Verdict

The RF 100-400mm becomes Canon’s most affordable telephoto zoom for the EOS R system without adapting an older EF lens. It covers a useful range that’s ideal for sports and wildlife, distant portraiture, as well as compressed landscape and urban views. The optical quality is excellent for the money with sharp results across the frame near and far, and at the maximum – albeit modest – apertures.

Canon’s kept the price, size and weight low by deploying a fairly dim f5.6-8 aperture which means you won’t achieve much blurring unless you’re very close to the subject and the background is very distant. Importantly for the target market, if you need a fast shutter to freeze any action, you’ll also need to be shooting in good light or be at peace using high ISOs. As a lower-priced lens, the RF 100-400 also lacks weather-sealing and a lens hood in the box, although Canon hasn’t skimped on focusing which is fast enough to capture fast action and impressively lacks any breathing. It also works with the RF teleconverters throughout the zoom range.

If you’re looking for a higher-end telephoto zoom, look no further than the RF 100-500 f4.5-7.1L or adapt the still superb EF 100-400 f4.5-5.6L Mark II. Both are L-series lenses with brighter apertures, sharper optics, weather-sealing, tripod feet and include lens hoods, but they’re larger, heavier and roughly four times the price. 

So while the RF 100-400 lacks their glamour, I’m pleased Canon’s producing a selection of more affordable, not to mention lighter, native RF lenses alongside its flagship L series. If you want even longer reach, also consider the RF 600 or 800mm f11 lenses. And while optically dimmer lenses used to raise alarm bells on older bodies, the latest cameras are comfortable focusing them in poor light, while high ISO quality improves with every generation. As such the RF 100-400 is easy to recommend if you want long-reach from a native RF zoom without breaking the bank or your back.