CANON INC. 2010
Extender EF1.4X III/ EF2X III
q Lens mount index (on lens)
w Lens mount index (on camera)
e Lens release lever
t Rubber ring
❇: Using an Extender with this lens may result in incorrect autofocus.
If your camera has an AF microadjustment function, do the AF microadjustment.
If your camera does not have an AF microadjustment function, focus
manually if the AF precision is way off.
* For details on AF microadjustments, see the camera's instruction manual.
* Refer to the camera and lens instruction booklets to see if there are any AF
* The maximum aperture is indicated in half-stop increments.
Thank you for purchasing a Canon product.
The high-performance Canon Extender EF1.4X III and Extender EF2X III increase
the focal length of the attached EF lens by 1.4X and 2X respectively.
• Do not look at the sun or a bright light source through the lens with the
extender attached, or with a camera with the extender and lens
attached. Doing so could result in visual impairment. In particular, never
look at the sun directly through the lens with the extender attached, because
that could result in loss of vision.
• Do not leave the lens with the extender attached, or a camera with the
extender and lens attached in the sun without the lens cap on. That may
result in concentrating the sun's rays, causing a fire.
• Do not leave the extender in excessive heat such as in a car in direct
sunlight. High temperatures can cause the extender to malfunction.
This device complies with Part 15 of the FCC Rules. Operation is subject to the following two conditions: (1)
This device may not cause harmful interference, and (2) this device must accept any interference received,
including interference that may cause undesired operation.
Do not make any changes or modifications to the equipment unless otherwise specified in the instructions.
If such changes or modifications should be made, you could be required to stop operation of the equipment.
This equipment has been tested and found to comply with the limits for a class B digital device, pursuant to
part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful
interference in a residential installation. This equipment generates, uses and can radiate radio frequency
energy and, if not installed and used in accordance with the instructions, may cause harmful interference to
However, there is no guarantee that interference will not occur in a particular installation. If this equipment
does cause harmful interference to radio or television reception, which can be determined by turning the
equipment off and on, the user is encouraged to try to correct the interference by one or more of the
• Reorient or relocate the receiving antenna.
• Increase the separation between the equipment and receiver.
• Consult the dealer or an experienced radio/TV technician for help.
This Class B digital apparatus complies with Canadian ICES-003.
Mounting and dismounting the Extender
First attach the Extender to the lens, then attach it to the camera. To detach it,
follow the same procedure in reverse.
To detach the Extender from the lens, slide the lens release lever as shown by
the arrow, then turn the Extender counterclockwise.
Focal Length & Maximum Aperture
EF135mm f/2L USM
EF180mm f/3.5L Macro USM
EF200mm f/2.8L USM
EF200mm f/2.8L II USM
EF200mm f/1.8L USM ❇
EF200mm f/2L IS USM
EF300mm f/4L USM
EF300mm f/4L IS USM
EF300mm f/2.8L USM ❇
EF300mm f/2.8L IS USM
EF400mm f/5.6L USM
EF400mm f/4 DO IS USM
EF400mm f/2.8L USM ❇
EF400mm f/2.8L II USM ❇
EF400mm f/2.8L IS USM
EF500mm f/4.5L USM ❇
EF500mm f/4L IS USM
EF600mm f/4L USM ❇
EF600mm f/4L IS USM
EF800mm f/5.6L IS USM
EF100-400mm f/4.5-5.6L IS USM
EF70-200mm f/4L USM
EF70-200mm f/4L IS USM
EF70-200mm f/2.8L USM
EF70-200mm f/2.8L IS USM
EF70-200mm f/2.8L IS II USM
EF300mm f/2.8L IS II USM
EF400mm f/2.8L IS II USM
EF500mm f/4L IS II USM
EF600mm f/4L IS II USM
EF1200mm f/5.6L USM ❇
Maximum Aperture with the Extender
When Extender EF1.4X III is attached, the lens maximum aperture will be smaller
(darker) by 1 stop. With Extender EF2X III, the maximum aperture will be smaller
by 2 stops. In any case, the camera will compensate the exposure automatically.
• Do not attach two or more Extenders on the same camera. Doing so will
degrade the optical performance and the camera will not be able to obtain
proper exposure readings.
To enhance water and dust resistance, the Extender EF1.4X III and EF2X III have
a rubber ring around the mount. As the lens is repeatedly mounted and detached,
the rubber ring will leave fine abrasion marks on the outside of the camera mount.
This will not affect operation.
The rubber ring can be replaced by a Canon service center (a fee will be charged).
• Autofocusing slows down when the lens is used with an extender, in order to
maintain the precision of autofocus control.
The Extenders cannot be used with film cameras other than the EOS-1V. Using
an Extender with a film camera other than the EOS-1V may cause misoperation.
Mount: Canon EF mount (Electronically controlled)
Lens construction: EF1.4X III: 7 elements in 3 groups
EF2X III: 9 elements in 5 groups
(Max. dia. × length): EF1.4X III: 72.0 dia. × 27.2 mm / 2.8 × 1.1 inch
EF2X III: 72.0 dia. × 52.7 mm / 2.8 × 2.1 inch
Weight: EF1.4X III: approx. 225 g / 7.9 oz, EF2X III: approx. 325 g / 11.5 oz
Case: EF1.4X III/EF2X III: LP811
* All specifications are based on Canon's tests and measurements.
* Product specifications and appearance are subject to change without notice.