Canon RF 100mm F2.8 L Macro IS USM Lens Review

Well over two years into the existence of the Canon RF Lens series, the lineup remained devoid of what I consider a true macro lens, one that reached a full 1.0x maximum magnification. Sure, there were RF 35mm and 85mm lenses with enough magnification capabilities to achieve the word "Macro" in their names. While the 0.5x magnification those lenses produce is quite beneficial, macro photography is much more exciting at 1.0x, a 1:1 reproduction ratio — and beyond. The Canon RF 100mm F2.8 L Macro IS USM Lens brings is that "beyond" feature.

Canon's lens engineers indicated that RF lenses would have a smaller size, lighter weight, or new features with image quality, minimally, as good as the equivalent EF-series lens. In this case, the referenced EF predecessor lens is the 100mm f/2.8L IS USM Macro, and taking the maximum magnification spec up to an impressive 1.4x easily qualifies for the RF lens's new feature aspect. At review time, among the mirrorless camera manufacturer brands (Canon, Sony, Nikon, Sigma, and I'll add Tamron into the mix), the only full frame lens exceeding 1.0x without extension tubes or extenders is the special-purpose Canon MP-E 65mm 1-5x Macro Lens.

The 1.4x maximum magnification is not the only new feature on the Canon RF 100mm F2.8 L Macro IS USM Lens. See the new SA ring? I'll discuss this ring in much more detail later in the review, but in short, the spherical aberration control ring enables the bokeh (referring to the foreground and background blur) strength and quality to be adjusted.

With L-series optical and build quality, the RF 100 macro delivers outstanding image quality and high-grade image stabilization and autofocus performance from a well-constructed, weather-sealed package. Especially great is that this world is filled with perfect subjects for this lens, promising many opportunities for creating beautiful images.

Focal Length

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Focal length decisions should be made based on the perspective and subject framing desired. How far do you want to be from the subject, and what juxtaposition between the elements in the frame is desired? If tight framing with a longer subject distance is preferred, a longer focal length is needed, and the opposite is also true.

One of the primary uses for a 100mm lens is portraiture. I know, this is a "macro" lens, but it excels at all of the normal uses for a 100mm lens, especially portraiture. The 100mm focal length provides a great perspective for all types of portraits, especially for individual portraits ranging from moderately tightly cropped headshots to as widely framed as you have working space for. With adequate working distance, small group and family portraits are even within this lens's capabilities. A 100mm lens with a close focusing capability is a great choice for weddings, capturing details of a dress one minute, portraits the next, and photos of the rings moments later without a lens change required.

While many sports are best captured with long focal length lenses, not all require such, and you may find a 100mm lens ideal for some sports. The 100mm focal length (like most others) can be successfully used for landscape photography. A 100mm lens also works well for commercial and general studio photography applications, along with a wide range of other uses too numerous to mention.

While the 100mm focal length general uses list is long, adding macro focusing capabilities dramatically extends the usefulness of this lens. Macro lenses are available in a variety of focal lengths, but I find that the 90-105mm range is usually ideal for general-purpose macro photography.

One of this lens's superpowers is its 1.40x maximum magnification. As already mentioned, this macro capability exceeds that of most other lenses, and a large number of photographers are going to purchase this lens specifically for this feature.

Relevant to the focal length discussion is the working distance provided by this focal length at or over 1.0x magnification. The longer the focal length, the more working distance is available, and the less likely that little living creatures such as (insects) will be frightened away before or while being photographed. In this regard, 100mm is average for the available macro lens focal lengths, with the difference between 100mm and 90mm or 105mm being insignificant for most practical purposes. Those chasing insects and using a full-frame camera might prefer a longer focal length (perhaps 150mm or 180mm), and those working with mid-sized products at close distances may prefer a wider focal length macro lens (perhaps 35mm or 50mm). Otherwise, and in general, 100mm is likely just right for your macro photography needs.

Additional focal length considerations especially relevant to macro photography are how much of the background is visible at a given working distance (the angle of view strongly influences this) and how that background is rendered via compression and magnification — the strength of the blur. I'll talk more about the RF 100 macro lens's ability to blur the background soon, but once again, the 100mm focal length is average for the macro lenses available in all comparable mounts. With 100mm in use, more background is in the frame and the background is less blurred than when using focal lengths such as 150mm and 180mm, but 100mm provides considerably less background and significantly more background blur than wider focal lengths such as that of the Canon RF 35mm F1.8mm F1.8 IS STM Macro Lens.

Really cool is that, with a macro lens in hand, nearly everything on the planet becomes a potential subject. Here are some 100mm macro lens sample pictures (captured with different lenses).

Great little macro subjects abound – they are everywhere.

Insects, spiders, plants, food and candy, coins, jewelry, craft items, and commercial products – the list goes indefinitely. Bringing home flowers for your spouse may help them better enjoy (support) your macro photography pursuits, and they will likely appreciate prints of the results adorning your walls.

Simply walking around outside of your house will surely turn up interesting things to focus on.

Focusing your mind on the incredible details of nature is a great way to relax.

OK, not everyone will find a dark fishing spider carrying babies relaxing, but the details of even spiders are amazing.

Butterflies. Everyone loves butterflies. These images were captured with this RF lens.

