Canon RF 800mm F5.6 L IS USM Lens Review

The simultaneous announcement of the Canon RF 800mm F5.6 L IS USM Lens and Canon RF 1200mm F8 L IS USM Lens left the majority of Canon photographers wondering what Canon was thinking. Why were these two extreme lenses introduced in front of many missing mirrorless lenses? For example, RF 24mm f/1.4 and RF 35mm f/1.4 lenses remain unavailable.

Then we learned that the two new lenses shared the major design components with existing RF lenses. Specifically, the RF 400mm F2.8 L IS and the RF 600mm F4 L IS USM Lenses were used for the front of the new lenses.

"Inheriting the optical system of the "RF 400mm F2.8 L IS USM" that realizes light weight and high image quality at a high level, the optimum magnifying optical system is placed at the rear of the lens to extend the focal length." [Canon Japan, translated]

"Since it uses the same optical design in its front section as the EF400mm f/2.8L IS version III lens ..." [Canon USA]

When Canon introduced the RF 400mm F2.8 L IS USM Lens and the RF 600mm F4 L IS USM Lens, the primary change from the EF predecessor lenses was the integrated RF mount, along with a new wiring system. Introduction of the RF 800mm F5.6 L IS USM Lens and RF 1200mm F8 L IS USM Lens seemed a familiar scenario, this time with a 2x extender integrated into the back of the referenced RF 400 and RF 600 designs.

Is this the Canon RF 2x Extender? Looking at the specifications leads one to consider this possibility. The new lenses weighing slightly less and having the same number of elements and groups adds to this theory.

Model	Weight (lbs/)		Dimensions w/o Hood ("/)		Elements/Groups
Canon RF 400mm F2.8 L IS USM Lens	6.37	(2890)	6.4 x 14.4	(163.0 x 367.0)	17/13
Canon RF 400mm F2.8 L IS USM Lens + 2x	7.12	(3230)	6.4 x 15.9	(163.0 x 406.2)	26/18
Canon RF 800mm F5.6 L IS USM Lens	6.93	(3140)	6.4 x 17.0	(163.0 x 432.0)	26/18
Canon RF 800mm F5.6 L IS USM Lens + 1.4x	7.42	(3365)	6.4 x 17.8	(163.0 x 452.3)	33/22
Canon RF 600mm F4 L IS USM Lens	6.81	(3090)	6.6 x 18.6	(168.0 x 472.0)	17/13
Canon RF 600mm F4 L IS USM Lens + 2x	7.56	(3430)	6.6 x 20.1	(168.0 x 511.2)	26/18
Canon RF 1200mm F8 L IS USM Lens	7.37	(3340)	6.6 x 21.1	(168.0 x 537.0)	26/18

However, moving to the lens design diagram comparison clears up this misconception. While the new lenses feature a set of optics that double the focal length, the optics are new and optimized, including a UD (Ultra-low Dispersion) element, and shared between the two new lenses.

Note that the first and second sets of comparison images below are not sized to the same scale.

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The drop-in filter, part of the optical design, is moved behind the RF 800 and RF 1200's new integrated magnification optics. Also note that the new lenses are modestly longer than their counterparts with the RF 2x mounted.

That the based-on RF 400 and RF 600 optical designs are similar, relatively new, extremely high performing, and ultra-lightweight should be recognized.

What level of image quality should we expect from the RF 800 and RF 1200? We are accustomed to Canon's big white lenses delivering outstanding optical performance at their widest apertures and still decent performance with extenders mounted, minimally so with the 1.4x. However, the optical designs for these lenses incorporate a 2x extender, and that design element reduces the image quality expectation.

Here are the MTF charts in a comparison format, clarifying the optical expectations.

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The higher the lines on the chart, the better the lens is performing from an optical perspective. Black lines represent contrast, while blue lines represent resolution. Solid lines represent sagittal performance, while dashed lines show meridional performance.

The bottom line is that the RF 800 should not provide sharpness (contrast and resolution) close to the RF 400 without extenders, but it could be slightly sharper than the RF 400 and RF 2x combination. The same is true for the RF 1200 vs. RF 600, with the RF 1200 trailing the RF 800 slightly in optical performance.

