Canon Digital Camera Lens manual Canon Lens Technology, Canon EF Lens The Heart of the EOS System

CANON LENS TECHNOLOGY

Canon EF Lens: The Heart of the EOS System

L-Series Lenses

Aspherical Elements Wide-angle lenses and fast normal

EF Mount Specialty Lenses

TS-E LENS MOVEMENTS TS-E lenses are capable of tilt and

EOS CAMERAS

At the core of the EOS system, Canon’s renowned EF lens series offers infinite

choices and features for any project, and any budget. With over 50 lenses ranging from fisheye to super-telephoto, with both fixed-length and zoom lenses to fit any photographer’s needs, EF lenses have proven their worth in every photographic context.

Canon designs and manufactures each of their lenses to provide high image quality throughout the entire image area, with natural background blur, and consistent colour regardless of the lens chosen. All Canon EF lenses are designed to be quick, quiet, and highly reliable. With these priorities in mind, Canon’s designs have remained on the cutting edge of technological innovation – if a technology does not exist, Canon invents it. Here’s a closer look at some of the technologies that Canon has incorporated into their EF lenses.

Image Stabilizer Diffractive Optics Ultrasonic Motor

No lenses have a better reputation among professional photographers than those in Canon’s L-series.

Identifiable by a bold red ring around the outer barrel, these lenses are distinctive in their performance through use of optical technologies like

Ultra-low Dispersion UD glass, Fluorite and Aspherical elements and Super Spectra Coating.

FLUORITE/UD ELEMENTS

Avoiding colour fringing, or chromatic

focal-length lenses often suffer from another optical problem; spherical aberration. Spherical aberration occurs when the point of focus of the

spherical aberration of convergence of parallel

spherical lenslight rays by an Aspherical lens

In designing the EF lens mount, Canon engineers gave photographers a lot more than simply a way to quickly attach an interchangeable lens to a camera body. As the communication conduit between camera and lens, the fully electronic mount system has none of the shock, operational noise, abrasion, play, lubrication requirements, slow response, or diminished precision caused by lever operation, or design restrictions related to linkage mechanisms used to transfer data. A lens operation self-test system, using the lens’s built-in microcomputer, can

Canon’s EF Lens system includes many special purpose lenses, ranging from full-frame fisheye, Tilt Shift, macro, and everything in between.

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 is tack-sharp throughout its focus range. Up to three gel filters can be inserted into its built-in rear filter holder.

shift movements, which greatly expand picture-taking possibilities, bringing 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 large apertures or vice versa; shift movements move the lens’s optical axis in parallel, allowing the photographer to change or correct the perspective of their photograph at almost any angle.

EFEF LENSESLENSES

Canon’s Image Stabilizer (IS) technology makes hand-held photography possible in more low-light situations than ever before. When camera shake occurs using

Canon’s use of diffractive optics result in lenses that are both

high performance and more compact than those with traditional refractive designs. While conventional glass lens

In order to achieve critical autofocus, the elements within a camera lens have to move quickly, quietly and precisely. With this in mind, Canon developed the world’s first lens-based

aberration, has been one of the great challenges in the design of telephoto lenses. L-series telephoto lenses like the EF 70-200mm f/2.8L IS USM and EF 300mm f/4.0L IS USM utilise Canon’s Ultra-low Dispersion glass to

spherical lens example

aspherical lens example

even warn of malfunctions through the camera’s LCD readout to help ensure high reliability.

SPEEDLITES

normal lenses without Image Stabilizer technology, the image

elements disperse incoming light, thereby causing chromatic aberration, Canon’s unique multi-layer diffractive elements work together with

Ultrasonic Motor (USM), which spins the lens motor with ultrasonic oscillation energy. Instead of a large, noisy drive-train system, electronic

minimise this effect. The design of UD glass provides outstanding

contrast and

sharpness and

light ray coming through the centre of the lens does not align with the point of focus of the light ray coming through the lens edge. Since there

EF 15mm f/2.8 Fisheye •f/16 •1/640 sec.

