Canon RF 15-35mm F2.8 L IS USM Lens Review

Ask any professional or serious amateur photographer to list their most important lenses and a wide-aperture, ultra-wide-angle zoom lens will likely be high on their list. The Canon RF 15-35mm F2.8 L IS USM Lens arguably meets that need better than any lens before it. Of the trio of f/2.8 zoom lenses oft referred to as the trinity of essential lenses for most pro and serious amateur kits, the RF 15-35 was the first to hit the streets with the Canon RF 24-70mm F2.8 L IS USM Standard Zoom Lens arriving a short time later and the Canon RF 70-200mm F2.8 L IS USM Telephoto Zoom Lens promised to arrive later in the same year.

During a conversation, Canon's engineers promised that all RF lenses would have advantages such as smaller size, lighter weight, and/or new features over the EF lens counterpart. In this case, we get an extra mm of focal length on the wide end (the difference is noticeable and welcomed) and we also get, for the first time in this lens class, image stabilization (5-stops) in an f/2.8 ultra-wide-angle Canon zoom lens. In the past, we had to choose either an f/2.8 lens without image stabilization or an f/4 lens with image stabilization and for many of us, that meant two lenses were needed to cover all commonly encountered scenarios.

Canon's engineers indicated that image quality, advantaged by new lens design opportunities made available by the optimized RF mount, would minimally be equivalent and often better. Canon's earliest RF mount lenses set the image quality bar high and this lens does not disappoint in that regard.

The RF 15-35's image quality is stellar, the Nano USM AF system is silent and fast, the L-series build quality promises to hold up to the rigors of constant use. Those features, along with the versatility that this lens provides, make the Canon RF 15-35mm F2.8 L IS USM Lens an ideal fit for a huge number of kits.

Focal Length Range

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One of the first reasons to buy a lens or to select a lens for use is because the focal length or focal length range meets the needs of the subject being photographed. Lenses containing an ultra-wide-angle zoom focal length range are extremely popular and for a good reason: there are a huge number of subjects best captured with this range.

Lenses in this category vary somewhat in their starting and stopping focal lengths but the 16-35mm range has been Canon's most standard and I find this range useful as a gauge for comparing the other options. In this case, the RF 15-35's 15mm wide end is slightly wider than 16mm. The angle of view difference 1mm in focal length makes is minuscule at telephoto focal lengths, but the angle of view difference between 15mm and 16mm is noticeable. Here is that comparison using the Canon EF 16-35mm f/2.8L III USM Lens for the 16mm image:

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This lens's 15mm focal length has a substantial advantage over the EF 16-35's 16mm option – I love it.

While grabbing the wide-angle visual comparison, I felt compelled to also check the other end to make sure nothing changed there. The RF 15-35's 35mm result is showing slightly less magnification than the EF 16-35 III's 35mm result, but the difference is so small that it will not be noticed in the field and overall, this lens essentially reaches the full 35mm I used for my lens class comparable.

When you cannot get any farther away from your subject but still need to get a wide area of view in the frame, you want an ultra-wide-angle lens. Better still is to be able to choose an ultra-wide-angle for perspective reasons. An ultra-wide-angle lens has the capability, via perspective, of making a foreground object (ideally something interesting or attractive such as a flower) appear large and emphasized in relation to a distant yet potentially in-focus background with a vast amount of background in the frame and with subjects in the background rendered relatively small. To the vast amount of background point, especially careful attention must be paid to ultra-wide-angle composition — hopefully the background is as attractive as the foreground. I generally find excellent ultra-wide compositions more challenging to create than normal or telephoto compositions, but when the right scene is found, ultra-wide results are tremendously rewarding.

When the sunset blew up overhead instead of to the west, even 15mm wasn't wide enough. After tilting up to capture the brilliantly colored sky, I tilted the camera down to catch the foreground rocks and sky color reflecting on the water and merged the two images later to create a panorama.

The foreground emphasis with background inclusion capability fits especially well with landscape photography and this entire focal length range is perfect for that use. Start looking for a beautiful patch of flowers in front of a large mountain range (perhaps with a lake between them for an additional layer of interest) to utilize the ultra-wide-angle concepts just discussed. Or zoom to 35mm to take in a smaller angle of view, keeping distant subjects (such as mountains) larger in the frame.

It was a 2-hour, 4-5-mile hike up to this mill. I could take any two lenses I wanted and I cared about my images. The Canon RF 15-35mm F2.8 L IS USM Lens made the cut.

Try using this lens with a wide-open aperture and a close subject, letting the background go out of focus and drawing more emphasis on the foreground subject.