The price tags on the RF 800 and RF 1200 lenses are extremely high, the highest prices ever for regular-production Canon autofocus lenses. Few will justify the above-illustrated small optical improvement for the additional $5,000.00 and $7,000.00 expenditure over the based-on lens, and Canon understands that these are low-volume lenses.

While the RF 800 F5.6 and RF 1200 F8 have a slight image quality advantage in the comparisons at their native focal length, the primary advantage of these lenses appears to be compatibility with RF 1.4x and 2x extenders that take the focal lengths to crazy-narrow angles of view. The RF 800 F5.6 extends to 1120mm f/8 and 1600mm f/11. The RF 1200mm F8 extends to 1680 f/11 and 2400mm f/16.

However, just OK optical performance magnified by an extender does not end well. In addition, f/11 image quality begins to be impacted by the softening effects of diffraction on higher resolution cameras, and f/16 will show a noticeable diffraction impact even on lower resolution cameras.

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These charts do not exude optimism in regard to the expected with-extender image quality.

Back to the "Why this lens?" question. Canon already has a broad range of EF lenses that perform superbly on the EOS R-series mirrorless cameras using the Canon Mount Adapter EF-EOS R. While there is an EF 800mm f/5.6 in the line-up, that lens is showing its age (and it is heavy).

The low friction design and manufacturing efficiencies of shared components undoubtedly influenced the decision to introduce these specific lens models.

What is the RF 800mm F5.6 L lens going to be used for? Outdoor sports, wildlife, and news photojournalism is that answer. During a conversation, Canon shared that the latest cameras' capabilities are making outstanding bird images considerably easier to capture, generating "off the charts" demand for bird photography lenses. These lenses target that need.

So, who is going to buy the RF 800 and RF 1200? If you do not need a focal length shorter than 800mm or 1200mm and have the financial resources to afford the longer lens, it makes sense to get the longer lens. That said, primarily institutions, professionals at the top of their game, and serious, well-funded amateurs will own these models.

Focal Length

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The primary reason to buy the RF 800 is the 800mm super-telephoto focal length. As of review time, the 800mm focal length is differentiating, otherwise achievable only with extender combinations (or the inexpensive Canon RF 800mm F11 IS STM Lens).

When you need to frame a subject tightly and can't get closer due to:

• Physical barriers (streams, cliffs, etc.)
• Legislated barriers (lines on a field, property boundaries, etc.)
• A subject that does not tolerate closer photographers (skittish birds, for example)
• Safety reasons (dangerous wildlife, high-speed vehicles, etc.)
• Stealth requirements (law enforcement mission, for example)
• Becoming a viewing obstruction (such as getting in front of spectators at a speaking event at a large venue)
• Laziness (sometimes relaxing is a joy of photography)

Then, you might need an 800mm lens.

If you simply don't want to get closer, including for comfort reasons or to avoid impacting wildlife behavior, an 800mm lens might be just right. Sit in the comfort of your car or house, avoid crossing a creek, stay back from the surf, stay out of view, etc.

This raccoon photo was taken from my sunroom.

When you want to capture a compressed look from a distant perspective, you might want an 800mm lens. When you want to create an extremely strong background blur, isolating a subject from even a busy and otherwise-distracting background, an 800mm lens might be what you need.

An 800mm lens is primarily useful for a small subject niche, primarily sports, photojournalism, and wildlife.

Watch for this lens in use at events, including the Olympics, Super Bowl, World Cup, NASCAR races, and many other major sporting events. Small wildlife, including birds, is an especially attractive subject for the 800mm focal length.

When photographers covering events are not permitted close access to their subjects, including concerts, speaking events, etc., this focal length will provide the reach needed (primarily outdoors due to the F5.6 max aperture opening).

The 800mm focal length used on smaller APS-C/1.6x (FOVCF) imaging sensor format cameras provides an extremely narrow angle of view, equivalent to a 1280mm lens on a full-frame camera. This considerably narrower angle of view diminishes the scenarios this lens is ideally suited for, but it will excite some bird photographers.

Finding a subject in the narrow-angle of view provided by the 800mm focal length can be challenging, and the 1280mm equivalent angle of view will require greater skill to track a moving subject within. Moving back can be an answer, but obstacles can enter the sight path, and a longer distance permits heat waves to become a more significant issue.