Critical for such an image is the eye in sharp focus, but photography is not all about sharp results. Alternatively, this lens lets you get creative with color blur.

A focal length comparison is helpful to understanding a lens's angle of view.

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When used on an ASP-C camera model, the 1.6x FOVCF (Field of View Crop Factor) sensor format will see an angle of view similar to a full-frame-mounted 160mm lens. This angle of view forces a longer working distance that increases the depth of field, including more of the subject and background in focus. The APS-C angle of view favors tight portraits vs. full body framing (unless a considerable working distance is available).

Max Aperture

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While an f/2.8 aperture is not especially wide for prime lenses around this focal length, f/2.8 is common for the macro prime lenses, and f/2.8 is a relatively wide (fast) aperture among lenses in general.

With an f/2.8 aperture, this lens is handholdable and capable of stopping action in relatively low light levels without resorting to noisy-high ISO settings. The f/2.8 aperture provides adequate light for AF to perform well in low light conditions.

Combine an ultra-short minimum focusing distance with the short telephoto 100mm focal length and the background can be blurred into obscurity. While there are times when everything in the frame should be in focus, most macro portrait subjects look great set against a creamy background blur, free of distracting elements. This lens, with a closely positioned subject and the f/2.8 aperture selected, permit such a strong, subject-isolating background blur.

While talking about the available apertures of a macro lens, it should be mentioned that at close focusing distances, the effective max aperture decreases. The following chart details the measured (metered) light loss incurred at the specified subject magnification.

Magnification:	∞	0.3x	0.6x	1x	1.4x
Exposure Factor (loss in stops)	0	1	1 1/3	2	2 1/3
Effective Aperture	f/2.8	f/4	f/4.5	f/5.6	f/6.3

If using auto exposure, the camera will automatically account for the varying amount of light. If using a manual exposure, adjusting the exposure becomes your responsibility. This attribute is not unique to Canon or any other brand macro lens. Still, it is annoying to dial in manual exposure, change focusing distances, and realize that your settings are no longer appropriate for the task.

Circling back to the f/2.8 aperture, this modest opening at 100mm avoids two of the wide aperture disadvantages, large size and heavy weight. The smaller and lighter aspects of the Canon RF 100mm F2.8 L Macro IS USM Lens substantially increase its fun factor.

Here is an aperture comparison:

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The f/2.8 example, with a subject still well beyond this lens's minimum focus distance, shows the background being erased by the blur. I'll skip the usual maximum background blur example as there is only smooth color in that image.

When you move in close, DOF (Depth of Field) becomes shallow at wide apertures, and at macro subject distances, DOF becomes shallow at even narrow apertures. Careful camera alignment is essential to place the plane of focus on the desired subject parts (such as the wings of a butterfly) even at f/8 and f/11 when near or over 1.00x magnification.

Spherical Aberration Control

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A focal length longer than 100mm is often able to create a stronger background blur UNLESS the 100mm lens has spherical aberration control, an exciting (for some) new feature on the Canon RF 100mm F2.8 L Macro IS USM Lens. While the SA control is not equally effective over the entire focus distance range, the adjustment can significantly affect the bokeh, creating soft foreground and background defocus effects. As the aperture narrows, the effects are rapidly reduced (similar to native spherical aberration often found in wide-aperture prime lenses).

Note that this lens does not utilize an apodization filter as the Canon RF 85mm F1.2 L USM DS Lens but instead moves a floating lens element to adjust the effects.

Focus Distance (Magnification)	∞	5m	1m	0.38m (0.5x)	0.28m (1.0x)	0.26m (1.4x)
Variable Amount of SA	±2mm	±2mm	±4mm	±4mm	±0.5mm	±0mm

The variable amount refers to the length up to the intersection of the optical axis and the light ray shifted due to the spherical aberration, with reference to the position where the light ray converges on the optical axis during normal shooting in the 0 position. Right, that was a challenging statement to understand. Just know that the SA control feature adjusts the quality and strength of the foreground and background blur, and the amount of adjustment available varies somewhat over the focus distance range. Expect optimal utilization of the SA control ring to require some acclimation, with the EVF live view aiding greatly in the optimization.

Let's review some examples captured at f/2.8, the aperture showing the maximum effect. Here are the full images reduced in size:

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The SA Control Ring is continuously variable, with a light click stop at the zero position and a switch to lock the ring into that position. The above and below examples utilized the min, max, and zero'd positions, with a pair of examples taken from the mid position on each side.

In the above example, the background blur created at the zero position appears nice. Turn the ring to the max negative end, and the background appears even stronger and more impressive in character. Most photographers utilizing the SA Control Ring are going to favor the negative adjustment, as the positive direction imparts harsh bokeh.

As seen in the above images, the effective focal length changes as the ring is turned.

For most, the downside of the SA control feature is seen in the 50% crops shown below. These examples are from the center of the frame. The lens was autofocused on the flower for each of the images.

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In this closer look, we see that the zero SA ring position delivers a sharp subject and a attractive background blur. The SA Control Ring dials in an obvious soft focus effect. The background is rendered beautifully smooth with negative adjustment, and it is rendered harshly with a positive adjustment. The soft focus effect is not always welcomed, so the photographer must decide when to utilize this capability. Portraits are a favorite use of soft focus.