The only-mildly-wide-angle 35mm long end of this focal length is easy to compose with. This ultra-popular focal length shows a natural perspective, allowing the viewer to feel part of the scene.

While a close-up wide-angle perspective can look amazing in a landscape scene, it is generally to be avoided when a person is the primary subject. What you do not (usually) want to appear large in the foreground of your ultra-wide composition is a person's nose. We do not typically look at a person from really close distances and if we do, that person becomes uncomfortable with us being in their personal space (and even more so when a camera is in hand). When we look at photos of people captured from close distances, certain body parts (usually the nose) start to look humorously (to some) large. Unique portrait perspectives can be fun, but this technique should not be overused as it quickly gets old. Get the telephoto lens out for your tightly-framed portraits.

However, that does not mean wide-angle focal lengths are not a good choice for photographing people. Simply move back and include people in a larger scene, creating environmental portraits. The 35mm focal length is a great choice for full-body portraits and this focal length range also nicely handles small up to large groups. Note that group photography requiring an ultra-wide-angle focal length to fit everyone in the frame often leaves those in the front row appearing considerably larger than those in the back row. Back up or move the subjects back to reduce the multi-row perspective issue.

The 15-35mm focal length range is the perfect option for the wide work at weddings, family gatherings, and at other events as well as for photojournalism and sports photography needs. This lens can also be used overhead, to photograph over crowds such as those arriving on-field after football games.

Many of the just-discussed uses happen at a venue that itself is worthy of being photographed. Wide-angles make interior spaces, from houses to vehicles, look large and allow for illustrative composition even when working space is limited. This focal length range is an important one for architecture.

When photographing architecture, a level camera is often desired to keep walls and the sides of buildings straight/vertical in the frame, avoiding converging lines. However, it is not always possible, affordable, or convenient to get the camera to a height that permits the desired framing with a level camera. This is especially common when photographing the exterior of buildings from ground level. A tilt-shift lens is the ideal choice for this situation, but an ultra-wide-angle lens can also get the job done. Simply set up the camera in a level position, zoom out until the building (or other subject) is contained in the frame, capture the image, and then crop whatever is not desired in the frame, typically at the bottom, during post-processing. Basically, having a lens that takes in wide-angles of view can circumvent the need for a tilt-shift lens (with resolution loss from the cropping being a downside) or pixel-level-destructive perspective correction.

Directly related to architecture photography is real estate photography and that use has us circling back to include the landscape capabilities of this focal length range. The landscape after dark, aptly described as nightscape, is a frequent use for the 15-35mm range.

This Milky Way image started out at 15mm, but distant city lights made the bottom left portion of the horizon too bright, so I cropped it modestly.

Count cityscapes on this lens's great uses list.

Do you like the looking upward into the woods with tree trunks converging into the center of the frame type of picture? This lens can do that. It is seldom that my pack does not have a lens covering at least most of this focal length range in it.

Here are examples of what this focal length range looks like:

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Utilizing a smaller portion of the image circle means that APS-C sensor format cameras see a narrower angle of view, with 1.6x being the multiplier (FOVCF) for Canon's lineup. There are currently no RF-mount APS-C format cameras available, but this lens will show a full-frame angle of view equivalent of 24-56mm should such a camera become available.

Videographers will find the 15-35mm focal length range equally useful as still photographers and this lens is, in many ways, optimized for video recording.

Max Aperture

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While many wide-angle needs call for a narrow aperture (such as landscape photography), there are definitely advantages to having a wide aperture available. With few exceptions, f/2.8 is the widest aperture currently available in full-frame zoom lenses of any focal length.

The f/2.8 aperture is one stop wider than the also-common f/4 lenses have available. The number "one" seems small, but the 2x difference in light it provides is not. Compared to an f/4 lens, an f/2.8 max-aperture lens can stop action in half as much light using the same ISO setting. Alternatively, a 1-stop lower ISO setting can be used in the same light level and the difference in noise can be significant at the higher settings. Photographing indoor sports, low light events, and the night sky are scenarios where this lens's aperture can be game-changing.

Another advantage held by wide apertures is their ability to strongly blur the background. Wide-angle lenses are not the most adept at creating strong background blurs, but the f/2.8 aperture is better at this than f/4.

The following images show the maximum background blur this lens can create.

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At 15mm with the lens focused at minimum focus distance, the distant background details remain quite recognizable. On the other hand, at 35mm, the background shows a nice amount of blur.

In a zoom lens, the max aperture will sometimes be stated as a range, indicating that the max aperture narrows as the focal length increases. A positive feature of this lens is that the max aperture is fixed, with f/2.8 always available. Manually-set wide open exposures can be retained and counted on throughout the entire zoom range.

