Camnostic Review: Canon RF 100mm L Macro Beats EF Version, Others Handily

Which macro lens is the best for you depends a lot on what sort of macro work you do. For many of these use cases, the new RF 100mm f/2.8 L IS USM is going to be far and away the best for R mount shooters. We took it out into a field rife with wildflowers and insects within minutes of the UPS man coming and dropping it off yesterday evening. The upshot: it beats the EF version in across-the-frame sharpness, AF performance and handling.

Canon shooters back in the EF mount days were spoiled by the EF 100mm f/2.8 L lens, which was never surpassed over its long life. There were third parties that introduced innovative alternatives for other use cases, like the Laowa 24mm “snoot” lens designed for underwater shooting at a distance, and the Laowa 15mm f/4 macro. But for a general run-and-gun macro lens the Tamron, Sigma, Laowa and other brands never equaled the original – especially in sharpness and image stabilization. In fact, we believe best general macro lens in the Sony E mount and L mount ecosystems remains an adapted Canon EF 100mm L lens.

Sharpness:
On sharpness, the center of the frame isn’t noticeably better than the EF mount 100mm L lens, but the edges are night-and-day better on the new RF lens. This is consistent with what other reviewers have found, and Canon’s own MTF charts.

Autofocus:
What surprised us was how fast and confident the autofocus was. This is not something that will be obvious to people conducting indoor chart tests, but if you’ve snagged a bumble bee in tracking mode, it means the world. We shot the RF and EF lenses together at the same time on two R5 cameras, the EF mount version using Canon’s ring adapter. We were able to use object tracking to keep up with flitting insects on extremely busy backgrounds on the RF version, and the same task was next to hopeless on the EF version.

This leads to an interesting observation. Having used our trusty EF version for more than a year on R, RP, R5 and R6 bodies, it seemed that the new tracking system introduced with the R5 actually made the autofocus performance of the EF macro lens worse. Where the older R cameras seemed to have about the same autofocus as the 1DX and 5D Mark IV cameras, the newer RF mount models seemingly took a step backward. In retrospect, and in light of the RF 100mm f/2.8 L Macro lens performance, we believe this was due to a vastly more ambitious autofocus system that had autofocus speed demands that simply couldn’t be met by the EF version of the lens. Now that the RF version is much faster (roughly 3-4 times faster to rack focus) and more confident, tracking actually works. To confirm this theory, we turned tracking off and found that the EF lens did indeed work about as well as it used to with DLSRs.

Magnification:
That the new RF version can provide 40 percent more magnification versus the EF version is very significant for many users. These improvements really add up. With the R5 having more than two times the resolution of a 1DX, and the lens having 40 percent more magnification, with autofocus compensating for the greater difficulty in keeping things in focus for the run-and-gunners, and improved stabilization thrown in on top, the lens does feel twice as good in that use case.

Studio users won’t appreciate several of these factors. A great deal of macro users never use autofocus or stabilization, or shoot at maximum magnification. Aside from corner sharpness, many of those shooters may well be better off at the much-cheaper EF lens, a pristine copy of which can be picked up for $650 on the used market.

Downsides:
The lens does focus breath a little bit, where a focus pull of great distance will change the apparent magnification. This usually isn’t a big deal for stills shooters, but many macro shooters like to focus stack, and that’s problematic for them. Mitigating this is the fact that the amount of change in the angle of view is quite small. A landscape focus stacker would find it problematic, as those pulls can be quite large, but a macro shooter using a rack system likely won’t see a noticeable effect over the very short focus pulls needed in that use case.

Bryan Carnathan over at The-Digital-Picture.com did a fantastic review, as usual, and noticed focus shifting, which would be quite problematic for some types of shooters who need to use apertures between the ranges of f/2.8 and f/11. At the time of this writing we could not repeat that result ourselves with the copy we have, and we’ve reached out to Bryan to confer. [Update: We repeated tests with Bryan’s methodology after conferring and found that our copy does show a very small amount of focus shift, but not enough to make the focus plan move out from a focused point. Essentially, as the aperture was narrowed, the back of the focal plane receded, but the front of the focal plane kept up with the intended target due to the increased depth of field with the narrower aperture. The upshot: whether this is a noticeable issue may be copy-specific.]

Primary Use Case:
Like the EF version, this is a lens designed for the run-and-gunner – the macro shooter who may be shooting insects or flowers, etc. without a tripod, walking through a garden, forest or field. The focal length, stabilization, autofocus speed and other elements are clearly designed for this, where other macro lenses may lack them completely.

We took the two Canon lenses on a one-hour jaunt with an off camera flash, switching up to employing the same run-and-gun techniques, but at f/11, exploiting the artificial light. This has a “night garden” effect, with the flash overpowering the ambient light, to make backgrounds fade out to black. This is a useful technique for radically expanding the depth of focus, an otherwise short commodity in macro shooting.

This SA Control Silliness:
Much has been made of Canon’s introduction of the SA Control ring. Even Canon’s anointed ambassadors who had pre-release copies of this lens, who strived to say very nice things about all aspects of it, couldn’t actually produce an image that was apparently improved with the use of these settings. Trying it out, we could do no better. The best way to describe this feature is that it effectively introduces a frosted glass effect on the image that looks like it was applied in a 1990s image editing application. Someday, someone will produce an image that will have been improved by the application of that ring. In the meantime, one of the better features of the RF version is that it also has a switch that locks the SA Control ring, effectively rendering it harmless.