While on the heat waves topic, just because you have a quality 800mm lens doesn't mean you can create sharp images with it, even when using the fastest shutter speeds and the best techniques. When present, heat shimmer/haze/waves create optical distortion that will diminish the quality of mid- and long-distance photos, a problem I frequently encounter at half this focal length.

The sun and moon are great subjects for the 800mm focal length. On that note, I'll borrow a focal length comparison example from the Meade Glass White Light Solar Filter Review (note that an 800mm lens pointed at the sun without a proper filter will destroy itself and the camera in seconds).

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Perhaps someday I can get the specific 400mm and 800mm focal lengths, along with the 2400mm option included here. Still, the 420mm and 840mm options are close to the point.

Max Aperture

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The Canon RF 800mm F5.6 L IS USM Lens has the longest focal length available in a lens with an f/5.6 max aperture (unless the 600mm f/4 plus 1.4x combination is considered). The resulting size and weight of the latest optical design at 800mm and f/5.6 is relatively small and light but still about as much as most photographers want to use.

While f/5.6 is a relatively narrow max aperture, aperture is measured as a ratio of lens opening to focal length. At 800mm, an f/5.6 aperture is huge, and this big opening is the primary reason for the large size, heavy weight (relative to lenses in general), and high cost of this lens. That aperture is also the key to this lens's usefulness.

When you want to stop motion, including sports action and moving wildlife, especially in the low light wildlife is most often active in and that sports are typically played in, f/5.6 will often be found barely adequate at best for the 800mm focal length magnification.

When you want to isolate the subject from even a busy, distracting background, this lens is among the best available. At f/5.6, the 800mm focal length creates a shallow depth of field that combines with the strong 800mm super-telephoto magnification to deliver one of the strongest background blurs available in any lens (at equivalent focus distances or subject framing, equal to 400mm f/2.8). Most of the common uses for this lens do not permit manipulation of the background, and the backgrounds found in many of the venues this lens will be used in tend to be busy and distracting. Use this lens to blur the distractions away, turning advertisement banners, fans, and their clothing, apparatus, gear, seating, brush, etc., into blurs of color, making the subject stand out, popping from the frame. This example illustrates the maximum blur this lens can create:

That result shows only color blur.

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. Image stabilization is an extremely valuable feature in any lens and especially in a telephoto lens. Capturing sharp imagery from a large 800mm lens may require image stabilization even when mounted on a solid tripod.

Practically everything in the EF 400mm f/2.8L IS III lens was new, including the image stabilization system that achieved an impressive up to 5-stop CIPA rating. The RF 400mm F2.8 L IS Lens upped that rating slightly to 5.5 stops, with the increase directly attributed to the RF mount (note that this lens does not support coordinated IS, but IBIS is said to still provide some benefits). Based on this RF lens, the RF 800mm F5.6 gets a rating that is a bit lower — 4.5 stops.

Rudy Winston, Canon USA, shares:

"Canon engineers claim no Coordinated IS with the RF800mm F5.6 L IS and 1200mm F8 L IS lenses. In-body IS has always had limits in effectiveness with progressively longer telephoto lenses – requiring more and more sensor movement to counter camera/lens shake, which obviously is effectively magnified by the longer focal lengths.

Our claim is 4.5 stops of *optical* IS with the RF800mm, and 4.0 stops of optical IS with the 1200mm. There's no word as to whether the IBIS system in cameras like the R3, R5 and R6 is totally shut down, or its effectiveness is minimized... keep in mind, however, that we claim the SAME stabilization correction with non-IBIS-equipped cameras like the EOS R, based on CIPA-compliant testing."

While the RF 800mm lens is light for its specifications, it is still not a light lens to handhold, and the narrow angle of view increases the handholding challenge. Still, IS should make handheld shooting possible with this lens.

Three stabilization modes are provided. Mode 1 (general-purpose), Mode 2 (for panning with a subject, one axis of stabilization is provided), and Mode 3. Mode 3 is useful for tracking erratic action. In this mode, image stabilization is active and ready for use the moment the shutter releases, but actual stabilization is not in effect until that precise time. As a result, the view seen through the viewfinder is not stabilized, allowing an erratically moving subject to be tracked without fighting against image stabilization trying to stabilize the view. Mode 3 is designed to detect panning motion, and when detected, the lens will only apply stabilization at right angles to the direction of the detected movement (like Mode 2).