Image Stabilization

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Having an f/2.8 aperture in a zoom lens is great, but also having image stabilization in the same lens is even better, adding greatly to the lens's versatility. Unless I am using a camera support, I seldom leave home without IS and I often regret those times when I do. While image stabilization does not stop subject motion, it allows handholding of the camera in extremely low light situations with still subjects (or permits motion blurring of subjects with sharp surroundings such as flowing water). The image quality difference made by IS is potentially dramatic.

One situation that I am frequently counting on IS for assistance with is when handholding in medium and low light levels when significant depth of field is needed, allowing narrower aperture use without a tripod. When using a circular polarizer filter with narrow apertures (typical for landscapes and cityscapes), IS can be helpful even under direct sunlight. I often find myself trail running while hiking with a camera and family/friends (that don't wait for me) and when I stop to shoot, I am frequently breathing hard and not steady. IS makes that work.

IS is useful for stabilizing the viewfinder, aiding in optimal composition (though not as big of an issue with wide-angle focal lengths). IS is also useful for video recording, helping viewers to avoid that motion sickness feeling.

Canon's image stabilization systems have improved dramatically since first introduced and this one is fantastic. IS makes a faint "hmmm" while active, audible only from about an inch or two from the lens. Canon's IS systems have long been well behaved, meaning that the viewfinder image does not jump and I do not find myself fighting against IS while recomposing or recording video. I have not noticed the image frame drifting while IS is active.

In addition to general refinements, this lens gets a very-high 5-stops of assistance rating. Improved communications between the lens and the camera via the new RF mount has made this impressive rating possible. For example, based on this rating, an ISO setting 5 stops higher, ISO 3200 instead of ISO 100 or ISO 25600 instead of ISO 800 for example, would be necessary to increase the shutter speed enough to compensate for the help provided by this system. That difference is huge in terms of image quality.

At 15mm, with the help of image stabilization, most of the 1.3-second handheld results were sharp and over 50% of the 1.6-second results were sharp. A solid percent of 35mm results were sharp at 0.8-seconds and over 50% were sharp at 1.3-seconds. Very impressive.

These numbers should be considered about the best I can do. While I'm not the steadiest photographer, testing is done under ideal conditions, indoors on a concrete floor. Quickly hike up a big mountain and shoot from an unstable position in strong winds and a significantly faster shutter speed is going to be needed. However, the amount of assistance should remain similar and that is important.

Image Quality

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When you buy a high-grade f/2.8 max aperture lens, you want great image quality at that wide aperture. In the not-too-distant-past, ultra-wide-angle zoom lenses showed good reason to stop down by one or two stops. Then came the Canon EF 16-35mm f/4L IS USM Lens and Canon EF 16-35mm f/2.8L III USM Lens, two extraordinary-performing models. As mentioned, the Canon designers promised me that all of the RF lenses would have advantages over their EF counterparts and that image quality would be (minimally) as good and often better and especially the Canon EF 16-35mm f/2.8L III had the bar set high.

I am happy to report that this lens rocks.

In the center of the frame, the Canon RF 15-35mm F2.8 L IS USM Lens turns in sharp results over the entire focal length range even with a wide-open f/2.8 aperture. The 28mm f/2.8 results from our our two review lenses are just slightly softer than the other focal lengths, but this focal length becomes similarly sharp as the rest at f/4. Otherwise, aside from a slight improvement shown at 24mm, you will be pressed to notice the difference in sharpness (resolution and contrast) brought about by f/4.

Especially at ultra-wide-angles, image quality typically degrades as the image circle's radius is traversed, meaning that corners are seldom rendered as crisply as the center of the frame. While I won't go as far as saying the corner performance equals the center performance in this case, the corners are rendered well, even at f/2.8. Stopping down slowly improves periphery performance but clearing peripheral shading yielding increasing contrast accounts for much of the improvement.

In addition to our standard lab tests, I like to share some real-world examples. The images below are 100% resolution center of the frame crops from images captured in RAW format using a Canon EOS R. The images were processed in Canon's Digital Photo Professional using the Standard Picture Style with sharpness set to "2" out of 10 (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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The EOS R's imaging sensor does not appear to be challenging this lens's performance. Details are being nicely resolved at f/2.8 and the results show little reason to stop down for resolution and contrast purposes.

This testing often illustrates a detrimental lens attribute referred to as focus shift, the plane of sharp focus moving forward or backward as the aperture is narrowed (residual spherical aberration or RSA). That is not an issue with this lens. Depth of field increases evenly in front of and behind the focused distance as the aperture narrows.

