Canon RF 100-400mm f/5.6-8 IS USM Lens

The Canon RF 100‑400mm f/5.6‑8 IS USM Lens is a full‑frame telephoto zoom lens created for Canon’s EOS R mirrorless camera system. It delivers a powerful 100–400 mm zoom range, making it a versatile choice for wildlife, sports, travel, and everyday telephoto photography where subjects are at a distance. This lens stands out for offering significant reach in a compact and lightweight design, which makes it easier to use handheld compared to heavier professional telephoto optics.

Optically, the lens is constructed with 12 elements in 9 groups, including an Ultra‑Low Dispersion (UD) glass element and an aspherical element that help reduce chromatic aberrations and ensure clear, detailed images throughout the zoom range. Canon’s Super Spectra Coatings help suppress flare and ghosting, improving contrast and color accuracy even in bright or challenging lighting conditions.

Focusing performance is powered by Canon’s Nano USM (Ultrasonic Motor) system, which delivers fast, smooth, and near‑silent autofocus performance. This type of focus drive excels in both still photography and video recording, and the lens also supports full‑time manual focus override so you can fine‑tune focus without switching modes.

The lens includes optical image stabilization (IS) that provides up to 5.5 stops of shake correction on its own, based on CIPA standards. When combined with a compatible Canon camera that has In‑Body Image Stabilization (IBIS), this coordinated IS can deliver up to 6 stops of stabilization, helping to produce sharper handheld images at longer focal lengths.

A notable feature of this lens is its close‑focusing capability; at the 400 mm end, it achieves a maximum magnification ratio of 0.41x, enabling you to capture detailed close‑up images of subjects like flowers or small animals without needing a dedicated macro lens. The minimum focusing distance varies with focal length but can be as short as about 0.88 m (2.89 ft) at 200 mm, which is helpful when framing mid‑range subjects.

Despite its telephoto power, the RF 100‑400mm keeps overall dimensions manageable — measuring approximately 164.7 mm in length and weighing around 635 g (about 1.4 lbs). This “slimline” build makes it suitable for outdoor shooting and travel, where carrying bulky gear can be impractical. The lens also incorporates a 9‑blade circular diaphragm, contributing to pleasing background blur (bokeh) when shooting scenes with selective focus.

The lens’s front filter thread is 67 mm, enabling the use of commonly available filters like polarizers and neutral density (ND) filters without additional adapters. Additionally, the RF mount allows compatibility with Canon’s RF 1.4x and RF 2x extenders, extending the effective focal range to as much as 560 mm or 800 mm for situations demanding extra reach, such as distant wildlife or action photography.

Overall, the Canon RF 100‑400mm f/5.6‑8 IS USM merges telephoto versatility, solid optical performance, responsive autofocus, and excellent stabilization in a relatively compact package. It’s an appealing option for photographers who want substantial reach without the bulk of heavier pro lenses, and it’s especially well‑suited to outdoor and travel photographers seeking flexibility and portability.