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Canon cameras provide a number of options for image type from RAW,
with the most data and fl exibility of all fi le types that the camera’s sensor
can provide, to Large (L), Medium (M), and Small (S) jpegs. Each fi le
size will provide high quality images. The diff erence is in the degree of
enlargement a given fi le will withstand before artifacts and pixelization
become noticeable.
Large jpegs deliver a full size fi le, so if you have a 10 megapixel sensor
you will see a 30 mb fi le (10 mb for each channel of red, green, and blue)
when it’s opened in software like Photoshop.
Medium jpegs will produce fi les about one-half the size, or about 15 mb
for a 10 megapixel sensor. Basically, the camera ignores about half the
data. This reduction in resolution will not be noticeable if the print size
does not exceed the capabilities of the fi le.
Small jpegs will be roughly one-fourth the size of a full fi le, in this case
about 7.5 mb. While you have less opportunity for enlargement, the
lower resolution of the fi le will not be appreciably noticed as long as you
understand, and work within, its limitations.
Based on the job at hand, it will be up to you to determine the most
effi cient resolution choice for your work. High-ticket jobs like commercial,
advertising, portraiture, or weddings will generally demand RAW or Large
jpeg fi les. Depending on your camera’s sensor size and resolution, images
meant for snapshot prints, even 5 7s, will look great when shot as
Medium jpegs; Small is fi ne for web use, possibly even for 3 5s or 4 6s.
Canon cameras off er the opportunity to shoot both RAW and jpeg fi les at
the same time. All models allow at least RAW Large (aka High) jpeg and
RAW Small jpeg. Newer models also provide RAW Medium as well
as slightly more compressed versions of Large and Small jpegs. With the
addition of the new, 2.5 megapixel Small RAW (sRAW) fi le available on the
Mark III, the total number of quality options is a staggering 14 diff erent
ways to save your fi les (FIG 4.9).
Auto Exposure Bracketing
If you primarily work in jpeg, Auto Exposure Bracketing (AEB) is a great
little tool, easy to implement, that will help you get even more out of your
images. There are many instances in a photographer’s career when “just
a little more” or “just a little less” would have made the diff erence
between a great image and an outstanding one, but there was no
opportunity to download to a calibrated computer to judge the fi nal
image. And, although one could certainly shoot RAW and adjust an image
in manipulation software later, that does require more work. Even though
it might take only a few minutes, time is money.
When you engage this feature, the camera will set itself to shoot a
bracketed series of three exposures, in one-third stop increments, up to
three full f-stops under and over the target exposure. This feature works
in every Creative Zone mode except Bulb and is perfect for adding a bit of
subtlety to your work.
With EOS-1 bodies, push the Mode and AF buttons at the same time. The
top LCD panel will change from its usual inclusive display to a minimalist
view showing only Exposure Compensation, 0.0, and an icon that
represents a bracketed exposure
Use the Quick Control Dial to select the amount of diff erence between
exposures.
The AEB feature is just as easy to use with prosumer EOS bodies. Just fi nd
the item in the Menu, select it, and use the Quick Control Dial to set the
amount of exposure bracket you wish. Push the shutter three times to
record the exposure bracket.
Once your picture is composed, click the shutter three times. The fi rst
exposure will be what you’ve determined to be “on the mark,” the next
will be the underexposed frame, followed by the frame that’s brighter
than the mark Most cameras will allow as many additional series as you wish, and AEB
will remain active until you either dial the exposure spread back to zero
or turn the machine off . You can change the sequence of shots and
whether or not AEB stays active after a series by engaging a Custom
Function. Refer to your manual to determine which Custom Function
allows this on your camera.
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