From the Rebel to the Mark III, all Canons have a menu of preset white
balances. Meant to be used “on the fl y” when walking into a scene or
under rapidly changing conditions (such as dark clouds moving across
sunny blue skies), they are based on predetermined color temperature
numbers and will, in a general way, neutralize colors found in the
situations they were built for.
Canon has placed eight of these white balance presets into each of its
cameras. Let’s see how each will interpret the white balance of a typical
daylight scene.
AWB (Auto White Balance) will look at any scene as it’s being shot and
attempt to neutralize the color it sees from 3000–7000 K. It’s largely
successful, but can be skewed (see Custom White Balance below).
Daylight uses Canon’s default color temperature of 5200 K; Shade works
at 7000 K; Cloudy at 6000 K; Tungsten at 3200 K; White Fluorescent is set
to 4000 K (there are huge color temperature variations in fl uorescent
lights); Flash at 6000 K; and Custom White Balance, which can neutralize
light with a color temperature anywhere between 2000 and 10,000 K.
Custom White Balance
One of the most valuable of all the Menu items, using Custom White
Balance (Custom WB or CWB) will permit you to neutralize whatever light
you’re working under, changing the colors of that light, whatever they
may have been, to clean, non-biased colors.
Light is not a constant color, except to our eyes and brain. Humans have
the cerebral ability to white balance on the fl y, interpreting whatever
color we see to be neutral, based on our ability to see something we
know to be a certain color (white, for instance) and balancing all other
colors against that reference. The CWB function of the camera does
exactly the same thing, except that the camera can leave us with
a physical record, a print, of a situation that has been neutrally balanced.
There are a number of generic white balance settings already in play
on every Canon DSLR (explained elsewhere), but they are not nearly as
precise as a measured, custom, white balance.
To do this eff ectively you will need to meter and photograph a neutral
gray or white card under the light conditions within the frame. If you’re working under studio strobes, you will need to use a calibrated fl ash
meter to accurately measure the strength of the light. Either way, it’s
important to purchase a neutral target. Typewriter paper, tablecloths,
bridal gowns, or other objects contain chemicals or bluing agents that
make them look neutral, but they will not white balance properly because
of that chemistry. A commercially available 18% gray target will produce
the most accurate white balance.
Check your instruction manual to know how much of the frame you will
have to fi ll to get a correct measurement. I think you should err on the side of caution and fi ll as much of the frame as you can. It’s not necessary
for the image to be in focus, although a target like this BalanceSmarter
(www.BalanceSmarter.com) with its printed lines, is helpful because you
won’t have to disable AF to make the shot (FIG 4.26).
In the Shooting menu choose Custom WB (FIG 4.27).
You will be asked to select an image, but the camera always defaults
selection to the last image made. If you’re happy with that image, press
Select (or Set, depending on your model) (FIG 4.28).
On current EOS bodies, if your White Balance icon is not set to Custom,
you will be told to set it accordingly. Push the WB/AF button and scroll to
the CWB icon. Custom White Balance has been set.
EOS-1 bodies will ask you if you want to “Use this white tone?”
Use the Select button and the Quick Control Dial to choose “OK” (FIG 4.29).
Push the WB (White Balance) button and use the Quick Control Dial to
select the CWB icon
|
|
|
