Canon mirrorless system owners have a few options when it comes to a standard zoom lens for an R series mirrorless camera. The RF 24-105mm F4 L IS USM ($1,299) is a midrange option, with a dimmer f-stop and shorter zoom range than the premium RF 24-70mm F2.8 L IS USM ($2,299) and RF 28-70mm F2 L USM, but notably better optics than the RF 24-105mm F4-7.1 L IS STM or RF 24-240mm F4-6.3 IS USM. Photos are sharp, even on high-resolution sensors, and while it's bigger than the F4-7.1 edition, it balances well on an R mirrorless body. If you want more range than the 24-70mm F2.8, or just want to spend a bit less, the 24-105mm F4 fits the bill.
More Than a Kit Zoom
The term "kit zoom" is almost a dirty word in photographic circles, despite manufacturers largely offering much better starter options for SLRs and mirrorless systems in recent years than they used to. The RF 24-105mm f/4L IS USM is built, and priced, beyond even modern kit lens quality.
It offers more zoom range than the Nikon Z 24-70mm f/4 S (priced around $600 when bought with a camera) and is in a different class compared with Sony's FE 28-70mm f/3.5-5.6 OSS, which goes for about $400 on its own or $200 when bundled with a camera. Canon's low-cost RF 24-105mm F4-7.1 L IS STM is more in line with those lenses.
Canon bundles the RF 24-105mm F4 L IS USM with a few of its cameras, but not at a discount. Still, many photographers buying an EOS R5 or R6 camera will reach to it as a starter lens. It's more than up to the task.
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It bears Canon's L designation, reserved for its top-tier products, and lives up to the moniker. The barrel is polycarbonate, and internal seals prevent dust and splashes of water from intruding. It's about the same size as similar lenses for other systems, coming in at 4.2 by 3.3 inches (HD) and 1.5 pounds.
The barrel does telescope when zooming, roughly doubling its length at the 105mm position when compared with 24mm. The front element supports 77mm filters and a reversible lens hood is included, as are front and rear caps.
There's one quirk with the rear caps, and it's not only an issue with the 24-105mm, it also shows up with other RF lenses. Typically putting a rear cap on a lens only takes a simple twist, but with the RF lenses you need to take care to properly line up the rear cap and the lens. There's a small notch on the cap, at the 12 o'clock position, that must be lined up with a red dash on the mount. Photographers are used to lining up a lens properly before mounting it to a camera, but will now have to learn to do the same when putting the rear cap on a lens.
In addition to the normal array of anti-reflective materials, the front and rear element are also coated with fluorine. The compound repels grease and moisture, so you can more easily wipe away water droplets and fingerprints from the exposed glass. It's becoming more and more common, and while it's not something I expect to see in every lens, I'm happy it's included here.
There are three control rings. You get the normal zoom and manual focus controls, as well as a programmable control ring. The control ring has detents, so you can easily dial in small adjustments, and while the focus ring is electronic, it has a linear response—focus adjustments are based on how far you turn it, not how quickly. It's an important feature for video users, as it allows you to set start and end points for focus racks.
The zoom ring has set marks at the 24, 35, 50, 70, 85, and 105mm positions. There is a locking switch; it keeps the lens set at its shortest, 24mm position, so the barrel won't creep out and extend if you're carrying the camera at your side or around your neck. There are also switches to change focus modes (AF/MF) and to toggle the optical image stabilization system.
The first-generation EOS R and entry-level EOS RP cameras don't offer in-body image stabilization (IBIS), but newer models do. The RF 24-105mm delivers stabilized results with any camera thanks to its own optical system, and works in conjunction with newer cameras with stabilized sensors for long exposures and smooth handheld video.
The lens isn't billed as a macro, but has a very good close focus capability. It can hone in on subjects as close as 17.7 inches (0.45-meter), which is good enough for 1:4.2 life-size reproduction at the closest focus distance and maximum zoom. Typically we want to see a zoom lens offer at least 1:3 magnification power in order to call it a macro.
Benefits From Corrections
I tested the RF 24-105mm F4 with the 45MP EOS R5 and Imatest software. It's a sharp lens, even at f/4 and at the edges of the frame. Resolution is excellent at 24mm f/4 (4,000 lines), and while the edges aren't as sharp as the center, they're still good. Narrowing the aperture doesn't move the needle much on the average score, doing more to even out resolution across the frame.
