For the money, a full-frame lens that is quite impressive. For those just getting started in sports or wildlife photography, the zoom ratio makes this an excellent, simple-to-use option, and its tiny size and light weight make it convenient to carry everywhere.
Example Pictures for the Canon RF 100-400mm F5.6-8 IS USM
There are many other lens alternatives available from independent manufacturers if you have an RF-EF mount adapter. The Sigma 150-600mm is one option for individuals who need a lot of reach; however, it is substantially longer and has a wider maximum aperture at the zoom end, albeit with a little more vignetting at large apertures (approximately £150/ $150/ AU $ 300 extra).
There are options if you want to shoot using the built-in RF mount. For instance, you may choose the RF 600mm F11 IS STM (about £860/$699/AU $1,219) or the RF 800mm F11 IS STM (around £1,100/$1,000/AU $1,500) if you don’t want a zoom lens. Remember that both of these lenses have a fixed f/11 aperture in addition to the lack of a zoom, making them possibly less suitable for beginning photographers. In addition to being somewhat longer and brighter than the RF 100-400, the Canon RF 100-500mm F4.5-7.1 L I USM is also weather sealed, however it costs roughly £2,000 / $2,000 / AU $3,000 (about) more. If you’re feeling flush, you can get it for that price instead.
RF 100-400mm: Imatest (Opens in a new window)
Software was used in the lab to perform tests utilizing the 100-400mm lens and the 45MP EOS R5. The optical performance is good wide open, with decent performance through much of the frame and moderate softness at the borders throughout its zoom range. The resolution near the center (4,100 lines) is superb.
For the sharpest results when working in bright situations, narrow the f-stop a little bit more. With 100mm f/8, central resolution achieves exceptional results (4,600 lines), and as you travel off-center, it degrades to very good results (3,700 lines). We tested the lens at 100mm, 250mm, and 400mm focal lengths to see how the image quality held up when zoomed in. Nevertheless, keep in mind that since the maximum aperture decreases as you zoom, you obtain clearer details at 400mm f/11 than at 400mm f/8.
Color fringing, or lateral chromatic aberration, appears in uncorrected Raw photos but is unimportant when working with JPG files. The false color is easily corrected by raw processing software; in Adobe Lightroom Classic, you only need to make sure the Remove Chromatic Aberration option is selected. A small amount of pincushion distortion and a light vignette at the widest aperture are also eliminated by Canon’s JPG adjustments. Canon’s in-camera corrections are matched by an Adobe one-click Raw correction profile. Even with a small aperture, telephoto lenses can blur the background behind objects in their field of view. The 100-400mm lens produces beautiful background bokeh with soft-edged, rounded highlights for the most part. When using the lens with its aperture wide open, some cat’s eye highlights are visible at the borders of the frame, but when you stop it down, the rounded 9-blade diaphragm produces circular highlights across the frame.
Autofocus and Handling
Three distinct control rings—zoom, focus, and function—as well as control switches to select the focus mode and activate optical stabilization are included with the RF 100-400mm. The function ring is plain polycarbonate with a diamond-textured design, while the zoom and focus rings feature a rubber covering with raised ridges.
The inner barrel may be moved in or out by turning the zoom ring, which only needs a tiny bit of torque. It’s wonderful that the focal length is stable after it’s been adjusted and that the inner barrel doesn’t automatically extend lower. When engaged, a zoom lock switch maintains the lens’s smallest 100mm focal length.
Autofocus is powered by a silent USM focus motor. With the EOS R5, the lens quickly switches between close-up and distant focus and is swift enough to follow moving targets. There is also the option of manual focus, with both linear and nonlinear responses available. The RF 100-400mm is a good choice for videographers as well because it doesn’t show any obvious focus breathing, allowing you to achieve excellent focus photos without any distracting changes to the angle of view.
I use the control ring as an EV control, but you might find it more handy to switch between several focus modes, alter the aperture, or precisely adjust white balance. You can always tell how much of an adjustment you make since it clicks as it spins. For a cost of $79.99, you can have the ring switched to silent, click-free operation at a Canon servicing location.
As they are designed for distant things rather than up close ones, long lenses sometimes forgo their macro capabilities. The RF 100-400mm’s close-focus capability, which allows for a respectable 1:2.4 life-size magnification rating, extends to 3.4 feet (1 m).
Moreover, the lens has image stabilization, which is advantageous if used with an EOS R or RP model without IBIS. For these models, Canon rates the lens for around 5.5 stops of correction, and for IBIS versions like the EOS R5, 6.0 stops. I was able to take sharp 400mm handheld shots on the R5 at shutter speeds as slow as 1/4-second, and with great care, I even managed to get several sharp 1/2-second exposures.
Given the small aperture, strong stabilization is essential. The 100-400mm is best suited for shooting outside at f/8 when zoomed in; for images in dimmer artificial light, you must use a higher ISO or a longer shutter speed. The stability in this instance is sufficient to make subject motion more of a worry than a handshake.
To acquire a little bit more zoom power, you can add a teleconverter. The lens becomes a 140-560mm F8-11 with the TC 1.4x and a 200-800mm F11-16 with the TC 2.0x. A teleconverter is an expensive lens accessory that operates best in strong lighting conditions, costing between $500 and $600.