EOS Documentation Project

EF 28-105mm f/3.5-4.5 USM

by Gary Fisher

Contents

• Introduction

  Parts  Description 

• Operation

  Mounting  Removal  Manual Zoom  Manual Focus  Auto Focus  Full Time Manual Focus  Aperture 

• Accessories

  Lens Cap  Hood  Filters  CloseUp  Teleextender  Extension Tubes  Case 

• Incompatibilties

  EF-M body  Flash 

• Precautions
• Lens Care

  Storage  Service 

• Specifications

  Released  Discontinued  Dimensions  Weight  Filter Mount  Optics  Focus mechanism  Rotating Filter Mount  Focus Range  Autofocus Motor  Full Time Manual  Focal Length  Magnification  Angle of view  Aperture blades  Aperture Range 

• Revision History
• Comments

Introduction

Parts

              Click above images to view larger versions
From front to back: Front lens cap; 58 mm filter thread; bayonet fitting for lens hood; Zoom ring; Focusing ring; Distance scale in ft and m; IR focus adjust marks for 28mm, 35mm, 50mm and 105mm; AF/M lens mode switch; Raised Red Dot for lens-to-camera alignment; EF Camera mount (metal); Rear lens cap.

Description

This lens is a general purpose standard-range zoom lens with autofocus and electronic diaphragm for use on Canon EOS series cameras.   The lens can zoom from wide angle to short telephoto and can be used for general photography. The lens features an Utrasonic Motor (the USM in the lens title), which provides quick silent autofocusing capabilities. There are two types of USM motors; this lens features ring type USM, which also allows for full time manual focusing without the need to change into manual focusing mode on the lens.

Operation

Mounting

Prepare camera body by removing body cap or previous lens (see next section). Match the raised red dot on the lens with the red dot on the camera. Gently twist the lens clockwise until the lens locking pin clicks into place. Ensure that the lens is securely locked before using the camera.

Removal

Depress the lens release button fully. Rotate the lens counterclockwise until the raised red dot on the lens matches the rot dot on the camera. Remove the lens carefully.

Warning: Do not rest the lens on the camera mount, otherwise damage can occur to the delicate electronic contacts. When not mounted on a camera the rear lens cap should always be in place to prevent damage to the electrical contacts and the rear glass element of the lens.

Manual Zoom

In the picture-taking position turn the zoom ring in the clockwise direction to obtain a wider angle of view. To narrow the angle of view (to zoom in or go toward the telephoto range of the lens) turn the zoom ring in the anti-clockwise direction.

Manual Focus

Slide the lens mode switch on the lens to "MF". This disengages the autofocus motor. Look through the camera viewfinder at the subject, then rotate the focusing ring on the lens until you see the viewfinder image is as sharp as possible¹. The front part of the lens does not move or rotate during focusing. If you manually focus while holding the shutter release button half-depressed, the focus sensors in the camera may indicate in the viewfinder when sharp focus is detected in a focusing zone.

Note 1: When photographing at very close range, it may be easier to focus by leaving the focusing ring set to the closest focus setting, and moving the camera back and forth until sharp focus is achieved.

Auto Focus

Slide the lens mode switch on the lens to "AF". This engages the autofocus motor. Look through the camera viewfinder and position a focusing zone over the subject. Hold the shutter release button half-depressed to activate autofocus¹. The front part of the lens does not move or rotate during autofocus. When sharp focus is detected, the camera will indicate in the viewfinder with a light, and may also beep softly. If the autofocus sensors cannot detect sufficient detail, the viewfinder focus indicator will blink, indicating out-of-focus². When the lens is switched to "AF" mode, it is possible to focus manually without first setting the lens mode switch to "MF". This feature is commonly used in conjunction with a custom function on the camera body (CF4) which shifts the autofocus activation from the shutter release to the AE-Lock button on the rear of the camera.

Note 1: On some camera bodies a custom function allows autofocus activation to be shifted from the shutter release to the AE-Lock button on the rear of the camera.
Note 2: Autofocus accuracy can be enhanced by using the autofocus assist beam on some camera bodies and on some flash units.

Full Time Manual Focus

As this lens has full-time manual (FTM) focusing, it is not necessary to switch it to the "MF" position. The user is able to focus manually when the lens is switched to "AF" mode without first setting the lens mode switch to "MF". This feature is commonly used in conjunction with a custom function on the camera body (CF4) which shifts the autofocus activation from the shutter release to the AE- Lock button on the rear of the camera.