There's a dip in wide open resolution at 50mm and 105mm, but results are very good. Stopping down to f/5.6 will get you sharper photos—the lens crosses the 4,000-line threshold that's considered excellent on the R5 there, and is just as good at f/8 and f/11.
Photos show less clarity at f/16 and f/22, the smallest available apertures. This is expected—light passing through the very narrow opening used at the smallest f-stops diffracts (or scatters, in layman's terms), which softens detail.
See How We Test Digital Cameras
In summary, the 24-105mm is solidly in the very good class at f/4, and improves to excellent from f/5.6 through around f/11. If resolution was all that mattered, there'd be very little to complain about with the lens.
We also look at distortion and uniformity of illumination. The lens does show a bit of barrel distortion at 24mm, 2.7 percent. It's enough to give photos with straight lines—think the horizon or architectural details—a very mild fish-eye bulge. It gives way to pincushion distortion as you zoom, which has the opposite effect. The lens shows about 1.5 percent at 50 and 75mm, and 1.7 percent at 105mm.
Canon cameras remove distortion automatically if you shoot in JPG format, and there's really no reason not to enable the correction if you don't want to deal with making manual software corrections to remove it. If you shoot in Raw format the distortion is easily removed, either with a manual adjustment or an Adobe lens profile.
The lens also shows a vignette. As with distortion, the camera automatically applies some level of vignette correction when shooting in JPG—you can turn the feature off, but I wouldn't. Even with the correction there is darkening at the corners (-2.3EV) and sides (-1.4EV) at 24mm f/4. It's enough to notice visually in many images, but it's not nearly as strong as the uncorrected image, which shows a -5.6EV drop at the corners and -2.7EV at the sides of the frame. Raw photographers will likely want to brighten them, at least partially. The same Lightroom profile that removes distortion also corrects for the vignette.
The vignette lessens as you narrow the aperture at 24mm, but never really goes away. It does lessen by the time you've zoomed to 50mm—the automatic corrections all but eliminate it at f/4, and the uncorrected image shows a noticeable -2.3EV drop, easily fixed in Lightroom. At narrower apertures the vignette isn't noticeable, even without correction. Results are very similar at 75mm.
We see a little bit of darkening at the corners in corrected 105mm f/4 images, but just about -1.2EV. The uncorrected shot shows -3.7EV, which is more noticeable, although it may add a bit of a natural frame for portraits. It drops to -2EV at f/5.6 and is negligible at smaller f-stops.
I wouldn't fret at all about distortion—correcting it can slightly narrow your angle of view, but it's not worth complaining about. If you're working at a lower ISO, the vignette corrections won't introduce too much additional noise to photos, but do remember that pushing the exposure at the corners can add some grain at a higher ISO.
The Beginning of a Promising Lens System
The Canon RF 24-105mm F4 L IS USM is likely to be the first lens many EOS R owners purchase. For first-time Canon buyers intrigued by the R mirrorless system, it's a solid introduction—a well-made zoom with a very useful range, strong close-up capability, and sharp optics. It's not perfectly corrected for distortion, and doesn't have the head-turning f/2 design of the RF 28-70mm, but not everyone wants a three-pound, $3,000 lens as their everyday zoom.
If you're already a Canon SLR owner and are intrigued by the EOS R, you may also find yourself considering splurging for a native lens instead of using your existing glass via an adapter. If you already have a good zoom that covers the range, it's a tough pill to swallow.
Part of that is because Canon doesn't offer a discount when buying it with a camera. It's not alone—Sony also bundles its FE 24-105mm without a discount, and it's a little bit more expensive. If you're working with a strict budget, the $400 Canon RF 24-105mm F4-7.1 IS STM is a compelling alternative, and a solid choice if you make most of your photos under the sun.
But if you can afford it, and prefer a 24-105mm to a 24-70mm, the RF 24-105mm F4 L IS USM ticks all the boxes. Images show sharp detail and the lens is priced in line with other first-party options. It will no doubt remain a staple choice, even as Canon grows the RF system.
The Canon RF 24-105mm F4 L IS USM zooms a bit further than the 24-70mm F2.8, and while it gathers less light, it's a fine choice for photographers who prefer a bit extra zoom power.
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