Impressively, the R5 test camera has no trouble autofocusing the lens with even full SA adjustment selected. However, your ability to precisely manually focus with SA control dialed in will be quite challenged. As the subject will not be rendered sharp with a strong SA adjustment, high precision focusing matters little.

Here are 50% crops extracted from the periphery of the image circle and showing background blur:

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The SA adjustment affects the periphery of the frame similar to the center of the frame, as desired.

Image Stabilization

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The longer the focal length, the larger subject details (captured at the same distance) are rendered, and the more still the camera must be held to avoid subject details crossing imaging sensor pixels, the cause of motion blur. While 100mm is not an especially long focal length, this lens is able to be used at extremely close focus distances, which also enlarges the subject details, increasing the camera stability requirement.

Image stabilization is an extremely valuable feature in any lens and an especially valuable one in a macro lens. Further aiding this assistance is this lens's Hybrid Image Stabilization, adding another dimension of stabilization over conventional IS. Hybrid IS corrects for shift movement to the conventional angular correction, as the graphic below depicts.

The Canon RF 100mm F2.8 L Macro IS USM Lens's image stabilization is rated at 5 stops of shake correction, a significant advantage.

Additionally aiding handheld assistance is coordinated image stabilization. When used on Canon mirrorless cameras featuring IBIS (In Body Image Stabilization), starting with the EOS R5 and EOS R6, coordinated IS raises the assistance rating to an incredible 8-stops. A specific advantage of the coordinated camera and lens image stabilization is the ability to reduce rotational movement.

Note that image stabilization becomes less effective at close focus distances. Assistance is still provided at short distances, but the amount of assistance is modestly reduced.

Expect substantial shake correction from this lens's IS system. On a rather shaking day, under ideal conditions, with a fully-handheld ultra-high-resolution EOS R5 behind it, the RF 100mm macro lens rendered nearly all images sharp at 1/6 second, most sharp at 1/5 second, and enough 0.5-second exposures were sharp to be worth attempting.

The RF 100mm macro lens does not feature selectable IS modes, but the IS system automatically detects and corrects for panning motion.

Canon builds excellent image stabilization systems, and the RF 100's image stabilization system is well implemented. From a visual standpoint, the viewfinder image is still, and compositional adjustments occurring smoothly, an especially important feature for macro photography. When the lens is held motionless, scene drifting is sometimes apparent. From an audibility standpoint, expect nothing to be heard unless an ear is close to the lens.

An image stabilization benefit that should not be overlooked is the aid in AF precision. The camera's AF system can produce better focus precision if the image it sees is stabilized. Canon has indicated that this is true even with a subject that is in motion and being photographed with action-stopping shutter speeds. With the 100mm f/2.8 combination producing a shallow depth of field at the close focus distances this lens is capable of, AF precision is especially critical.

Image stabilization does not stop subject motion, but it is incredibly effective at stopping camera shake for both stills and video. When you need/want to leave the tripod behind, IS is there for you, helping to ensure sharp images and adding significant versatility to this lens.

Image Quality

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Everyone loves a sharp lens. Macro-capable prime lenses tend to be especially pleasing in this regard, and testing a sharp, single focal length lens should be a quick task. Shoot a few test sets, rave about the results, and move on. That expediency didn't happen.

The results from the standard lab image quality tests are good. The Canon RF 100mm F2.8 L Macro IS USM shows itself a sharp lens, delivering outstanding contrast and resolution, even at f/2.8, from the center of the frame deep into the corners.

While the center of the frame results are not quite the best ever from a Canon lens, they are quite sharp, with little improvement showing when stopped down. Most lenses are sharper when stopped down one or two stops, but this one's test chart results break that norm.

Most lenses are not as sharp in the corners as in the center, but this one mostly breaks that mold also, delivering remarkable peripheral image quality. The RF 100 is so sharp in the periphery at f/2.8 that little or no improvement is seen at narrower apertures (aside from peripheral shading clearing), again breaking the norm. Even the absolute corner of the test chart is rendered remarkably sharp at f/2.8 by this lens.

Taking the testing to scenes with depth illuminated some complications. We next look at many test sets of center-of-the-frame 100% resolution crop examples. These images were captured using an ultra-high resolution Canon EOS R5, with RAW files processed in Canon's Digital Photo Professional (DPP). The Standard Picture Style was selected, with sharpness at 1 on a 0-10 scale. Note that images from most cameras require some level of sharpening, but too-high sharpness settings are destructive to image details and hide the deficiencies of a lens.

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A key to analyzing these results is to find details in the plane of sharp focus at the widest aperture. Especially key to analyzing the results from this lens is to watch that plane move rearward as the aperture is closed.

In the first set of results, captured at an infinity focus distance, the entire samples are ideally sharp in every frame (after accounting for some haze and heatwave distortion). All looks great in this sample set.

You have heard of a worker bee, right? This is a slacker bee. The bee included in the second set of results kindly sat still long enough for me to capture a few sets of sample images.

For that second set of images, the lens was switch to MF immediately after autofocusing on the bumblebee. In the f/2.8 sample, the eye, front antenna, front leg, and other details on this plane are sharp, as desired. In the f/4 sample, the plane of sharp focus has moved to the back antenna and abdomen. Even by f/8, increased depth of field has not recovered the front antenna sharpness seen at f/2.8. If I had captured an additional sample at f/11, you would see that recovery mostly occurring.