Next we'll look at a comparison showing 100% extreme top-left (first) and bottom-right (second) corner crops captured and processed identically to the above center-of-the-frame images. These images were manually focused in the corner of the frame.

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As this lens had the potential to be a great landscape lens, one of my favorite photography genres, and though optimistic, I was especially concerned with corner performance. The small details captured during landscape photography are unforgiving with the corners of the frame providing an especially big challenge to lens designers, and for this lens to be my next go-to landscape lens, the entire frame had to be sharp. It is that. Look at the small bud in the corner of the first example in each set. That is impressive performance, especially for a zoom lens with these focal lengths.

Corner sharpness does not always matter, but when it does matter, including for landscape photography, this lens delivers impressively.

As referenced, peripheral shading is present in RF 15-35mm Lens corners. This is normal and RF-mount lenses do not avoid this issue. At 15mm f/2.8, the nearly-5-stops of shading will not go unnoticed. Shading slowly decreases with focal length increase, but the nearly-4-stops of shading at 35mm will still be noticeable. Figure roughly 1 stop of peripheral shading reduction for each stop of aperture opening reduction. With over 2.5-stops of shading remaining in the corners at 15mm f/11, some vignetting correction may be needed for landscape and other images. The f/11 shading slowly decreases as the focal length increases, but there is still over a stop of shading in 35mm corners.

Should this lens ever be compatible with an APS-C format camera model, the smaller imaging sensor would avoid the peripherally-darkened areas of the image circle.

Vignetting can be corrected 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.

The effect of different colors of the spectrum being magnified differently is referred to as lateral (or transverse) CA (Chromatic Aberration). 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 greatest amount as this is where the greatest 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 though it is always better to not have the problem in the first place. Any color misalignment present can easily be seen in the site's image quality tool, but let's also look at a set of worst-case examples, 100% crops from the extreme top left corner of EOS R frames showing diagonal black and white lines.

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Most zoom lenses show obvious lateral CA present, especially at the full extents of their focal length range, and most zoom lenses have a short range of focal lengths in the middle that show little or no lateral CA. Very few zoom lenses show as little lateral CA over their entire range as this one does. At 15mm, modest color separation is showing, but the separation is negligible at the balance of the tested focal lengths. This is remarkable performance.

A relatively common lens aberration is axial (longitudinal, bokeh) CA, which causes non-coinciding focal planes of the various wavelengths of light, or 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 look for. Axial CA remains at least somewhat persistent when stopping down with the color misalignment effect increasing with defocusing while 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.

In the examples below, look at the fringing colors in the out of focus specular highlights created by the neutrally-colored subjects. Any color difference is being introduced by the lens.

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Again, these results are looking really nice.

On this lens, Canon's SWC (Subwavelength Structure Coating) along with ASC (Air Sphere Coating) are utilized to avoid flare and ghosting. Our standard flare test utilizes the sun in the corner of the frame (at 15mm, it is hard to avoid the sun or other bright light in the frame at times). At f/2.8, this test produces barely perceptible amounts of flaring effects. This test generally produces stronger flare effects at narrower apertures and some effects are showing in this lens's f/16 results but the amounts remain mild.

Flare effects can be embraced, avoided, or removal can be attempted. Removal is sometimes challenging and in those cases flare effects can be quite destructive to image quality.

There are two lens aberrations that 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). 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 images below are 100% crops taken from the extreme top-left corner of EOS R frames.

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Astrophotographers will notice that these results are among the best from any lens we have tested. While perfection is not being reached with some mild stretching of and horns attached to the corner stars, the effects are mild in comparison to many other lenses in this class.

Ultra-wide-angle zoom lenses typically have strong barrel distortion at the wide end, transitioning into negligible distortion a short zoom in, and pincushion distortion is typically found at the longer half of the range. While that description roughly holds up for the RF 15-35, the amount of barrel distortion at 15mm is remarkably low. By 20mm, a modest amount of pincushion distortion becomes visible and increases until moderate at 35mm.

Geometric distortion can make framing a scene with a straight horizon, such as the ocean, challenging as there are no lines parallel to the edges of the viewfinder or viewfinder gridlines. Cameras with electronic levels have a big advantage in overcoming this issue and in-camera lens aberration correction can render lines straight in an electronic viewfinder. Most modern lenses have lens correction profiles available for the popular image processing software and distortion can be easily removed using these, but geometric distortion correction requires stretching which is detrimental to image quality. Some portion of the image must be stretched or the overall pixel dimensions must be reduced.

