Specifications

15mm Fisheye 14mm 17mm 20mm 24mm 28mm
35mm 50mm 70mm 85mm 100mm 135mm
200mm 300mm 400mm 500mm 600mm 1200mm
FOCAL LENGTH COMPARISON
Floating System
Typical lenses correct for optical aberrations
only at commonly used focusing distances. Not
surprisingly, at other focusing distances, especially
close range, aberrations compromise image quality.
Rather than using fixed spacings, Canon’s floating
system dynamically varies the gap between
key lens elements based on focusing distance.
Aberrations are effectively suppressed throughout
the focusing range, assuring high image quality
in all shooting situations.
Circular Aperture
Canon lenses featuring circular aperture diaphragms
employ curved blades to create a smoothly rounded
opening as the lens is stopped down. As a result,
out-of-focus background highlights are rendered as
natural-looking rounded shapes rather than as
distracting polygons. These lenses deliver smooth,
consistent stop-down action (even at 10 fps),
near-silent operation and excellent optical
characteristics.
Inner and Rear Focusing
An inner focusing lens has the focusing lens
group(s) in front of the diaphragm, while a rear
focusing lens has the focusing lens group(s) behind
the diaphragm. Both designs allow for compact
optical systems that produce faster AF. And because
the front of the lens does not rotate to focus, filter
orientation remains constant.
AF Stop Feature
Pressing the AF Stop button (featured on several
EF IS telephoto lenses) momentarily locks the AF
to prevent the focus from shifting to a passing
obstruction. After the obstruction has cleared, the
focus will still be on the subject, and you can quickly
resume shooting. AF Stop buttons are positioned
at four locations around the lens grip for easy access.
Full-Time Manual Focusing
Canon EOS cameras with EF lenses deliver impec-
cable AF precision. Manual focusing capability,
nevertheless, can enhance flexibility. Canon EF
lenses with full-time manual focusing enable the
photographer to manually tweak focus without
switching out of AF mode. Since AF action does
not cause the focusing ring to turn, it can be made
wider for improved grip and comfort.
Specialty Lenses
EF-S Lenses — Designed for Canon Digital EOS 30D,
Digital Rebel XTi and Digital Rebel XT cameras
with APS-C sized sensors (with a 1.6x crop factor),
Canon’s EF-S lenses take advantage of the sensor’s
smaller size to deliver optimized performance in
compact, lightweight designs. The EF-S 17-85mm
f/4-5.6 IS USM is a perfect example of this new
technology. With a compact design, a 35mm
equivalent range of 27-136mm, and Image
Stabilization technology, it’s a superlative walk-
around lens… possibly the only lens you’ll need
to enjoy basic Canon digital SLR photography.
Fisheye — Perfect for super wide-angle and special
effect photography, Canon’s full-frame fisheye
can focus as close as eight inches (0.2m), and
delivers exceptionally sharp images throughout
its focus range. Up to three gel filters can be inserted
into its built-in rear filter holder.
TS-E — TS-E lenses are capable of tilt and shift
movements, which bring many of the advantages
of technical view cameras to the EOS System. Tilt
movements alter the angle of the plane of focus
between the lens and film plane, making broad
depth-of-field possible even at larger apertures;
shift movements slide the lens’s optical axis along
the film/sensor plane, enabling photographers
to correct or alter perspective at almost any angle.
Macro — Canon’s EF lens lineup has a number of
options for true close-up and macro photography.
With five macro lenses for precision, and three
screw-on close-up lenses for convenience—in
addition to Life-Size Converter EF and two Extension
Tubes—Canon’s macro lenses and close-up
accessories can uncover detail that is impossible
for the unaided human eye to detect.
EF Mount
In designing the EF lens mount, Canon engineers
gave photographers a lot more than a way to quickly
attach a lens to a camera body. As the commu-
nication conduit between camera and lens, this
fully electronic mount system has none of the shock,
operational noise, abrasion, play, lubrication
requirements, slow response, lever operation
limitations, or other design restrictions related to
mechanical linkage mechanisms. A self-test system,
using the lens’s built-in microcomputer, can even
warn of malfunctions through the camera’s display.