Focus shift, the plane of sharp focus moving forward or backward as the aperture is narrowed (residual spherical aberration or RSA), if it exists, is often made apparent in such comparisons. While many modern lenses automatically correct for focus shift, this one does not.

The focus shift issue with the RF 100 affects both MF and AF (with the SA control ring in the 0 position). Canon cameras autofocus with the aperture wide open, not accounting for the stopped down depth of field or resulting plane of sharp focus, and I couldn’t tell the difference in my MF vs. AF results.

Compensating for the focus shift requires focusing in front of a subject. Pressing the depth of field preview button shows the shifted focus, but the lens does not focus (on the R5 at least) while the DOF button is pressed. This anomaly from an RF L-series lens is disappointing.

Basically, focus shift is not a concern at f/2.8 or f/11, and focus shift is not an issue at longer focus distances.

The third set of center results, featuring the red berry, seem to show that the strength of this anomaly is not entirely consistent.

The mushroom results further illuminate the undesired focus shift effect.

For sanity purposes, I tested Canon's previous 100mm macro lens, the EF 100mm f/2.8L IS USM Macro, for focus shift. That lens does not exhibit this issue.

Did I get a bad copy of the Canon RF 100mm F2.8 L Macro IS USM Lens? My guess was no. Supporting that theory was a technical rep confirming the issue with his lens, and the test results shared above were forwarded to the Canon lens team in Japan.

Still, I wasn't able to accept this issue without personally testing a second lens. Here are the results from lens #2:

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First, determine where the sharpest focus is in the f/2.8 image, somewhere near the center of the top of the letter "V". This is what the AF system and your manual focusing would normally select.

Next, select the f/4 result, and again find the sharpest focus, which is now to the left of the top of the letter "I". The f/5.6 and f/8 examples continue to exhibit focus shift. With an R5 behind this lens, the f/11 result is beginning to show some diffraction softening. Still, f/11 is frequently used for macro photography, and the f/11 result shows the original point of sharp focus coming back into the depth of field. However, little depth of field is provided in the front of the point of focus.

So, as illustrated above, the focus shift is obvious. Will it matter in real life? Absolutely. Here is that example:

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The f/2.8 and f/11 samples are sharp, but the others are not.

Will the Canon RF 100mm F2.8 L Macro IS USM Lens focus shift matter on a lower resolution camera, such as the 20 MP Canon EOS R6? Cameras with higher resolution imaging sensors, such as the 45 MP EOS R5, make lens issues more apparent. I don't have an R6 to test with, but reducing the R5 images to 67% (square root of 20/45) simulates the difference (though the over-sampling should be an advantage). In that set of results, the difference remained noticeable. However, some modest additional sharpening brings those f/4 through f/8 results up to reasonable sharpness. The camera's default settings oversharpen results, and it is possible that some less critical R6 owners will not notice the impact of the focus shift issue.

The RF 100 macro lens's focus shift is apparent over most of the image circle, but it diminishes deep in the corners.

The response from Canon's optical engineers was to confirm that, due to its 1.4x magnification (1.4:1 reproduction ratio) capability, a magnification far exceeding 1.0x, the RF 100mm F2.8 L Macro IS Lens's optical design exhibits some focus shift.

The focus shift is not sample dependent and is not related to the SA control ring. As focus shift is characteristic of this lens, no production changes to the lens or lens/camera firmware updates are anticipated. Correction, when necessary, is accomplished by focusing slightly in front of the subject.

Next, we'll look at a comparison showing 100% extreme corner crops captured and processed identically to the above center-of-the-frame images. The lens was manually focused in the corner of the frame to capture these images. The first results are from the bottom-left, the next is from the bottom-right, and the last set is from the top-left.

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Samples taken from the outer extreme of the image circle, full-frame corners, can be counted on to show a lens's weakest performance. This lens produces sharp corner results wide open and outstanding results by f/5.6.

Does corner sharpness matter? Sometimes it does, sometimes it doesn't. This lens provides that feature when needed.

When used on a camera that utilizes a lens's entire image circle, peripheral shading is expected at the widest aperture settings. The approximately 2.7 stops of corner shading at f/2.8 will be noticeable in some images. Especially images with out-of-focus corners and a close focus distance, as is common with macro photography, hide this shading as illustrated in the f/2.8 sample below.

Stop down to f/4, and just over one stop of shading remains. By f/11, under half a stop remains.

APS-C format cameras, should they become available with an RF mount or adapter facilitating such, using lenses projecting a full-frame-sized image circle avoid most vignetting problems. In this case, the just-over one-stop of shading showing at f/2.8 may be visible in some images, especially those with a solid color (such as a blue sky) showing in the corners.

One-stop of shading is often used as the visibility number, though subject details provide a widely varying amount of vignetting discernibility. Vignetting is correctable during post-processing with increased noise in the brightened areas being the penalty, or it can be embraced, using the effect to draw the viewer's eye to the center of the frame. Study the pattern showing in our vignetting test tool to determine how your images will be affected.

Lateral (or transverse) CA (Chromatic Aberration) refers to colors of the spectrum being magnified differently. Lateral CA shows as color fringing along lines of strong contrast running tangential (meridional, right angles to radii) with the mid and especially the periphery of the image circle showing the most significant amount as this is where the most significant difference in the magnification of wavelengths typically exists.