The blur and quality of blur seen in the out of focus portions of an image are referred to as bokeh and while wide-angle lenses do not produce the strongest background blurs, this lens has attractive bokeh. Here are some f/8 examples (100% crops) of defocused specular highlights:

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The circles remain nicely rounded even with the aperture blades stopped down 3 stops and the centers are relatively evenly filled for this subject.

The images below are top-left 1/4 of the frame (1/4 of width and of height) crops further reduced. These images show the cat's eye bokeh caused by mechanical vignetting in the corners at f/2.8.

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The circles are no longer round in the corners, but this is normal. Stopping down restores the circular shapes.

As the aperture gets narrower, point light sources take on a starburst effect and in general, the wider the max aperture of the lens, the stronger the star effect a lens can produce. When stopped down, this lens's 9-blade aperture produces big, beautiful 18-point stars from point light sources.

The example above was captured at f/16 and the stars are even more sharply pointed at f/22.

The RF 15-35mm F2.8 L IS USM Lens design incorporates "3 aspheric lenses for high image quality from center to corner and 3 UD lenses to help reduce aberrations for minimized distortion." [Canon UK] This lens turns in impressive optical quality with rather strong peripheral shading and moderately strong distortion at the long end of the focal length range being remaining opportunities. The image sharpness will make most overlook those issues.

Focusing

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Unless manual focusing is being utilized, the combined performance of a camera and lens's autofocus system is critical to realizing the potential image quality of the combination. The Canon RF 15-35mm F2.8 L IS USM Lens receives a high-performing Nano USM (Ultrasonic Motor) driven AF system, technology first arriving in the L-series with the Canon RF 24-105mm F4 L IS USM Lens. This lens's AF system repeats the performance of that one.

Nano USM acts like 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 clicking heard with one's ear next to the lens. And, Nano USM lenses focus smoothly.

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."

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

Of ultimate importance is AF accuracy and from that perspective, the Canon RF 15-35mm F2.8 L IS USM Lens has performed impressively.

An f/2.8 zoom lens is often the first choice for photographing in low light environments, and with an EOS R5 behind it, the Canon RF 15-35mm F2.8 L IS USM Lens can lock focus on contrasty subjects under dark conditions.

The rubber-ribbed focus ring is mid-sized and positioned in front of the zoom ring (this is my strongly-preferred position).

Like STM, Nano USM utilizes a focus-by-wire or electrical manual focus design (vs. a direct gear-driven system). The manual focus ring electronically controls the focus of the lens. 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.

Electronically driven MF enables the rate of focus change to be variable based on the ring's rotation speed. I never acclimated to that feature and with the R-series cameras, a linear adjustment speed can be configured. That's my preference and in this mode, the RF 15-35 F2.8 L focus is adjusted slowly, with approximately 313° of ring rotation from MFD to infinity, for precise focusing capabilities.

The manual focus ring has an ideal resistance and adjustments are smooth and solidly centered with no unusual framing shift happening. Modest subject magnification/framing changes are seen in full extent focus range changes.

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This lens maintains (naturally or perhaps electronically) the proper focus distance (or close to it) throughout the entire zoom range (parfocal). Focus at 35mm and zoom out to 15mm with the image remaining sharp.

Cameras featuring Dual Pixel CMOS AF and Movie Servo AF make video recording easy and Nano USM lenses are well-suited for this task. The smooth focusing makes focus distance transitions easy on the viewer's eyes and the sound of the lens focusing is not picked up by the camera's mic. Even the lens's aperture changes are quiet and smooth.

No focus distance scale is provided on the lens, but a digital scale can be enabled in the electronic viewfinder or LCD.

The RF 15-35mm F2.8 L has an 11.0" (280mm) minimum focus distance that delivers a 0.21x maximum magnification at 35mm. Interesting is that this lens has the same minimum focus distance as the most recent EF 16-35mm lens yet has a modestly lower maximum magnification. The 0.21 maximum magnification spec is slightly better than that of many other brand lenses in this class and this number is high enough for the lens to be quite useful for close work.