The EF mount makes possible high-speed autofocus,
precise aperture control and preview, automatic
compensation with lens extenders, and forward
compatibility with new lens technologies—such
as USM and IS—as they are developed by Canon.
Dust- and Water-Resistant
Construction
L Series EF telephoto
lenses are highly dust-
and water-resistant
thanks to rubber seals
at the switch panels,
exterior seams, drop-in
filter compartments and
lens mounts. Moving
parts, such as the focusing ring and switches,
are also designed to keep out environmental
contaminants, providing reliable performance
under harsh conditions.
20
Photo 1a: TS-E 45mm f/2.8 – Reverse tilt and shift greatly
reduces the range on which focusing is possible.
With a normal lens With a TS-E lens
Depth of field with tilt movements
Plane of optimum focus
Film plane
EF LENSES
21
Astigmatism
Floating Effect
(TS-E 24mm f/3.5L)
Closest
shooting
distance
TS-E 24mm f/3.5L Floating System
Floating
Focal plane
Photo 1b: The lens’s tilt mechanism is used to achieve a pan
focus effect that allows focusing all the way back.
Photo 2a: TS-E 24mm f/3.5L – Shift was used to adjust the image
to keep the building perpendicular all the way to the top.
Photo 2b: Without using shift causes the image of the building to
lean in at the top.
Tilt Movements – If you want to bring the entire field of flowers
into focus, you could use a wide-angle lens and a small aperture
to obtain a wide depth of field. With tilt movements, you can
achieve this wide depth of field even at the maximum
aperture. By tilting the center of the TS-E lens barrel, you
can tilt the lens so that the plane of focus is uniform on
the focal plane (Photo 1b). Reversing it will have the
opposite effect, narrowing the depth of field (Photo 1a).
Shift Movements – Normally, when you point your camera
up at a tall building, the building will look slimmer toward
the top. It becomes trapezoidal (Photo 2b). This perspective
effect is more pronounced with shorter focal lengths,
distorting the building even more. By keeping the camera
level, and using the shift function to raise the lens instead,
this perspective effect can be corrected. With the camera’s
focal plane set parallel to the building, shifting the lens
upward will obtain a more rectangular-looking building
(Photo 2a).
About Macro Magnification
A life-size macro lens—that is, a 1x magnification—records an
image on film at its actual size. If you’re photographing a
flower, for example, and it has a diameter of 1 in., it will occupy
1 in. of your actual slide or
negative. With a digital SLR, at
1x magnification, the image
projected onto your camera’s
sensor will likewise be the
same size at the sensor plane
as the actual subject itself.
Other macro lenses have lower
or higher magnifications. A
lens with 0.5x magnification
will produce an image on film
that is half the size of the
actual subject. Your 1 in.
flower, then would only occupy
0.5 in. on film.
In the other direction, a 5x
magnification lens will
convert the 1in. flower to a 5
in. diameter image. Since
the entire image won’t fit in
the frame of your film, you
will have an enlarged image
of a detail of the flower.
Magnification is not the same
as focal length. A 50mm lens
and a 180mm might both be
macro lenses with, for example,
1x magnification. The advan-
tage of the longer lens is that
it allows greater distance from
a subject. You would choose
the 180mm macro lens to
photograph a butterfly or a
bird. The 50mm lens would
be more suitable for a subject
that won’t move away when
you approach it.
0.5x
1.0x
0.25x
5.0x
3.0x
EF 15mm f/2.8 Fisheye •f/16 •1/640 sec.
EF 100mm f/2.8 Macro USM •f/5.6 •1/6 sec.
Using Tilt Movements to Focus an Oblique Subject Plane Using Shift Movements to Focus Tall Building
TS-E Movements
Tilt movements alter the angle of the plane of focus between the lens and focal plane, and shift movements move the lens’s
optical axis in parallel.
EF LENSES
180° 114° 104° 94° 84° 75°
63° 46° 34° 28° 30' 24° 18°
12° 8° 15' 6° 10' 5° 4° 10' 2° 5'