Sigma 18-50mm f/3.5-5.6 DC Autofocus Zoom Aspherical Lens User Manual

Introduction

This manual provides detailed instructions for the proper use and care of your Sigma 18-50mm f/3.5-5.6 DC Autofocus Zoom Aspherical Lens. Designed exclusively for digital SLR cameras, this compact and lightweight lens offers versatile zoom capabilities and high optical performance.

The lens features an image circle optimized for digital SLR camera sensors, ensuring high-quality images throughout its entire zoom range. It incorporates aspherical lens elements to correct various aberrations and is treated with coatings to minimize flare and ghosting, common issues with digital sensors.

Figure 1: The Sigma 18-50mm f/3.5-5.6 DC Autofocus Zoom Aspherical Lens. This image shows the lens from a front-side perspective, highlighting the zoom and focus rings, as well as the focal length markings (18mm, 24mm, 28mm, 35mm, 50mm) and distance scale (in meters and feet). The lens barrel is black with white and yellow markings, and the Sigma brand name is clearly visible.

Setup

Attaching the Lens:
Align the mounting index on the lens barrel with the corresponding index on your camera body. Rotate the lens clockwise (for Canon EF mount) until it clicks securely into place. Ensure the lens is firmly attached before use.
Removing the Lens:
While pressing the lens release button on your camera body, rotate the lens counter-clockwise until it stops. Carefully remove the lens from the camera body. Always attach the rear lens cap immediately after removal to protect the rear element and contacts.
Attaching the Lens Hood:
The supplied lens hood helps to block extraneous light and reduce flare. Align the hood with the front of the lens and twist until it locks into position. For storage, the hood can be reversed and mounted on the lens.

Operating Instructions

Autofocus (AF) Operation

Set the AF/MF switch on the lens barrel to "AF".
Ensure your camera's focus mode is set to autofocus.
Press the camera's shutter button halfway down to activate autofocus. The lens will adjust focus automatically.

Manual Focus (MF) Operation

Set the AF/MF switch on the lens barrel to "MF".
Rotate the focus ring on the lens barrel to manually adjust focus. Use your camera's viewfinder or Live View display to achieve sharp focus.
The distance scale on the focus ring provides an easy reference for focusing distance.

Zoom Operation

Rotate the zoom ring on the lens barrel to change the focal length between 18mm and 50mm.
The focal length markings (18, 24, 28, 35, 50) indicate the current zoom position.

Macro Photography

This lens is capable of macro photography with a maximum magnification ratio of 1:3.5.
The minimum focusing distance is 25cm (9.8 inches) at all focal lengths, allowing for close-up shots.

Maintenance and Care

Cleaning the Lens: Use a soft, lint-free cloth or a lens brush to remove dust. For smudges or fingerprints, use a specialized lens cleaning solution applied to a microfiber cloth, not directly to the lens surface.
Storage: When not in use, store the lens with both front and rear caps attached in a cool, dry place away from direct sunlight and extreme temperatures. Avoid storing in areas with high humidity to prevent mold growth.
Handling: Avoid dropping or subjecting the lens to strong impacts. Do not force any moving parts.
Water and Dust: This lens is not weather-sealed. Avoid exposure to rain, moisture, or excessive dust.

Troubleshooting

Problem	Possible Cause / Solution
Lens does not autofocus.	Ensure the AF/MF switch on the lens is set to "AF". Check your camera's focus mode settings. Insufficient light or low contrast in the subject may hinder autofocus. Try focusing on an area with more contrast.
Images appear blurry or out of focus.	Verify that the lens is properly attached to the camera body. Check if the focus mode is set correctly (AF or MF). Ensure shutter speed is fast enough to prevent camera shake, especially in low light or at longer focal lengths. Clean the lens elements if smudges or dust are present.
Lens not recognized by camera.	Remove the lens and reattach it, ensuring a secure connection. Clean the electrical contacts on both the lens and camera body with a clean, dry cloth. Ensure camera firmware is up to date.

Specifications

Model Number: 521101
Focal Length: 18-50mm
Maximum Aperture: f/3.5-5.6
Lens Type: Zoom, Aspherical, DC (Digital Compatible)
Compatible Mountings: Canon (EF-S compatible), Sigma SA, Nikon, Pentax
Minimum Focusing Distance: 25 cm (9.8 inches)
Maximum Magnification Ratio: 1:3.5
Filter Size: 58mm
Dimensions (Diameter x Length): Approximately 62mm x 67.5mm (2.44 x 2.66 inches)
Product Dimensions: 5.3 x 4.3 x 4 inches
Item Weight: 8.8 ounces (250g)
Date First Available: June 17, 2003

Warranty and Support

For warranty information and technical support, please refer to the official Sigma website or contact your local authorized Sigma dealer. Keep your purchase receipt as proof of purchase for warranty claims.

For further assistance, you may also visit the product page on Amazon.

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Sigma 521101