Model	Min Focus Distance "(mm)		Max Magnification
Canon RF 10-20mm F4 L IS STM Lens	9.8	(250)	0.12x
Canon EF 11-24mm f/4L USM Lens	11.0	(280)	0.16x
Canon RF 14-35mm F4 L IS USM Lens	7.9	(200)	0.38x
Canon RF 15-35mm F2.8 L IS USM Lens	11.0	(280)	0.21x
Canon EF 16-35mm f/2.8L III USM Lens	11.0	(280)	0.25x
Canon EF 16-35mm f/4L IS USM Lens	11.0	(280)	0.23x
Canon EF 17-40mm f/4L USM Lens	11.0	(280)	0.25x
Canon RF 24-70mm F2.8 L IS USM Lens	8.3	(210)	0.30x
Nikon 14-24mm f/2.8G AF-S Lens	11.0	(280)	0.15x
Nikon Z 14-30mm f/4 S Lens	11.0	(280)	0.16x
Sigma 14-24mm f/2.8 DG HSM Art Lens	10.2	(260)	0.19x
Sony FE 16-35mm F2.8 GM II Lens	8.7	(221)	0.32x
Sony FE PZ 16-35mm F4 G Lens	11.0	(280)	0.23x
Tamron 15-30mm f/2.8 Di VC USD G2 Lens	11.0	(280)	0.20x
Tokina 16-28mm f/2.8 AT-X Pro FX Lens	11.0	(280)	0.19x

At 35mm, a subject measuring approximately 5.3 x 3.5" (135 x 89mm) will fill the frame at the minimum focus distance and a 12.1 x 8.0" (307 x 203mm) subject can fill the frame at 15mm.

The USPS love stamps shared above have an image area that measures 1.05 x 0.77" (26.67 x 19.558mm), and the overall individual stamp size is 1.19 x 0.91" (30.226 x 23.114mm).

Magnification from wide-angle lenses is generally significantly increased with the use of extension tubes which are, as their name implies, hollow tubes with electronic connections that shift a lens farther from the camera. This allows the lens to focus at closer distances, though long-distance focusing is sacrificed. As of review time, Canon does not offer RF mount-compatible extension tubes, but third-party options are available. Expect a shorter extension tube to work best with this lens.

This lens is not compatible with Canon extenders.

Build Quality & Features

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It's a member of the L lens series and that means this lens is designed for the high reliability and durability required by professional use. While these attributes are crucially important to professionals, a huge number of serious amateurs also recognize this importance.

Canon's RF L lenses have taken on a slightly updated look over the EF L models, but those familiar with EF L lenses will immediately recognize this lens's heritage, highlighted by the red ring. The RF L-series lens look and feel has now become firmly established and this lens fits that mold.

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With smooth external dimensions and tight tolerance between parts, the Canon RF 15-35mm F2.8 L IS USM Lens is comfortable to hold and a pleasure to use.

The rear-positioned zoom ring is ideally-located behind the focus ring. A slight diameter increase on the zoom ring, a design feature becoming common throughout the RF lens lineup, makes it easy to find. With the RF lenses gaining an additional ring and the rings consuming a significant percentage of the barrel, finding the right ring becomes modestly more complicated and tactile cues, especially this one, are helpful. With the zoom and focus rings located immediately adjacent to each other, finding this lens's manual focus ring without looking is not so easy.

The additional ring is the knurled "Control Ring", able to be configured for fast access to settings including aperture, ISO, and exposure compensation. A small amount of space is provided between the focus ring and the control ring, aiding in selection between the two. Note that the control ring is clicked by default and this ring's clicks are going to be audible in camera-based audio recordings. Canon offers a click stop removal service for this ring (at a cost).

This lens features a quality plastic external construction. As illustrated in some of the product images in this review, this lens extends slightly (0.53" / 13.4mm) when zoomed to 15mm. The extended inner lens barrel has a slight amount of play. An extension lock switch is not provided and was not needed on the test lens.

The AF/MF and IS switches are flush-mounted and low-profile, but just enough raised surface area is available for easy use, even with gloves. They snap crisply into place. Interesting is that changing the AF/MF switch position opens the lens aperture momentarily when the camera is powered off.

This is a weather-sealed lens, but don't confuse this feature with waterproofness. Still, weather sealing can sometimes save the day.

Like most other recent L lenses, the RF 15-35mm f/2.8 features fluorine coatings on the front and rear lens elements to avoid adhesion of dust and liquids and to make cleaning easier. This is one of those features that goes unnoticed ... until something happens in the field.

At 4.3 x 5.2" (108 x 132mm), this lens is beyond what most photographers would consider small and at 29.7 oz. (840g), this lens is beyond what most would consider light. Still, it is not too large or heavy to carry even for long periods of time and many miles. I packed it along with some other gear to Dream Lake in Rocky Mountain National Park four times during my 2+ weeks there and also hiked 4-5 miles with it to the Chrystal Mill in Marble, CO. where it spent much of the day on my back. Later, this lens went with me to Sky Pond, some other lakes on a well-over 10-hour hike, and many adventures since. Having this lens along was not a burden. And, the RF 15-35 is considerably lighter than some of the f/2.8 alternatives listed in the table below.

