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Canon EOS Rebel T2i EF-S 18-55IS II Kit Brosur

Taken with EF 100-400mm f/4.5-5.6L IS USM

The standard settings of the Optical Image

During normal shooting situa-

Stabilizer are set so that it is most effective

tions, sudden camera move-

when photographing stationary subjects.

ment in rotational camera angle can cause

However when panning with a moving subject is

significant image blur. During macro or close-up

attempted (tracking of the subject horizontally

photography however, the image blur caused by

or vertically), the shake-correction of the OIS may

linear camera shake—when the camera moves

inadvertently over-compensate and interfere with

parallel to the subject—is more pronounced.

framing. To help resolve this, Canon developed

Optical Image Stabilizer is optimized to counteract

Optical Image Stabilizer Mode 2. In this mode, if

rotational or angular camera shake and works

you move the lens to follow a subject for a pre-

well for most camera shooting situations. To

determined time, the Optical Image Stabilizer

help compensate for linear camera shake, a new

does not correct for the intentional panning

acceleration sensor determines the amount of

while continuing to correct any camera shake

shift-based camera movement. The new Canon

that's perpendicular to the panning motion. The

Hybrid Image Stabilizer technology employs a

result is a virtually smooth viewfinder image as

highly sophisticated algorithm that combines

you follow the moving subject.

the feedback of both the acceleration sensor

Linear Camera Shake

and angular velocity sensor (found in current

OIS technology) and moves the image stabilizer

lens elements, effectively compensating for both

rotational and linear camera shake. Hybrid IS

dramatically enhances the effects of Optical

Image Stabilizer especially during macro shooting,

which may be difficult for conventional image

stabilization technologies.

with virtually instantaneous stops and starts.

Canon's use of diffractive optics (DO) results in

USM lenses also draw minimal power from the

high-performance lenses that are much smaller and

camera, ensuring longer battery life. Canon makes

lighter than traditional designs. Canon's unique

two types of Ultrasonic Motor lenses. Ring-type

multilayer diffractive elements are constructed

USM lenses, found in

by bonding diffractive coatings to the surfaces of

large aperture and super-

two or more lens elements. These elements are

telephoto designs, permit

then combined to form a single multilayer DO

manual focusing without

element. Conventional glass lens elements disperse

first switching out of the

incoming light, causing chromatic aberration.

auto mode. Micro USM

The DO element's dispersion characteristics are

designs bring the perform-

designed to cancel chromatic aberrations at various

ance benefits of Canon's

wavelengths when combined with conventional

USM technology to a

glass optics. This technology results in smaller

wide assortment of

lenses with no compromise in image quality.

affordable EF lenses.

Canon has also developed a new triple-layer type

DO lens that uses an advanced diffractive grating

to deliver excellent performance, with superb

Most highly regarded among professional photog-

control of color fringing. This configuration is ideal

raphers, Canon L-series lenses are distinguished

for zoom lens optics and provides significant

by a bold red ring around the outer barrel. What

makes them truly distinctive, however, is their

remarkable optical performance — the result of

sophisticated Canon technologies, such as Ultra-

low Dispersion UD glass, Fluorite and Aspherical

elements and Super Spectra Coating.

Reducing color fringing, or chromatic aberration,

has been one of the great challenges in the design

of telephoto lenses. L-series telephoto lenses –

EF 400mm f/4 IS DO USM •f/4 • 1/1250 sec.

like the EF 70-200mm f/2.8 IS II USM and EF

Refractive Optical Element

300mm f/4L IS USM – employ Canon's Ultra-low

Chromatic aberrations

Refractive Optical Element

and Multi-Layer Diffractive

Dispersion glass to minimize this effect, providing

Optical Element Combined

much improved contrast and sharpness. Even

Image formation in the blue, green

and red wavelength order

more effective at suppressing chromatic aberration

Multi-Layer Diffractive Optical Element

Chromatic aberrations reversed from

that of a refractive optical element

Chromatic aberration canceled out

Image formation in the red, green and

blue wavelength order

Red

Green

Blue

Correction of Chromatic Abberation by the Multi-Layer

Anomalous

dispersion

Diffractive Optical Element.

reductions in size. A good example is the

EF 70-300mm f/4.5-5.6 DO IS USM lens, which

is 28 percent shorter than the EF 70-300mm

f/4-5.6 IS USM lens.

Comparison of optical characteristics between

Canon developed the world's first lens-based

are Fluorite elements, used in high-end super-tele-

Ultrasonic Motor (USM) to power the lens autofocus

photo L-series lenses. Composed of crystallized

mechanism. Instead of large noisy drive trains

calcium fluoride (CaF

although costly, has roughly the corrective power

lenses employ the minute electronic vibrations

of two UD-glass elements, giving these L-series

created by piezoelectric ceramic elements. The

lenses their spectacular performance and relatively

focusing action of the lens is fast and quiet,

compact design.

EF LENSES

Wide-angle lenses and fast normal-focal-length

lenses often suffer from spherical aberration.

When the light rays coming through the center

of the lens do not converge at the same point as

light rays coming through the lens edge, the

Ring-type USM

Spherical aberration

Convergence of parallel light

of spherical lens.

rays by an Aspherical lens.

Micro USM

image appears blurred because there is no sharp

point of focus. Canon's Aspherical elements use

a varying curved surface to ensure that the entire

image plane appears focused. Aspherical optics

also help to correct curvilinear distortion as one

might find in ultra wide-angle lenses. Canon

designs aspherical elements with extremely

precise variable curvature of one or both sides,

making possible lighter, more compact lenses.

SWC is a new proprietary lens coating that helps

control ghost and flare to a far greater degree

than with earlier coating technologies. Utilizing

SWC technology on large-curvature lens elements

that are mainly found in wide-angle lenses,

will significantly minimize the occurrence of

ghosting and flare caused by reflected light in

environments that have posed problems. SWC

is used on the latest Canon wide angle lens,

EF 24mm f/1.4L II USM.

Red

Glass

Blue

Red

EF 24mm f/1.4L II USM •f/6.3 •13 sec.

Blue

Fluorite

Focus Preset enables you to program a focusing

optical glass and Fluorite

distance in the camera's memory. Normal picture

taking and focusing are unaffected by preset

distances. For example, at a soccer game, you

), a single Fluorite element,

Focus Preset the goal area. Shoot normally

elsewhere on the field, but once the action moves

toward the goal, the user can instantly return to

the preset distance by turning a ring on the lens.