POWER

with Image Stabilizer OFF

Image Stabilizer ON

projected to the focal plane also shakes, often resulting in blurred images at shutter speeds less than 1/focal length. When this same movement occurs with an IS lens attached, a special group of lens elements automatically shifts its position, thereby compensating for the shake and stabilising the image. Here’s how Canon’s original Image Stabilizer technology works:

conventional glass optics to cancel the effects of dispersion and minimise or eliminate chromatic aberration. Here’s how it works: Diffractive coatings are bonded to the rear surface of one lens element and the front surface of another. These elements are attached to each other to form a single multi-layer diffractive optics (DO).

multi-layer DO element construction

vibrations created by piezoelectric ceramic elements power the mechanical action of the lens,

Ring-type USM

Micro USM

Gear unit

Micro

USM II

EMD

various lens actuators

providing constant torque, with virtually instantaneous stops and

minimises the splitting of colours as they pass through the

elements, resulting in cleaner colour throughout the image.

Even more effective at suppressing chromatic aberration are Fluorite elements, used in high-end super- telephoto lenses like the EF 300mm f/2.8L IS USM and EF 400mm f/2.8L IS USM. A single Fluorite element has the corrective power of two UD glass elements, giving these L-series lenses their spectacular performance and relatively compact design.

is no sharp point of focus, the image looks blurred. Canon’s Aspherical elements change the curvature from centre to edge, to align the points of focus of the incoming light rays so that the entire image plane appears focused. Aspherical optics also help to correct curvilinear distortion as one would find in ultra-wide-angle

lenses. Finally, Aspherical elements

have an extremely precise variable

curvature of one or both sides,

allowing for more compact and lighter lens designs.

electronic mount -	electronic mount -
camera side	lens side

The EF mount allows for high-speed focus, precise aperture control and preview, automatic compensation with lens extenders, and forward compatibility with new lens technologies like USM, IS and more, as they are developed by Canon.

MACRO

To bring small things into full-sized view, Canon’s EF lens lineup has a number of options for true close-up and macro photography. With four 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

without Tilt Shift Lens

with Tilt Shift Lens

With a normal lens

SUPPLIES
ACCESSORIES	DIGITAL

1: No camera shake			A high-speed
			microcomputer
Group 1		Group 2
			built into the lens
(focusing		(Image
group)		stabilising	analyses electronic
		group)
		Film	signals emitted by
To		Plane
			vibration-detecting
Object	Group 3 to 6
2: Lens front shakes			gyro sensors
downward			and controls a
			mechanism that
3: Image stabilising			moves the image
group counteracting			stabilising lens
downward camera			group parallel to
shake
		Direction of	the focal plane,
			resulting in a
		Group 2
		Movement	sharper image.
How the Image			This compensation
Stabilizer Works			effectively adds up

to three shutter speed steps to your hand-held shooting capability, depending on the IS lens you choose. Canon’s IS lenses are perfect for low light, or situations where a tripod is not convenient.

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The DO element’s dispersion characteristics are reversed when compared with conventional optics, making it possible to cancel chromatic aberrations at each wavelength when conventional and DO elements are combined. In addition to chromatic aberration correction, this technology

also results in smaller lenses, with no compromise in quality. For example, the EF 400mm f/4 DO IS USM lens is approximately 27% shorter and 36% lighter in weight than a conventional 400mm f/4 telephoto lens would be, yet the quality of the resulting image is comparable with one that an L-series lens would produce.

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

starts. USM lenses are both faster and quieter than conventional motor-driven autofocus systems, and draw minimal power from the camera, draining far less critical battery power.

Canon makes two types of Ultrasonic lenses. Ring-type USM-equipped

ring-type USMlenses, found in large aperture and

super telephoto designs, allow manual focusing

without switching

micro USM

out of the auto

mode. Micro USM designs bring the performance benefits of Canon’s USM technology to a wide assortment of affordable EF lenses.

Comparison of optical characteristics between optical glass and Fluorite

Red

GlassBlue

Anomalous dispersion

Red

Blue

Fluorite

fluorite and UD glass

Canon’s exclusive Super Spectra Coating and anti-reflective material inside of lens barrels virtually eliminate internal ghosting and flare in all L-series lenses. Weather sealing

keeps dust out, and allows for photography in less-than-perfect weather conditions.

EF 100mm f/2.8 Macro USM •f/5.6 •1/6 sec.

detail that would be impossible to detect by the eye and give new perspective to extremely minute subjects such as insects or the petals of a small flower.

With a TS-E lens

using shift movements to focus tall building

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ACCESSORIES SHOOTING

PERIPHERALS CASES AND STRAPS