Canon EF400 User Manual

EF400mm f/4 DO IS USM

Instruction

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The Canon EF400mm f/4 DO IS USM lens is a
high-performance, super telephoto lens
dedicated to Canon EOS cameras. Besides
having an Image Stabilizer, it is the world's
first camera lens incorporating a multi-layer
diffractive optical element (DO).
The multi-layer diffractive optical element is a
revolutionary element having the
characteristics of both fluorite and aspherical
elements. It greatly contributes to the lens'
compactness, light weight, and high image
quality.

• "DO" stands for Diffractive Optics.

• "IS" stands for Image Stabilizer.

• "USM" stands for Ultrasonic Motor.

Features

1.

The multi-layer diffractive optical element effectively
corrects chromatic aberrations prone to occur in super
telephoto lenses. It provides high image quality while
maintaining compactness and light weight.

2.

The Image Stabilizer gives the equivalent effect of a
shutter speed two stops faster*.
The lens also has a second image stabilizer mode that is
optimized for following shots of moving subjects.

3.

Ultrasonic motor (USM) for quick and quiet autofocusing.

4.

Manual focusing is available after the subject comes into
focus in autofocus mode (ONE SHOT AF).

5.

The AF Stop button for stopping the AF operation at
anytime.

6.

The lens is compatible with Extender EF1.4X ll and
EF2X ll.

7.

Tight seal structure ensures excellent dust-proof and
drip-proof performance.

8.

Designed for lighter weight with major 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.

Thank you for purchasing a Canon product.

Conventions used in this instruction

Warning to prevent lens or camera malfunction
or damage.

Supplementary notes on using the lens and
taking pictures.

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a Safety Precautions

a Safety Precautions

• Do not look at the sun or a bright light source
through the lens or camera. Doing so could result in

loss of vision. Looking at the sun directly through the
lens is especially hazardous.

• Whether it is attached to the camera or not, do not

leave the lens under the sun without the lens cap
attached. This is to prevent the lens from concentrating

the sun’s rays, which could cause a fire.

• Do not stand on the lens case. Falling off the case
could result in injury.

• Do not stack lens cases. A falling lens case could
cause an injury.

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 leave the lens in excessive heat such as in a
car in direct sunlight. High temperatures can cause

the lens to malfunction.

T

his 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 radio communications.
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 following measures:

• 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.

a Shooting Precautions

If a very bright spotlight like a mercury lamp is
photographed in a dark place with this lens, a
halo of light may occasionally appear around the
light source because of the DO elements.

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Nomenclature

Distance scale (→ 6)

Strap mount (→ 4)

Orientation locking knob (→ 11)

Drop-in filter (→ 12)

Lens mount index (→ 4)

Contacts (→ 4)

Focus mode switch (→ 5)

Focusing distance range selection switch

(→ 5)

Image stabilizer mode selector switch (→ 7)

Image stabilizer switch (→ 7)

Tripod mount (→ 11)

Tripod collar index (→ 11)

AF stop button
(→ 6)

Hood mount (→ 10)

Focusing ring (→ 5)

Rubber ring (→ 4)

For detailed information, reference page numbers are provided in parentheses (→ **).

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• After detaching the lens, place the lens with the
rear end up to prevent the lens surface and
electrical contacts from getting scratched.

• If the contacts get soiled, scratched, or have
fingerprints on them, corrosion or faulty
connections can result. The camera and lens
may not operate properly.

• If the contacts get soiled or have fingerprints on
them, clean them with a soft cloth.

• If you remove the lens, cover it with the dust
cap. To attach it properly, align the lens mount
index and the

K

index of the dust cap as shown
in the diagram, and turn clockwise. To remove it,
reverse the order.

Thread the end of the strap through the strap
mount on the lens and then back through the
clasp on the strap. Pull the strap tight and check
that there is no slack in the clasp.

Attaching the strap

See your camera’s instructions for details on
mounting and detaching the lens.

1. Mounting and Detaching the Lens

The lens mount has a rubber ring for enhanced
water- and dust-resistance. The rubber ring may
cause slight abrasions around the camera's lens
mount, but this will not cause any problems. If the
rubber ring becomes worn, it is replaceable by a
Canon Service Center at cost.

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After autofocusing in ONE SHOT AF mode, focus
manually by pressing the shutter button halfway
and turning the focusing ring. (Full-time manual
focus)

If you autofocus outside the set focusing distance
range, the lens may stop focusing at the start of
the focusing range; however, this is not a
malfunction. Press the shutter release button
halfway again.

You can set the focusing distance range to

3.5 m/11.5 ft. to infinity or 8 m/26.2 ft. to infinity.
By setting the suitable focusing distance range,
the actual autofocusing time can be shorter.

3.

Switching the Focusing
Distance Range

2. Setting the Focus
Mode

To shoot in autofocus (AF) mode, set the focus
mode switch to AF.
To use only manual focusing (MF), set the focus
mode switch to MF, and focus by turning the
focusing ring. The focusing ring always works,
regardless of the focus mode.

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