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Canon’s EF300mm f/2.8L IS II USM and EF400mm f/2.8L IS II USM are
OO“IS” stands for Image Stabilizer. OO “USM” stands for Ultrasonic Motor.
Features
1.The Image Stabilizer gives the equivalent effect of a shutter speed four stops* faster.
Also, a third Image Stabilizer mode effective for shooting irregularly moving subjects.
2.Use of fluorite lens elements giving superior
definition.
3. SWC (Subwavelength Structure oating) reduces flare and ghosting.
4.Using a fluorine coating on the foremost and rearmost lens surfaces allows adhered dirt to be removed more easily than before.
5.Ultrasonic motor (USM) for fast, quiet autofocus.
6.Manual focusing is available after the subject comes into focus in autofocus mode (ONE SHOT AF).
7.An AF stop button to pause autofocus whenever desired.
8.A power focus mode enables smooth focus change.
9.A focus preset function for advance storage of focusing positions in memory to allow instantaneous focusing.
10.Circular aperture for producing beautiful softfocus images.
11.Can be used with EF1.4× III/EF2× III extenders.
12.Attachment slot provided for
13.Tight seal structure ensures excellent dustproof and
14.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.