Model	Weight oz(g)		Dimensions w/o Hood "(mm)		Filter	Year
Canon RF 10-20mm F4 L IS STM Lens	20.1	(570)	3.3 x 4.4	(83.7 x 112.0)	n/a	2023
Canon EF 11-24mm f/4L USM Lens	41.7	(1180)	4.3 x 5.2	(108.0 x 132.0)		2015
Canon RF 14-35mm F4 L IS USM Lens	19.1	(540)	3.3 x 3.9	(84.1 x 99.8)	77	2021
Canon RF 15-35mm F2.8 L IS USM Lens	29.7	(840)	3.5 x 5.0	(88.5 x 126.8)	82	2019
Canon EF 16-35mm f/2.8L III USM Lens	27.9	(790)	3.5 x 5.0	(88.5 x 127.5)	82	2016
Canon EF 16-35mm f/4L IS USM Lens	21.7	(615)	3.3 x 4.4	(82.6 x 112.8)	77	2014
Canon EF 17-40mm f/4L USM Lens	16.8	(475)	3.3 x 3.8	(84.0 x 97.0)	77	2003
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
Nikon 14-24mm f/2.8G AF-S Lens	34.2	(969)	3.9 x 5.2	(98.0 x 131.5)		2007
Nikon Z 14-30mm f/4 S Lens	17.1	(485)	3.5 x 3.3	(89.0 x 85.0)	82	2019
Sigma 14-24mm f/2.8 DG HSM Art Lens	40.6	(1150)	3.8 x 5.3	(96.4 x 135.1)		2018
Sony FE 16-35mm F2.8 GM II Lens	19.3	(547)	3.5 x 4.4	(87.8 x 111.5)	82	2023
Sony FE 16-35mm F4 ZA OSS Lens	18.3	(518)	3.1 x 3.9	(78.0 x 98.5)	72	2014
Tamron 15-30mm f/2.8 Di VC USD G2 Lens	39.2	(1110)	3.9 x 5.7	(98.4 x 145.0)		2018
Tokina 16-28mm f/2.8 AT-X Pro FX Lens	33.5	(950)	3.5 x 5.2	(90.0 x 133.3)		2011

For many more comparisons, review the complete Canon RF 15-35mm F2.8 L IS USM Lens Specifications using the site's Lens Spec tool.

I always find a visual comparison helpful.

Positioned above from left to right are the following lenses:

Canon EF 17-40mm f/4L USM Lens
Canon EF 16-35mm f/4L IS USM Lens
Canon RF 15-35mm F2.8 L IS USM Lens
Canon EF 16-35mm f/2.8L III USM Lens

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

Remember that a Canon Mount Adapter EF-EOS R must be used to mount the EF lenses on an RF mount camera. Build your own comparisons using the site's product image comparison tool. I preloaded that link with another interesting comparison and many more lenses can be selected.

The Canon RF 15-35mm F2.8 L IS USM Lens accepts standard threaded 82mm front filters. While 82mm filters are rather large and priced a bit higher than smaller options, just having front filter threads is a big asset for a lens in this class, especially one reaching out to 15mm. As the 82mm size has become more common over the years, this size has also become one of the most readily available and it is shareable among a large number of lens models (including another member of the RF f/2.8 zoom lens trinity, the Canon RF 24-70mm F2.8 L IS USM Lens). Being rather large also means that this filter can be used on a large number of smaller filter-sized lenses using inexpensive step-up filter adapter rings.

Note that using a standard thickness circular polarizer filter on this lens will increase peripheral shading slightly. A slim model such as the Breakthrough Photography X4 is highly recommended.

The included, semi-rigid, petal-shaped hood is modestly-sized, yet it offers adequate protection from physical impact along with shading some light. The hood has a durable, easy-to-clean mold-ribbed plastic interior and a push-button release makes the bayonet mount easy to use. A petal-style hood is easier to align for installation (simply learn the petal orientation) while a rounded hood better enables the lens to stand on its hood.

As a rule, Canon includes a case with their L-series lenses and the RF 15-35 comes with the Canon LP1222 Lens Pouch. While the pouch protects against scratches and dust, only the bottom is padded against impact. Grab a Lowepro's Lens Case if single lens storage, transport, and carry is needed.

The lens cap design Canon is currently using is great.

Price, Value, Compatibility

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To get the best usually requires one to pay the most and within the Canon brand, this is the most expensive lens in its class. However, keeping everything in perspective is that the Sony FE 16-35mm f/2.8 GM Lens is only priced $100.00 less and that lens does not have 15mm or image stabilization. The price tag is not low, but professionals and serious amateurs should not have trouble justifying the cost.