The latest word from Canon is that mode 1 can optimally be used for nearly all situations, including while using a tripod or monopod and while photographing action. I find mode 3 IS optimal for tripod-mounted photography, yielding a stable view for composition yet compensating for vibrations, especially those caused by wind, during the exposure.

Expect a click to be quite audible when IS starts and again when it stops but only quiet whirring and clicking while IS is active. This IS implementation is exceptionally well behaved – the image in the viewfinder does not bounce when the system activates, and the image does not drift while IS is active. IS aids greatly in establishing ideal handheld subject framing.

Canon's super-telephoto lenses have a secondary IS mode that automatically senses a tripod in use, then attempting to eliminate shutter shock, wind vibration, and other sources of remaining movement.

While stopping camera motion-induced image blur is image stabilization's primary job, it has another significant benefit, aiding in AF precision. The camera's AF system can produce better focus precision if the image it sees is stabilized. Canon contends that this is true even with a subject in motion, and the 800mm f/5.6 combination producing a potentially shallow depth of field makes AF precision especially critical.

The weight of this lens enables it to be handheld for significant periods, and the image stabilization system in this lens greatly extends its versatility in that regard.

Note: when this lens is dismounted while the camera is powered on, the IS unit may make a rattle sound when the lens is moved.

Image Quality

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I usually start the image quality section of a super-telephoto lens review with superlatives. However, as discussed in-depth at the beginning of the review, this lens will not perform at the same level as the RF 400 L and RF 600 L.

Wide-open at f/5.6, the Canon RF 800mm F5.6 L IS USM Lens produces slightly soft images. Fortunately, the corner sharpness performance is similar to the center of the frame performance, avoiding further degradation.

Selecting a one or two-stop narrower aperture often provides at least minor sharpness improvement. In this case, f/8 brings a modest improvement. At f/11, diffraction begins playing a softening role, offsetting any further gains from the stopping down strategy.

The resolution chart is brutal/merciless on image quality, so let's take the testing outdoors, next looking at some 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) using the Standard Picture Style with sharpness set to 1 on a 0-10 scale.

Because comparison grade outdoor images require direct sunlight and direct sunlight results in heatwaves causing distortion, only wide-open f/5.6 results are shared below. The number for each link references the ISO setting used.

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While the field results from this lens do not rise to the quality level of the big RF 400mm and RF 600mm lenses, they are still decent.

When used on a camera that utilizes a lens's entire image circle, a lens can be expected to create peripheral shading at the widest aperture settings. At f/5.6, this lens has about 1.5 stops of corner shading, a relatively low amount for a wide-open aperture setting. The shading decreases to about 0.5 stops at f/8 and about 0.3 stops at f/11.

APS-C format cameras using lenses projecting a full-frame-sized image circle avoid most vignetting problems. In this case, the about half a stop of corner shading showing at f/5.6 will seldom be visible.

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 shown in our vignetting test tool to determine how your images will be affected.

Lateral (or transverse) CA (Chromatic Aberration) refers to the unequal magnification of all colors in the spectrum. 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 be seen in the site's image quality tool. Here is the extreme corner crop:

Only black and white colors should appear in that image, and that is what we see.

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 example below looks 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.

Modest color separation is visible here.

Bright light reflecting off 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, dependent 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.

On this lens, Canon utilizes Super Spectra Coating (SSC) and Air Sphere Coating (ASC) to combat flare. However, the high 26/18-element count increases the challenge in this regard.

Pointing an 800mm lens at the sun is a good way to destroy the lens and camera, and thus, the site's standard flare test results are not available for this lens. However, flare resistance to bright lights seems reasonable for the focal length and optical design.

This lens is void of noticeable geometric distortion.

As seen earlier in the review, it is easy to illustrate the strongest blur a lens can create, and telephoto lenses, especially this one, are inherently 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 two 100% crops from f/11 (for diaphragm blade interaction) images.

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The first example shows defocused highlights being smoothly filled, having typical concentric rings, and good round shapes (though the diaphragm blades do not close far to create f/11. The foliage example looks nice.

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 we're looking at here.