With the right lens profile and software, lateral CA is often easily correctable (often in the camera) by radially shifting the colors to coincide. However, it is always better to avoid this aberration in the first place.

Color misalignment can easily be seen in the site's image quality tool, but let's also look at a worst-case example. The image below is a 100% crop from the extreme top left corner of a Canon EOS R5 frame showing diagonal black and white lines.

There should only be black and white colors in these images, with the additional colors in this sample indicating a mild amount of lateral CA. While there is some color separation showing here, the amount of separation is modest.

A relatively common lens aberration is axial (longitudinal, bokeh) CA, which causes non-coinciding focal planes of the various wavelengths of light. More simply, different colors of light are focused to different depths. Spherical aberration along with spherochromatism, or a change in the amount of spherical aberration with respect to color (looks quite similar to axial chromatic aberration but is hazier) are other common lens aberrations to observe. Axial CA remains somewhat persistent when stopping down, with the color misalignment effect increasing with defocusing. The spherical aberration color halo shows little size change as the lens is defocused, and stopping down one to two stops generally removes this aberration.

In the real world, lens defects do not exist in isolation, with spherical aberration and spherochromatism generally found, at least to some degree, along with axial CA. These combine to create a less sharp, hazy-appearing image quality at the widest apertures.

The examples below look at the defocused specular highlights' fringing colors in the foreground vs. the background. The lens has introduced any fringing color differences from the neutrally-colored subjects.

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The color separation at f/2.8 is somewhat noticeable, with improvements showing at narrower apertures.

Bright light reflecting off of lens elements' surfaces may cause flare and ghosting, resulting in reduced contrast and sometimes interesting, usually destructive visual artifacts. The shape, intensity, and position of the flare in an image are variable, dependant on the position and nature of the light source (or sources), selected aperture, shape of the aperture blades, and quantity and quality of the lens elements and their coatings. Canon utilizes Super Spectra Coating to combat flare, but the moderately high 17 element count is not helpful in this regard. In our standard flare test results, I see good flare and ghosting resistance, including at narrow apertures.

Flare effects can be embraced or avoided, or removal can be attempted. Removal is sometimes challenging. High flare resistance is a welcomed trait of this lens.

Two lens aberrations are particularly evident when shooting images of stars, mainly because bright points of light against a dark background make them easier to see. Coma occurs when light rays from a point of light spread out from that point instead of being refocused as a point on the sensor. Coma is absent in the center of the frame, gets worse toward the edges/corners, and generally appears as a comet-like or triangular tail of light which can be oriented either away from the center of the frame (external coma) or toward the center of the frame (internal coma). Coma clears as the aperture is narrowed. Astigmatism is seen as points of light spreading into a line, either sagittal (radiating from the center of the image) or meridional (tangential, perpendicular to sagittal). Remember that Lateral CA is another aberration apparent in the corners.

The image below is a 100% crop taken from the bottom-right corner of an R5 frame.

That is impressive performance, confirming this lens's outstanding optical quality into the periphery of the image circle.

In our standard geometric distortion test, this lens shows a minuscule amount of pincushion distortion. The amount is low enough that you will likely never notice it.

Most modern lenses have lens correction profiles available (including in-camera), and distortion can easily be removed using these. Still, geometric distortion correction requires stretching which is detrimental to image quality.

As seen earlier in the review, the amount of blur a lens can produce is easy to illustrate, and telephoto macro lenses are especially advantaged in this regard. Due to the infinite number of variables present among all available scenes, assessing the bokeh quality is considerably more challenging. Here are some f/11 (for diaphragm blade interaction) examples.

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The first set of examples shows defocused highlights. These shapes are beautifully smoothly filled, with the outside starting to become polygonal by f/11 (normal). The last three examples are full images reduced in size and looking great.

Except for a small number of specialty lenses, the wide aperture bokeh in the frame's corner does not produce round defocused highlights, with these effects taking on a cat's eye shape due to a form of mechanical vignetting. If you look through a tube at an angle, similar to the light reaching the frame's corner, the shape is not round, and that is the shape seen here.

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As the aperture narrows, the entrance pupil size is reduced, and the mechanical vignetting absolves with the shapes becoming rounder.

A 9-blade count diaphragm will create 18 point sunstars from point light sources captured with a narrow aperture. In general, the more a lens is stopped down, the larger and better-shaped the sunstars tend to be. Despite this lens having a relatively wide max aperture, requiring the diaphragm blades to be substantially closed to create a small opening, the sunstars it produces are not especially big in size. Still, the shapes are decent.

The example above was captured at f/16.

Here is the Canon RF 100mm F2.8 L Macro IS USM Lens design diagram:

Dealing with abnormalities significantly extends the time required to complete a lens review. This one, upon discovery of the focus shift issue, took a long detour, including testing of a second lens. While that issue is significant for some, the other optical properties of this lens are, overall, remarkable. The Canon RF 100mm F2.8 L Macro IS USM Lens is capable of producing jaw-dropping imagery.

Focusing

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Like the Canon RF 70-200mm F2.8 and RF 70-200mm F4, the RF 100 F2.8 Macro gets an advanced, high-performing AF system driven by dual Nano USM (Ultrasonic) focus motors.