As an "RF" lens, the Canon RF 15-35mm F2.8 L IS USM Lens is compatible with all Canon EOS R series cameras. Canon U.S.A. provides a 1-year limited warranty.

The reviewed Canon RF 15-35mm F2.8 L IS USM Lens was sourced from Canon U.S.A.

Alternatives

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The RF 15-35mm f/2.8 L lens will only mount on cameras with an RF mount, the R-series models. With the Canon Mount Adapter EF-EOS R behind them, adding modest size, weight, and cost, all of Canon's EF, TS-E, and MP-E lenses become compatible and that brings two impressive Canon ultra-wide-angle zoom lenses onto the alternatives list.

I'll start with the Canon EF 16-35mm f/2.8L III USM Lens. As discussed, this lens lacks the 5-stop image stabilization feature and 16mm is not as wide as 15mm.

In the image quality comparison, we see the two lenses competing closely. The EF lens is slightly sharper in the periphery at 16mm than the RF lens at the wider focal lengths, and the RF lens is slightly sharper at the longer end. Most are not going to find image sharpness a decision factor. The RF lens has less geometric distortion at the wide end and the EF lens shows less peripheral shading at 35mm and when stopped down.

Looking at the specs and measurements, the Canon RF 15-35mm F2.8 L IS USM Lens vs. Canon EF 16-35mm f/2.8L III USM Lens comparison shows the two lenses to be similar. The RF lens extends 0.53" (13.4mm) when zoomed to 15mm while the EF lens does not change size. The RF lens has a control ring. The RF lens features quieter Nano USM AF vs. the EF lens's Ring USM and the RF lens has a much longer focus ring rotation (313° vs. 105°). The EF lens has a higher maximum magnification spec of 0.25x vs. 0.21x. The EF lens has a modestly lower price, but factoring the adapter in reduces the difference a bit.

The other Canon ultra-wide-angle zoom lens I love is the Canon EF 16-35mm f/4L IS USM Lens. This EF lens gives up the f/2.8 aperture, a significant loss for stopping action including the night sky and for creating a blurred background. Again, 16mm is not as wide as 15mm.

In the image quality comparison, the two lenses produce similarly sharp images at the wide end, and the RF lens has the advantage at the long end. At f/4, the RF lens has less peripheral shading but the EF lens has less shading at narrower apertures. Expect the RF lens to create larger stars from bright light sources when a small aperture is used. The RF lens has less geometric distortion at the wide end and slightly more at the long end.

Looking at the specs and measurements, the Canon RF 15-35mm F2.8 L IS USM Lens vs. Canon EF 16-35mm f/4L IS USM Lens comparison shows the f/4 lens advantaged by lighter weight and smaller size. The RF lens extends 0.53" (13.4mm) when zoomed to 15mm while the EF lens does not change size. The RF lens has a control ring. The RF lens features quieter Nano USM AF vs. the EF lens's Ring USM and the RF lens has a much longer focus ring rotation (313° vs. 90°). The EF lens has a slightly higher maximum magnification spec of 0.23x vs. 0.21x. While both of these lenses have great performing image stabilization systems, the RF is rated for an additional stop (5 vs. 4) of assistance. The EF lens's much lower price is going to be a deciding factor for many.

Since the RF 15-35mm's introduction, two other high performing lenses worthy of consideration have been introduced. Check out the Canon RF 10-20mm F4 L IS STM and Canon RF 14-35mm F4 L IS USM reviews.

There are many other lenses that could be compared to the Canon RF 15-35mm F2.8 L IS USM Lens. Use the tools on this site to create your own comparisons.

Summary

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Add the Canon RF 15-35mm F2.8 L IS USM Lens to the growing list of reasons to get a Canon RF mount mirrorless interchangeable lens camera. This lens offers the complete package.

Always of utmost importance is image quality and this lens delivers excellence in this regard. Some peripheral shading and moderate pincushion distortion at the long end of the focal length range (your portrait clients may find this slimming) are the primary opportunities remaining. The incredible-performing image stabilization system will help realize impressive image quality even when shooting handheld.

The Nano USM AF system is fast (yet smooth), nearly silent, and most importantly, precisely accurate, ensuring the optimal image quality is achieved. The L-series build grade promises reliable service to those using their lenses daily and environmental sealing aids in that use outdoors. While not small or light, this lens is quite comfortable to use and the zoom and focus rings perform optimally.

The price tag is not low, but the value and versatility of this lens are high. The Canon RF 15-35mm F2.8 L IS USM Lens fills a key role in my kit.