Canon EF 100-300mm f/4.5-5.6 USM Telephoto Zoom Lens User Manual

1. Product Overview

The Canon EF 100-300mm f/4.5-5.6 USM is a highly practical and portable telephoto zoom lens designed for Canon SLR cameras. Its compact design is achieved through five zoom groups, resulting in a length of only 4.8 inches (121.5mm). The lens features a rear focusing system, which ensures that the lens length does not change and the front element does not rotate during focusing. This design maintains the integrity of any attached filters and contributes to quick and quiet autofocusing.

Key Features:

• EF mount for compatibility with Canon EOS cameras.
• Telephoto zoom lens with a versatile 100-300mm focal length range.
• Maximum aperture of f/4.5-5.6.
• Inner focusing system for stable operation.
• Full-time manual focus override.
• Ring-type UltraSonic Motor (USM) for fast, quiet, and precise autofocus.

Figure 1: Front view of the Canon EF 100-300mm f/4.5-5.6 USM Telephoto Zoom Lens.

2. Setup

Attaching the Lens:

1. Ensure the camera is powered off.
2. Remove the rear lens cap from the lens and the body cap from the camera.
3. Align the red index mark on the lens with the red index mark on the camera body.
4. Insert the lens into the camera mount and turn it clockwise until it clicks into place.

Detaching the Lens:

1. Ensure the camera is powered off.
2. While pressing the lens release button on the camera body, turn the lens counter-clockwise until it stops.
3. Remove the lens and attach the rear lens cap. Attach the body cap to the camera.

Figure 2: Rear mount of the lens, showing electrical contacts for camera communication.

3. Operating Instructions

Focusing Modes (AF/MF):

This lens supports both autofocus (AF) and manual focus (MF). A switch on the side of the lens allows you to select the desired mode.

• AF (Autofocus): Set the switch to 'AF'. The camera will automatically focus when the shutter button is pressed halfway. The Ring-type USM provides fast and quiet autofocus performance.
• MF (Manual Focus): Set the switch to 'MF'. Rotate the focusing ring on the lens to adjust focus manually. This lens also features full-time manual focus, allowing you to fine-tune focus manually even when in AF mode, without needing to switch modes.

Zooming:

To change the focal length, rotate the zoom ring on the lens. The lens offers a zoom range from 100mm (wide telephoto) to 300mm (super telephoto). The current focal length is indicated on the lens barrel.

Aperture Control:

The aperture (f/4.5-5.6) is controlled electronically by the camera. Select your desired shooting mode (e.g., Aperture-priority AE, Manual) on your camera to adjust the aperture setting.

Using Filters:

The front of the lens is threaded to accept screw-in filters. Since the lens uses a rear focusing system, the front element does not rotate during focusing, which is beneficial when using polarizing or graduated neutral density filters.

Figure 3: Side view of the lens, showing the zoom ring and focus ring.

4. Maintenance

Cleaning the Lens:

• Lens Elements: Use a lens blower brush to remove dust. For smudges or fingerprints, use a clean, soft lens cloth specifically designed for optical surfaces, along with a small amount of lens cleaning fluid. Apply fluid to the cloth, not directly to the lens.
• Lens Body: Wipe the lens body with a soft, dry cloth. Avoid using organic solvents to clean the lens body.

Storage:

• Always attach the front and rear lens caps when the lens is not in use.
• Store the lens in a cool, dry, and well-ventilated area, away from direct sunlight and high humidity.
• Avoid storing the lens in areas prone to extreme temperature changes.

Handling Precautions:

• Avoid dropping or subjecting the lens to strong impacts.
• Do not leave the lens in direct sunlight for extended periods, as this can damage internal components.
• Keep the lens away from magnetic fields.

5. Troubleshooting

Autofocus Not Working:

• Ensure the AF/MF switch on the lens is set to 'AF'.
• Check that the lens is securely attached to the camera body.
• Verify that the camera's autofocus settings are correctly configured.
• Clean the electrical contacts on both the lens mount and camera body with a clean, dry cloth.

Blurry Images:

• Ensure the lens elements are clean and free from smudges or dust.
• Check that the focus is correctly set for your subject.
• Use a faster shutter speed or a tripod to prevent camera shake, especially at longer focal lengths (300mm).
• Verify that the aperture setting is appropriate for your desired depth of field.

Lens Not Recognized by Camera:

• Remove and reattach the lens, ensuring it clicks securely into place.
• Clean the electrical contacts on both the lens and camera body.
• Ensure the camera's firmware is up to date.

6. Specifications

7. Warranty and Support

Warranty Information:

This product may be covered by a limited warranty. For specific warranty details, including duration and coverage, please refer to the documentation provided at the time of purchase or contact your retailer. A typical warranty may include a 14-day satisfaction guarantee and a 90-day parts and labor warranty, depending on the seller and region.

Customer Support:

For technical assistance, service, or inquiries regarding your Canon EF 100-300mm f/4.5-5.6 USM Telephoto Zoom Lens, please contact Canon customer support or visit the official Canon website for your region. You may need to provide the product model number (2565A003) and serial number for support.