Canon U.S.A.'s Rudy Winston states: "Canon's new Nano USM technology uses a completely different form factor, but achieves focus results within the lens via the same principles of ultrasonic vibration energy, transmitted here into linear (rather than rotational) movement within the lens. This tiny new Ultrasonic motor achieves the combination of fast, near-instant response during still image shooting, with the smoothness required for good focus during video recording."

Nano USM acts as an ultra-fast version of STM AF, combining the benefits of a high-speed Ring USM actuator with an STM system stepping motor's quiet and smooth, direct, lead screw-type drive system. Like Ring USM driven AF systems, Nano USM focuses extremely fast – nearly instantly. Like STM AF systems, Nano USM focuses almost silently, with only faint clicks and shuffling being audible. Also, like the other Nano USM lenses, this one focuses smoothly.

Ring USM was Canon's former choice for high-end lens AF systems. While most Ring USM lenses are fast and accurate performers, they generally do not focus smoothly in Movie Servo AF and produce considerably more focus chatter. Nano USM (and STM) lenses autofocus markedly smoother and quieter than Ring USM lenses.

Of utmost importance is AF accuracy, and from that perspective, all of the Nano USM-driven AF systems to date have performed impressively. With macro focusing distance capabilities, the RF 100 provides new challenges to the AF system. Still, the accuracy performance has been good.

Wide aperture lenses are optimal for low light AF, and with a moderately wide f/2.8 aperture, this lens can autofocus in a dark environment. As always, AF is slower in low light. Still, this lens still gets the job done even under light levels difficult to see in.

The RF 100mm macro lens features a focus distance range limit switch that, in addition to enabling the full focus distance range, allows distance selection to be limited to 0.85 — 1.64' (0.26 — 0.50m) and 1.6' (0.50m) — ∞. The narrower ranges potentially decrease focus lock times via reduced hunting.

Normal is for the composition to change size in the frame (sometimes significantly) as focus is pulled from one extent to the other. This is referred to as focus breathing, a change in focal length resulting from a change in focus distance. Focus breathing negatively impacts photographers intending to use focus stacking techniques, videographers pulling focus, and anyone critically framing while adjusting focus.

This lens produces a moderately strong change in subject size through full extent focus distance adjustment.

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The 0.3x represents the focus distance setting of a close-focusing non-macro lens.

The RF 100's ribbed rubber-covered focus ring is modestly sized and positioned snuggly in front of the SA ring, meaning that care is required to differentiate between the rings, especially with gloves. The smooth-turning manual focus ring provides a nice resistance, and adjustments remain solidly centered. What is not so smooth is the adjustment rate. A slight stepping behavior is noticeable and annoying when precisely manually focusing with the EVF or LCD fully zoomed.

Like STM, Nano USM utilizes a focus-by-wire, electrical manual focus design (vs. a direct gear-driven system), with the manual focus ring electronically controlling the lens's focus. FTM (Full Time Manual) focusing is supported in AF mode with the camera in One Shot Drive Mode, but the shutter release must be half-pressed for the focus ring to become active. Note that FTM does not work if electronic manual focusing after One Shot AF is disabled in the camera's menu. The lens's switch must be in the "MF" position and the camera meter must be on/awake for conventional manual focusing to be available.

With electronics driving AF, the rate of focus change imparted by the focus ring can be electronically controlled, and it can be variable based on the ring's rotation speed. I prefer a linear adjustment speed and have the camera configured for such. That said, linear is the only option provided by this lens. This ring provides approximately 500° rotation from MFD to infinity or vice versa. The rate of adjustment is ideal at close distances and a bit fast at long distances.

While the Canon RF 100mm F2.8 L Macro IS USM Lens does not focus a great deal closer than the EF predecessor, its 10.2" (260mm) minimum focus distance creates a substantially higher maximum magnification spec of 1.4x. Part of the difference likely stems from the reduced focus breathing that Canon promised from this RF lens.

Model	Min Focus Distance "(mm)		Max Magnification
Canon RF 35mm F1.8 IS STM Macro Lens	6.7	(170)	0.50x
Canon MP-E 65mm Macro Lens	9.4	(240)	5.00x
Canon RF 85mm F2 Macro IS STM Lens	13.8	(350)	0.50x
Canon RF 100mm F2.8 L Macro IS USM Lens	10.2	(260)	1.40x
Canon EF 100mm f/2.8L IS USM Macro Lens	11.8	(300)	1.00x
Canon EF 100mm f/2.8 USM Macro Lens	12.2	(310)	1.00x
Sony FE 90mm f/2.8 Macro G OSS Lens	11.0	(280)	1.00x

A subject measuring approximately 1.0 x 0.67" (25 x 17mm) fills a full-frame imaging sensor at this lens's minimum focus distance.

Is the difference between 1.4x and 1.0x noticeable? Absolutely. Here is that comparison.

Load Comparison Images

The minimum focus distance is measured from the imaging sensor plane with the balance of the camera and lens (and potentially lens hood) length taking their space out of the number to create the working distance. Without the hood installed, the RF 100 provides 4.3 (110mm) of working distance at 1x and 3.3" (85mm) at 1.4x. While working at these short distances, the lens hood will often shade the subject.

