Sigma 28-70mm F2.8 EX Aspherical Lens for Canon-AF Camera User Manual

Introduction

This manual provides essential instructions for the proper use and care of your Sigma 28-70mm F2.8 EX Aspherical Lens, designed specifically for Canon-AF SLR cameras. This lens offers a versatile focal range and a constant f/2.8 maximum aperture, making it suitable for various photographic situations. Please read this manual thoroughly before using the lens to ensure optimal performance and longevity.

Figure 1: Sigma 28-70mm F2.8 EX Aspherical Lens. This image illustrates the overall appearance of the lens.

Setup

Attaching the Lens

1. Ensure both the camera and the lens are clean and free of dust.
2. Remove the rear lens cap from the lens and the body cap from the camera.
3. Align the mounting index (usually a red dot or white line) on the lens barrel with the corresponding index on the camera body.
4. Insert the lens into the camera's lens mount and rotate it clockwise until it clicks into place. Do not force the lens.

Figure 2: Illustrative image of a lens being attached to a camera body. Ensure alignment marks are matched before rotating.

Removing the Lens

1. Turn off the camera.
2. While pressing the lens release button on the camera body, rotate the lens counter-clockwise until it stops.
3. Carefully remove the lens from the camera mount.
4. Attach the rear lens cap to the lens and the body cap to the camera to protect the sensor and lens elements.

Operating the Lens

Focusing

This lens supports both autofocus (AF) and manual focus (MF). The focus mode switch is located on the side of the lens barrel.

• Autofocus (AF): Set the switch to 'AF'. The camera will automatically focus when the shutter button is half-pressed.
• Manual Focus (MF): Set the switch to 'MF'. Rotate the focus ring on the lens barrel to achieve sharp focus. Use the camera's viewfinder or LCD screen to assist with focusing.

The minimum focusing distance for this lens is 15.7 inches (approximately 40 cm) across all focal lengths.

Zooming

To change the focal length, rotate the zoom ring on the lens barrel. The lens offers a focal range from 28mm (wide-angle) to 70mm (short telephoto). The current focal length is indicated by markings on the lens barrel.

Figure 3: Illustrative image showing the location of the focus and zoom rings on the lens barrel.

Aperture Control

This lens features a constant maximum aperture of F2.8 throughout its zoom range. Aperture settings are controlled via the camera body. Refer to your camera's instruction manual for details on adjusting aperture.

Using Filters

The lens incorporates helical focusing, which means the front lens barrel does not rotate during focusing. This design is convenient for using polarizing filters or other filters that require precise orientation.

Maintenance

Cleaning the Lens

• Use a blower brush to remove dust and loose particles from the lens surfaces.
• For smudges or fingerprints, apply a small amount of lens cleaning solution to a clean microfiber cloth and gently wipe the lens in a circular motion from the center outwards.
• Never use abrasive materials, solvents, or household cleaners on the lens.

Storage

• Always attach the front and rear lens caps when the lens is not in use.
• Store the lens in a cool, dry place, away from direct sunlight and extreme temperatures.
• If storing for extended periods, consider using a dehumidifying agent to prevent mold growth.

Troubleshooting

• Lens not recognized by camera: Ensure the lens is securely attached and clicked into place. Turn the camera off and on again. Clean the electrical contacts on both the lens and camera body with a clean, dry cloth.
• Autofocus not working: Check if the lens is set to 'AF' mode. Ensure there is sufficient light and contrast in the scene for the camera's autofocus system to operate effectively.
• Images are blurry: Verify that the lens is properly focused. Check the camera's shutter speed to ensure it's fast enough to prevent motion blur, especially in low light or with moving subjects. Ensure the lens elements are clean.

If problems persist, consult your camera's manual or contact Sigma customer support.

Specifications

Warranty and Support

For information regarding warranty coverage, service, or technical support, please refer to the warranty card included with your product or visit the official Sigma Corporation of America website. Keep your purchase receipt as proof of purchase for warranty claims.

Manufacturer: Sigma Corporation of America