Canon EF 17-40mm f/4.0L USM

Canon EF

Review

The Canon EF 17-40mm f/4.0L USM is a versatile ultra-wide zoom lens that is well-regarded among Canon users, particularly for landscape and architecture photography. This lens combines a robust build quality with excellent image performance, making it a favorite for both amateur and professional photographers.

Build Quality and Design

Constructed as part of Canon's prestigious L series, the 17-40mm f/4.0L features a solid, weather-sealed body that can withstand tough shooting conditions. The lens has a relatively lightweight design for a standard zoom, weighing in at approximately 1.2 pounds (around 500 grams). The lens includes a rubber seal around the mount, which provides a level of protection against moisture and dust, enhancing its outdoor shooting capabilities.

The zoom mechanism operates smoothly, and the focus ring is well-damped, allowing for precision adjustments. However, the lens hood could feel a bit flimsy compared to the rest of the build quality, which might not inspire the most confidence during handling.

Optical Performance

In terms of optical quality, the Canon EF 17-40mm f/4.0L delivers impressive sharpness across most of its zoom range. At 17mm, you may notice some slight softening in the corners, but stopping down to f/8 improves corner sharpness significantly. Chromatic aberration is also very well controlled, making this lens suitable for capturing high-contrast scenes without excessive fringing.

The lens features a circular aperture with 7 blades, allowing for pleasing bokeh, although the f/4 aperture does limit low light performance compared to faster alternatives. Overall, the lens delivers remarkable color rendition and contrast, which is often a hallmark of L series lenses.

Autofocus Performance

The EF 17-40mm f/4.0L is equipped with Canon's USM (Ultrasonic Motor) technology, providing fast and near-silent autofocus. This is a significant advantage for shooting in quieter environments or for capturing fleeting moments. The lens also has a full-time manual override feature, enabling you to quickly adjust the focus if needed without switching modes.

Compatibility

This lens is designed for Canon's EF mount, making it compatible with a wide range of Canon DSLRs. However, users of Canon's mirrorless systems will need to consider an adapter, which might result in slight changes in handling and performance.

Pros and Cons

Pros

• Excellent build quality with weather sealing.
• Good sharpness and contrast, particularly in the center.
• Fast and silent autofocus performance.
• Versatile focal range ideal for landscapes and architecture.

Cons

• Limited performance in very low light due to f/4 maximum aperture.
• Slightly soft corners at 17mm, improving significantly at f/8.
• The lens hood feels less robust compared to the lens itself.

Verdict

The Canon EF 17-40mm f/4.0L USM is an outstanding choice for those seeking a durable, high-quality ultra-wide zoom lens. While it has some minor drawbacks, such as limited low-light performance and occasional corner softness, its advantages—like excellent build quality, impressive optical performance, and reliable autofocus—make it a valuable addition to any Canon photographer's kit. Whether you're capturing sweeping landscapes or architectural marvels, this lens will not disappoint.