Need a shorter minimum focus distance and higher magnification? An extension tube mounted behind this lens should provide a significant decrease and increase, respectively. Extension tubes are hollow lens barrels that shift a lens farther from the camera, allowing shorter focusing distances at the expense of long-distance focusing. Electronic connections in extension tubes permit the lens and camera to communicate and otherwise function as normal. As of review time, Canon does not have RF mount-compatible extension tubes available, but third-party options are available.

This lens is not compatible with Canon extenders.

Build Quality & Features

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While Canon's RF L lenses take on a slightly updated look, those familiar with EF L lenses will immediately recognize this lens's heritage, denoted by the red ring. The L designation assures that this lens has professional-grade build quality and reliability required by those who must bring home the assigned imagery.

Load Comparison Images

The Canon RF 100mm F2.8 L Macro IS USM Lens looks great, featuring a smooth exterior diameter that is comfortable in hand. The barrel exterior is high-quality engineering plastic.

Three rings on a prime lens? That's what we get with this one. While the control ring is positioned far forward, as I mentioned before, the other two rings are close enough to require extra concentration to differentiate.

Canon's RF lenses feature a knurled "Control Ring," able to be configured for fast access to settings including aperture, ISO, and exposure compensation. Positioning this ring at the front of the lens is optimal for avoiding inadvertent use. Use the lens hood diameter transition to find the Control Ring fast. Note that the control ring is clicked by default, and this ring's clicks are audible in camera-based audio recordings. Canon offers a control ring click stop removal service (for a fee).

This lens's switches have a shallow profile. A slightly raised area around the two image stabilizer switches aids in tactilely differentiating these from the two AF-related controls. The superb switch design provides just enough raised surface in the center of each switch to make them easily usable, even with gloves on. Two of the three switches are easy-to-use two-position types, enabling the desired setting by fully sliding the switch. A little extra care is required to select the focus distance limit setting in this 3-position switch's center position. The switches firmly click into position, providing an assuring feeling from both positional and quality standpoints.

Note that changing the AF/MF switch setting opens and closes the aperture when the camera is powered off.

While not waterproof (water damage will void the warranty), this lens is dust and moisture-sealed and built for outdoor professional use in conditions that are not always favorable.

The front and rear elements are fluorine-coated, helping dust and water drops to shed off (or easily blow off) of the front and rear lens elements. Cleaning problematic issues, such as fingerprints, is considerably easier with fluorine coating, a difference especially appreciated in the field.

The RF 100 gained a small amount of weight and length over its EF counterpart (without a mount adapter factored in). Still, this lens has a comfortable size and weight for long-term handheld use.

Model	Weight oz(g)		Dimensions w/o Hood "(mm)		Filter	Year
Canon RF 24-70mm F2.8 L IS USM Lens	31.8	(900)	3.5 x 4.9	(88.5 x 125.7)	82	2019
Canon RF 35mm F1.8 IS STM Macro Lens	10.8	(305)	2.9 x 2.5	(74.4 x 62.8)	52	2018
Canon MP-E 65mm Macro Lens	25.8	(730)	3.2 x 3.9	(81.0 x 98.0)	58	1999
Canon RF 70-200mm F2.8 L IS USM Lens	37.8	(1070)	3.5 x 5.7	(89.9 x 146.0)	77	2019
Canon RF 85mm F2 Macro IS STM Lens	17.6	(500)	3.1 x 3.6	(78.0 x 90.5)	67	2020
Canon RF 100mm F2.8 L Macro IS USM Lens	25.8	(730)	3.2 x 5.8	(81.5 x 148.0)	67	2021
Canon EF 100mm f/2.8L IS USM Macro Lens	22.1	(625)	3.1 x 4.8	(77.7 x 123.0)	67	2009
Canon EF 100mm f/2.8 USM Macro Lens	21.2	(600)	3.1 x 4.7	(79.0 x 119.0)	58	2000
Sony FE 90mm f/2.8 Macro G OSS Lens	21.3	(602)	3.1 x 5.1	(79.0 x 130.5)	62	2015

For many more comparisons, review the complete Canon RF 100mm F2.8 L Macro IS USM Lens Specifications using the site's lens specifications tool.

Here is a visual comparison featuring a couple of Canon RF zoom lenses:

Positioned above from left to right are the following lenses:

Canon RF 24-70mm F2.8 L IS USM Lens
Canon RF 100mm F2.8 L Macro IS USM Lens
Canon RF 70-200mm F2.8 L IS USM Lens

The same lenses are shown below with their hoods in place.

Use the site's product image comparison tool to visually compare the Canon RF 100mm F2.8 L Macro IS USM Lens to other lenses.

The RF 100 L macro shares the EF 100 L macro's lens's 67mm filter thread size. 67mm threads are common, modest in size, and reasonable in price.

Canon's Macro Ring Lite flashes (such as the MR-14EX II) are compatible with the RF 100 L when using a Canon 67 Macrolite Adapter (and a 58mm lens cap).

A tripod mount ring is not included in the RF 100 L Macro Lens box. While this lens is not big or heavy, it is modestly front-heavy when the camera is tripod mounted.

The EF lens variant had a Canon Tripod Ring D optionally available. I added this accessory to my EF lens as soon as it became available, never removed it, and came to value it greatly. The mount ring permits the camera and lens weight to be balanced over the tripod head, making framing adjustment (less tendency to sag) and camera rotation easier.

