The shiniest and brightest lenses from the Canon RF range have started out with the release of the most common focal length zooms. One of these being the Canon RF 24-105mm f/4L IS USM. Considered more of a generalist lens than the Canon RF 24-70mm f/2.8L IS USM, the 24-105mm is an L-series offering and has a wider range of zoom which can fit everything from portraits to general landscapes.
On paper, this lens follows many of the workings of the regular DSLR version. But, is it solely just an RF version or has Canon added more treats into the basket?
Design
The Canon RF 24-105mm f/4L IS USM follows the same design as the other RF lenses, with a sparse barrel layout, but still very Canon L-series in appearance. The lens barrel is made out of polycarbonate and is fully weatherproofed with internal seals.
Inside the lens are 18 elements arranged in 14 groups, which include one UD glass and three aspherical elements. A Super Spectra coating has been applied to cut down on ghosting and flaring, a fluorine coating on the front element and the latest Nano USM autofocus motor added for good measure.
The aperture range goes from f/4-f/22, with a nine-blade rounded diaphragm and has a minimum focusing distance of 0.45m. There’s also the stabilization system, which claims up to five stops of compensation. A useful feature as the R and RF bodies don’t have this natively.
As the lens covers a good-sized focal range, it starts out at 107.3mm long and is 159mm when fully extended. Roughly 10mm shorter than the DSLR equivalent. The whole lens weighing in at 700g.
As mentioned earlier, Canon has kept to a simple design, which leaves out the regular distance scale and instead adds a third rotating ring. Closest to the camera body is the zoom ring, which is rubberized and ridged for easy gripping.
Next up is the manual focus ring, which has a slightly different texture and lastly the thinnest ring nearest the front of the lens can be configured to change things like exposure compensation and also clicks when rotated.
The lens barrel of the Canon RF 24-105mm f/4L IS USM has three switches, which cover AF/manual focus, on and off for the stabilization system and a lock switch to prevent the lens barrel from unnecessarily extending. The front of the lens also has a 77mm filter thread, each doesn’t rotate when extending and fits an EW-83N lens hood.
Initially, this is clearly an L-series lens with the same level of build quality even if it is classed as a more generic offering.
The Canon RF 24-105mm f/4L IS USM in Use
The new RF lenses now feature the Nano USM motor, which brings together the best bits of the USM and STM motors and should be quick and quiet enough for both the stills and video guys. In reality, the AF system reacts very quickly and quietly and works just as efficiently in all the AF modes. AI-Servo mode is the least reactive, but this is more down to the camera body than the lens itself. The results seem to be far better when the camera was in One-Shot AF mode.
When shooting video, the movement of the Canon RF 24-105mm f/4L IS USM is not picked up by the mic and there doesn’t seem to be any erratic movement. Manual focus is done by focus-by-wire, which means focusing is done electronically and works out to be very efficient in reality. In other words, this lens would be a great solution for the video guys.
With such a wide focal range on offer, it would be surprising for image quality to be outstanding throughout the range. But, surprisingly sharpness is at a high level from the widest to the most telephoto. Center sharpness is very good at 24mm at f/4 but hits it’s best from at f/5.6. Edge sharpness is slightly soft when the lens is wide open but starts to clear up by f/8.
In the middle of the range at 70mm, center sharpness is at its best at f/4, with edge sharpness at f/8. The telephoto end of the range is usually the least sharp, but everything cleans up at 105mm at f/5.6 and the edges are their most sharp at f/8.
In other words, this lens is a great overall performer at its widest aperture and depending on the focal length, only needs a little stopping down to get the sharpest results. Images at this point come out with a high degree of saturation and contrast and look equally well both at the wide and telephoto end of the range.
As for bokeh effects, f/4 lenses don’t always produce the smoothest and best-looking background blur, with the 24-105mm largely following suit. The nine-blade diaphragm does a reasonable job with color transitions, but there is a distinct onion effect on highlights in most cases. This means, especially for close-up subjects, bokeh is usable, but not the best out there.
The lens can also produce other anomalies such as vignetting, which is most apparent at 24mm wide-open, with 2.5 stops of light falloff. It’s not much less at 105mm, but when stopped down to f/5.6, the effect is much reduced and the least apparent at f/8.
Flare and ghosting are kept well in check, but chromatic aberration (CA) can crop up with different amounts, depending on the focal length. CA is actually quite low when the lens is wide open, reasonably low in the center of the range and has the worst performance at 105mm. This is most obviously seen in very high contrast areas.
The image stabilization system is a great benefit on an all-rounder lens such as this one. Five stops of compensation (four, in reality) come in very handy, especially at the telephoto end, allowing for some quite low shutter speeds. When Canon eventually implements image stabilization into their camera bodies, both lens and body will make for a great combo.
How Does the Canon RF 24-105mm f/4L IS USM Compare?
The whole RF lens range is still thin on the ground, which means the only real comparisons for the Canon RF 24-105mm f/4L IS USM are within the already released RF range. Thus we can’t bring you the regular comparison table.
However, there is some overlap with the RF 28-70mm f/2L USM, but the 28-70mm is aimed at a completely different market and costs a lot more. One other option could be using adapted EF lenses, which means the Canon EF 24-105mm f/4L IS II USM could be a possible alternative. Almost similar price tags, but the decision depends on if you want to go down the completely native RF route or not.
Conclusion
The original release price of the Canon RF 24-105mm f/4L IS USM has dropped a little, which means it’s more in line with the regular DSLR version. With fine optics and features, this makes the lens more attractive to swap over entirely to the mirrorless format.
The lens works out to be a great all-round performer and very consistent in sharpness levels. The addition of the new AF motor and image stabilization, adds to the appeal and the third barrel ring can be very useful for on the fly adjustments.
It does have a few caveats, like lateral chromatic aberration and average bokeh rendition. But, as the DLSR version has shown, the Canon RF 24-105mm f/4L IS USM is a great all in one lens, which is sure to be one of the mainstays of the mirrorless format for years to come.
