The Canon EF 17-40mm f/4L USM is a high-performance wide-angle zoom lens from Canon’s L-series, designed for full-frame Canon EF-mount DSLRs. Offering a constant f/4 maximum aperture, this lens provides consistent illumination across its zoom range, making it suitable for various shooting conditions. The lens boasts an advanced optical design that incorporates one Super Ultra-Low Dispersion (Super UD) element and three aspherical elements. These elements effectively reduce both chromatic aberrations and spherical distortions, ensuring high sharpness, clarity, and color fidelity throughout the frame. Additionally, the lens features a Super Spectra coating on individual elements, which helps minimize flare and ghosting, improving contrast and color accuracy in challenging lighting situations.

In terms of focusing, the EF 17-40mm f/4L USM is equipped with a ring-type Ultrasonic Motor (USM) and an internal focusing system that provides fast, quiet, and precise autofocus performance. The lens also allows for full-time manual focus override, giving the user more control over focus adjustments. As part of the L-series, the EF 17-40mm f/4L USM is built to withstand tough conditions, with weather sealing that protects against dust and moisture. The lens also features a rounded seven-blade diaphragm, which contributes to beautiful out-of-focus areas, ideal for shallow depth of field and selective focus techniques. Additionally, it includes a rear filter holder that accommodates up to three cut gel filters, offering more flexibility for creative photography.

Feature:

• Wide-angle 17-40mm zoom lens for full-frame Canon EF-mount DSLRs
• Constant f/4 aperture for consistent illumination throughout the zoom range
• Super UD and aspherical elements to reduce chromatic and spherical aberrations
• Super Spectra coating for improved contrast and color accuracy in challenging light
• Ring-type USM for fast, quiet autofocus with full-time manual focus override
• Weather-sealed construction for use in adverse environmental conditions
• Rounded seven-blade diaphragm for smooth bokeh
• Rear filter holder for up to three gel filters

Specifications: