Canon EF 400mm f/2.8L IS USM Manuale Utente (en)

Thank you for purchasing a Canon product.
Canon’s EF300mm f/2.8L IS USM, EF400mm f/2.8L
IS USM, EF500mm f/4L IS USM and EF600mm
f/4L IS USM are high-performance super-telephoto
lenses, for use with EOS cameras. 
“IS” stands for Image Stabilizer.
“USM” stands for Ultrasonic Motor.
Handling Cautions
If the lens is taken from a cold environment into a
warm one, condensation may develop on the lens
surface and internal parts. 
To prevent condensation
in this case, first put the lens into an airtight plastic bag
before taking it from a cold to warm environment. Then
take out the lens after it has warmed gradually. Do the
same when taking the lens from a warm environment
into a cold one.
Do not stand on top of the lens case. You may fall and
injure yourself. 
Do not pile lens cases on top of one another as they
may fall and cause injury.
Do not leave the lens in excessive heat such as in a
car in direct sunlight. High temperatures can cause
the lens to malfunction.
1. The Image Stabilizer gives the equivalent effect
of a shutter speed two stops* faster.
2. Use of fluorite and UD lens elements giving
superior definition.
3. Ultrasonic motor (USM) for fast, quiet autofocus.
4. Manual focusing is available after the subject
comes into focus in autofocus mode (ONE SHOT
5. An AF stop button to pause autofocus whenever
6. Can be used with EF1.4
× II/EF2× II extenders.
7. A focus preset function for advance storage of
focusing positions in memory to allow
instantaneous focusing.
8. Tight seal structure ensures excellent dustproof
and drip-proof performance.
9. Designed for lighter weight with parts made of
magnesium alloy.
* Based on [1/focal length] second. 
Generally, it requires a shutter speed [1/focal length]
second or faster to prevent camera shake.
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