Aperture

All Canon EF lenses have an electronic diaphragm, which means that the lens aperture is controlled electronically from the EOS camera body, rather than by the traditional aperture ring. For instructions on changing the aperture setting of any Canon EF (or EF compatible) lens, please refer to the operating instructions for the camera body.

Accessories

Lens Cap

58mm part number E-58U

Hood

Bayonet hood part number EW-63

Filters

58mm thread for filter accessories. Multiple filters should not be used simultaneously to avoid vignetting particularly at the 28mm setting(vignetting is a darkening of the corners of the resulting photgraph due to the rims of the stacked filters blocking part of the field of view of the lens).

CloseUp

58mm close-up lenses 250D (part number C543871), 500 (part number C543931) & 500D (C543891). The 250D is the recommended choice as it is suited to lenses with a focal length in the range of 30mm to 135mm. The 500D and 500 while usable are more suitable for lenses with a focal length the range of 70mm to 300mm.

Teleextender

This lens is not compatible with either Canon EF 1.4× or EF 2× Tele- extenders which have a protruding front element. Third Party teleconverters designed for Canon Autofocus mount can be often be used successfully, but compatibility is not guaranteed.

Extension Tubes

Compatible with EF-12 and EF-25 extension tubes

Case

LH-C13 (Hard Case), ES-C13 (Soft Case)

Incompatibilties

EF-M body

The EF-M camera does not have autofocus sensors. All EF lenses operate in manual focus mode only. As this lens has full-time manual focusing, it is not neccessary to switch it to the "MF" position.

Flash

If the accessory lens hood is used, the built in flash of EOS bodies (where fitted) will be partly obscured by the lens at the wide angle settings. This manifests as a darker semicircle in the lower half of the picture frame.

There are no flash related problems when using this lens without the lens hood fitted.

Precautions

Do not rest the lens on the camera mount, otherwise damage can occur to the delicate electronic contacts. When not mounted on a camera the rear lens cap should always be in place to prevent damage to the electrical contacts and the rear glass element of the lens.

Do not disassemble the lens - there are no user serviceable parts inside.

As with all precision electrical and mechanical equipment do not expose the lens to water, particularly salt water.

Do not attempt to mount the lens on any camera body other than a Canon EOS series camera as this could result in damage to both the lens and camera body¹. Please note that earlier model Canon cameras using FD or earlier mounts are also not compatible with EF lenses.

Note 1: Adaptors may be available to allow the use of EF lenses on other camera bodies but care should to taken to ensure that no damage results from their use.

Lens Care

Storage

When not mounted on a camera body, store with the front and rear lens caps in place to prevent accidental scratching or other damage.

Store in dry conditions to prevent the possible build up of fungus between the glass elements of the lens.

Service

There are no user serviceable parts - please return the lens to an authorised Canon service centre for adjustment or repair.

Specifications

Released

November 1992

Discontinued

October 2000
This lens was replaced by the 28-105 f3.5-4.5 USM II in October 2000. Optically and mechanically they are identical, but the with the new version the appearance has been slightly updated, although the differences are minimal and easily missed.

Dimensions

Maximum Diameter x Length:
72.0mm x 75mm / 2.8in x 3.0in

Weight

375g / 13.2oz

Filter Mount

58mm threaded mount for front mounted accessory filters

Optics

15 elements in 12 groups

Focus mechanism

This lens focuses using the inner/rear lens elements. The front elements do not move during focusing and the front element and lens barrel are stationary during focusing.

Rotating Filter Mount

Because the front elements do not move or rotate during focusing this lens is ideal for use with filters such as polarisers.

Focus Range

0.5 metres / 1.6 feet ~ infinity.

Autofocus Motor

Ring type UltraSonic Motor (USM)

Full Time Manual

As with all ring type USM lenses this lens feature Full Time Manual (FTM) focusing.

Focal Length

28mm ~ 105mm

Magnification

Lens alone	Maximum 0.19
12mm extension	0.53-0.12
25mm extension	0.75-0.27
with 250D lens
with 500/500D lens

Angle of view

for 35mm film

	28mm	105mm
Diagonal	75°	23° 30'
Vertical	46°	13°
Horizontal	65°	19° 20'

Aperture blades

Early versions of this lens had 5 blades, but at some point this was changed to 7 blades. There was no official announcement or version change to mark this difference.

Aperture Range

Focal length
28 mm		f/3.5~f/22
105 mm		f/4.5~f/27

Revision History

v0.11b2002Sep04 jul: minor reformat
v 0.11 2001Jan27 jul: Minor corrections
v0.10 2001Jan08 Gary Fisher: First Draft

Comments

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