When I saw the first product images for the RF lens version, I did not see the traditional tripod mount ring grove and was concerned that this accessory would not be available. However, this is not a traditional lens, and three unique indents are provided in the location where a tripod ring would be mounted. A later-received image clarified the purpose of these indents and putting the mount ring availability concern to rest.

The Tripod Mount Ring and Adapter E(B) (B is for black) features an adapter, an inner piece that fits over the lens, anchors in the little slots, and is held in place by the ring over it. The adapter facilitates the ring's attachment and rotation. The E ring takes on a design similar to that of other recent RF lenses, including the Canon RF 70-200mm F2.8 L IS USM Lens. The ring is a useful accessory.

The Canon ET-73C lens hood is included in the box.

This semi-rigid plastic round-shaped hood has a ribbed interior designed to avoid reflections. The hood offers a strong amount of protection from both impact and from bright light. The push-button release makes hood installation and removal easy.

Canon always includes a case in L-series lens boxes, and the Lens Pouch LP1222 is in this one. While the pouch protects against scratches and dust, only the bottom is padded against impact. For increased protection, consider a Lowepro Lens Case or Think Tank Photo Lens Case Duo for a quality, affordable single-lens storage, transport, and carry solution.

Every lens comes with front and mount caps, but especially the front cap sees a lot of use, and Canon's current caps are excellent.

Price, Value, Compatibility

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Not long before the Canon RF 100mm F2.8 L Macro IS USM Lens was introduced, the price of the Canon EF 100mm f/2.8L IS USM Macro Lens increased a substantial amount. Despite asking, I was provided no reason for the increase. In hindsight, a good reason for the EF lens price increase would be to make the RF 100mm Macro Lens's even modestly higher price appear more reasonable.

While the RF 100 is an outstanding lens in most regards and one that will see a great deal of use, the price is relatively high. Adaptable Sigma and Tamron lenses delivering good image quality at considerably lower prices make the RF lens's price harder to justify.

As an "RF" lens, the Canon RF 100mm F2.8 L Macro IS USM Lens is compatible with all Canon EOS R-series cameras. Canon USA provides a 1-year limited warranty.

The reviewed Canon RF 100mm F2.8 L Macro IS USM Lens was purchased online-retail.

Alternatives

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When looking for lenses to compare with the Canon RF 100mm F2.8 L Macro IS USM Lens, the EF predecessor, the Canon EF 100mm f/2.8L IS USM Macro Lens, seems the obvious choice.

In the image quality comparison at f/2.8, the RF and EF lenses show similar performance in the center of the frame, but the RF lens nicely outperforms its counterpart in the periphery. Stop down to f/4, and the EF lens takes a slight center of the frame advantage, while the RF lens continues to hold the peripheral advantage. At f/5.6, the lenses become mostly optically equalized. That the EF lens does not exhibit focus shift is a strong advantage. The RF lens has modestly more peripheral shading at wide apertures and slightly more at narrow apertures.

The Canon RF 100mm F2.8 L Macro IS USM Lens vs. Canon EF 100mm f/2.8L IS USM Macro Lens comparison shows the RF lens slightly heavier and slightly longer. However, that comparison is without consideration for the Mount Adapter required on the Canon EOS R-series cameras the RF lens is compatible with. Add the adapter, and the differences evaporate.

The RF lens drops the focus distance window (I don't miss these on the mirrorless camera format as the EVF provides this feature), reduces the focus ring size, adds a better image stabilization system, adds a control ring, and adds an SA control ring. A big difference between these two lenses is the RF lens's 1.4x magnification capability vs. 1.0x. The RF lens starts out with a modestly higher price. Again, the mount adapter cost erases that difference (if it is not already in the kit).

Use the site's comparison tools to create additional comparisons.

Summary

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I consider a telephoto macro lens to be a mandatory part of my kit and always include the best available option. What is the best Canon macro lens? Focus shift aside, the Canon RF 100mm F2.8 L Macro IS USM Lens is that lens.

I didn't see the focus shift issue coming, and this issue is my primary complaint with this lens. Precise focusing is especially important with a macro lens, and when apparent, focus shift causes this lens fall below that expectation. Again, I see no issues at f/2.8 or f/11 and narrower and high resolution imaging sensors make the issue more visible. Focus slightly in front of the subject if focus shift becomes an issue.

Relating to focusing is a minor complaint. Perhaps I'm too perfectionistic, but I want the focus ring on my macro lens to adjust the distance smoothly, not in little steps.

Soft focus isn't my thing, so I'll not likely benefit from the Spherical Aberration Control Ring. That this feature is not my thing does not mean it shouldn't be yours. Your clients may love some soft focus portraits included in their portfolio, and this SA control adds versatility to the lens.

With an extremely fast, high-performing AF system and an advanced image stabilization system, this professional-grade lens is capable of delivering outstanding image quality, optically outperforming all Canon macro lenses prior introduced. The up-to-1.4x magnification capability especially takes close-up imagery to a new level.

So many interesting available subjects combined with this lens's extra-high magnification capability make the Canon RF 100mm F2.8 L Macro IS USM Lens a super fun option to have in the kit.