Canon EOS 30D Instruction Manual page 272

learn more about macro lenses
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CJ""n~I"'\C'!"""'1"'\
or contraction of
What1s
USM?
This stands for Ultrasonic Motor. Canon has pioneered development
of USM for camera lenses.
In
fact, we've optimized autofocus
action for quick, responsive performance with high torque while
minimizing motor noise.
VViihout using USi'v\!inner focusing
UsiilfJ UStv'\/inner focusing
situations.
Convenient for
When you want to photograph a small animal or
an insect, it's important to get close quietly -
without scaring the subject. Canon Macro Lenses
with USM and inner focus let you photograph
subjects with quiet, rapid autofocus. You'll feel
confident to approach many subjects that are
sensitive to sound and motion in the big world
around them. You'll be able to get close and
capture big, bold images of small worlds!
What1s
inner focus?
Technology activates focusing by shifting a group of lenses inside the unit, rather than moving (expanding or contracting) the
whole lens unit. Since the overall length of the lens doesn't change, you can enjoy shooting ease and compact dimensions.
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