture = Larger f-number = Deeper (larger) depth of field eg f22
It may be easier to remember this simple concept: The lower your f-number, the
smaller your depth of field. Likewise, the higher your f-number, the larger your
depth of field. For example, using a setting of f/2.8 will produce a very shallow
depth of field while f/11 will produce a deeper DoF.
How does distance control depth of field?
The closer your subject is to the camera, the shallower your depth of field
becomes. Therefore, moving further away from your subject will deepen your
depth of field. And remember that this means MACRO shots will always have a
very shallow depth of field
How does the focal length of a lens control depth of field?
Focal Length refers to the capability of a lens to magnify the image of a distant
subject. This means that that the longer you set your focal length the shallower
the depth of field.
Using POINT and SHOOT cameras
Even with a point and shoot camera, there are ways to control your depth of
field.
In the Scene Modes menu, look for a symbol of a human head, which is the
setting for portraits. This will give you a narrow depth of field.
In the same menu there is also a mountain symbol, which is a setting for
landscapes, which will give you a deeper depth of field.
This tells you that deep depth of field is generally appropriate for landscapes
and that a shallow depth of field is used to separate subject from the
backgound.
If you are a beginner with a DSLR there are some simple ways you can control
depth of field and still use an automatic shooting mode. By choosing Aperture
Priority mode you can set your aperture to get the depth of field that you want,
and the camera will automatically set the shutter speed.
Can I set the depth of field exactly for each situation?
Yes, but because changing your aperture affects your shutter speed, the result
may not meet the needs of your image.
For instance, if you are trying to increase your depth of field by reducing
aperture size you will also need to increase (slow down) your shutter speed
which could make your image blurry. Understanding how all these settings work
together can increase your control over depth of field.
The image below illustrates the relationships involved
Is depth of field equally distributed in front and beyond the focus point?
No, it’s usually about one third in front and two thirds behind your focal point, but
as focal length increases it becomes more equal.
Does understanding depth of field improve my images?
Managing depth of field is one of the most important tools in photography,
because having sharp images is one of the most important factors to getting a
good shot. Knowing how to make the parts of your image you want sharp and
the parts you want to be out of focus, is an artistic tool to create the best
images you can.
When is shallow depth of field the best artistic solution?
Using a shallow depth of field is a good way to make your subject stand out
from its background and is great for portrait photography. Shallow DoF can also
be useful in nature photography, where you want the subject to stand out from
its surroundings. Think of how you would want to see a single flower bloom. This is
also useful because many wildlife photo opportunities are low light situations,
and increasing your aperture size will give you more light.
Shallow depth of field may also be effective for sports photography where many
times you want to separate the athlete from the background to bring attention
to them. The result of this should also help give you a fast enough shutter speed
to help freeze the action
When is deeper depth of field the best artistic solution?
In landscape photography it is important to get as much of your scene in focus
as possible. By using a wide angle lens and a small aperture you will maximize
your depth of field to get your scene in focus.
Determining depth of field?
There are several on-line sites that will provide depth of field charts for your
camera and lenses.
Also, there are a number of apps available for smart phone users that can
calculate it .
Most cameras have a DoF preview button which will give you a preview as you
look through the eye piece. (This is probably the easiest and most under-utilized
method.) Using this button may cause your image to appear darker as you view
it through the eye piece. Your image will still be properly exposed as long as you
have the correct exposure settings.
Can everything be in focus?
Yes, using the hyperfocal distance. When you are focused at the hyperfocal
distance, your depth of field will extend from half the distance to your focal point
to infinity. You can use a DOF calculator to find your hyperfocal distance.
However, a good rule of thumb is to focus a third of the way into the scene.
Using an aperture of about f/11 or higher with a wide angle lens will maximize
your depth of field.
Depth of field in macro photography?
Because most macro images are produced in low light and with a longer focal
length, the depth of field is often very shallow.
Adjust your lens to the smallest aperture that the light will allow. It may also be
necessary to increase your ISO to allow you to properly expose the image and
to maximize your depth of field.
In many macro images your DoF may be miniscule. With this very narrow focus it
becomes necessary to use a tripod, because even the slightest movement of
the camera will move your macro subject outside your depth of field.
To summarize controlling depth of field:
Increase depth of field
 Narrow your aperture (larger f-number)
 Move farther from the subject
 Shorten focal length
Decrease depth of field
 Widen your aperture (smaller f-number)
 Move closer to the subject
 Lengthen your focal length