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

Overall, the Canon RF 800mm F5.6 L IS USM Lens produces excellent but not extraordinarily sharp image quality.

Focusing

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Critical for the success of a lens creating a shallow depth of field and used primarily to photograph subjects in motion is its AF performance. Canon's super-telephoto lenses have long delivered the best-available autofocus performance, and this lens continues that tradition.

However, extenders have an impact on AF speed, and the RF 800 has an integrated 2x extender. Additionally, we should expect the relatively narrow maximum f/8 aperture to further impact AF performance. Still, the RF 800 AF system performs well, focusing fast until low light conditions are encountered.

Based on the RF 400, the RF 800's AF system incorporates that lens's AF advantages. "Mechanically-related AF improvements include reduced drive load, thanks to glass materials in the focus lens group that are nearly one-fifth the previous weight." [Canon] Also included is the latest microprocessor for improved calculation speed.

In addition to being reasonably fast and accurate, this lens's internal AF system is quiet. Some quiet internal shuffling along with quiet clicks are heard by an ear next to the lens, but the sounds will probably not be noticeable when shooting.

This super-telephoto lens includes a Focus Preset feature. Set the Focus Preset to a specific distance. When your shooting needs require that particular distance, turn the white spring-loaded playback ring located in front of the focus ring, and the lens will automatically adjust to the preset distance. New with the EF 600mm III lens was a direction-sensitive feature that permits a different distance to be set for each rotation direction. The Focus Preset switch settings include OFF, ON, and ON with audible focus confirmation. Use this feature to quickly adjust focus to a known distance or to an approximate distance where fine-tuning can quickly attain proper focus.

A 3-position focus limiter switch allows focusing distances to be limited to a subset of this lens's focus distance range. In addition to the full range, restricted limits of 8.5-65.6' (2.6-20m) and 65.6' (20.0m) - ∞ are selectable for improved focus lock times and reduced focus hunting when photographing subjects remaining within these ranges.

Four autofocus stop buttons in the black ring near the objective lens allow autofocus to be temporarily stopped. I use Servo (continuous) focusing mode for shooting sports but sometimes shoot focus-and-recompose images such as portraits during the event. The autofocus stop feature makes it easy to obtain focus lock, turn off autofocus, and recompose with framing that places the active focus point(s) off of the subject, including in the periphery of the frame. Another excellent use for this feature is when an image has been captured with suboptimal framing. Simply press a focus stop button and then capture enough images to be stitched together during post-processing. Of course, switching the lens to manual focus mode has the same effect.

New on the 2010-announced super-telephoto lenses was a third focusing mode. In addition to AF and MF, a "PF" or Power Focusing mode was included, and this mode has returned with the RF and series III lenses. When first introducing this feature, Canon USA said the feature helped "...moviemakers achieve smoother and more appealing focus shifts when filming."

Turn the focus preset playback ring (very) slightly to get low-speed electronically-driven AF, and turn it to a greater degree to obtain a higher rate with the direction of ring rotation determining the direction of focus distance change. The feature works nicely, but you will need a solid tripod setup and a steady hand not to induce movement while turning the ring. The power focusing is extremely quiet. Note that AF does not work in PF mode, though manual focusing is available in this mode.

Those interested in manually focusing this lens have not been forgotten, and this lens's focus ring lens will provide a superb manual focus experience. Instead of a conventional mechanically-linked manual focus drive, Canon implemented electronic manual focusing starting with the EF 600mm III lens. This decision simplified the overall design, saving weight and increasing expected reliability — and seemingly preparing for the R-series technology.

The RF 800mm F8 L IS lens's manual focus ring is ideally located, is large, has a sharply-ribbed rubber surface with a great feel and ideal rotational resistance, and will be smooth with no play. With an ear against the lens, a series of tightly-spaced click sounds will be heard while manually focusing.

A feature commonly implemented on electronic focusing lenses is variable speed drive rate dependent on the focus ring rotational speed. Unfortunately, this feature is often not optimally implemented, and fortunately, Canon has a better option for this lens. Via a switch, this lens offers three linear drive speeds. Mode 1 adjusts the focus relatively quickly, and precise focusing is challenging in this mode. Mode 2 and 3 become respectively slower, enabling fine control over the focus distance. You don't want to use mode 3 setting to chase sports action, but this mode allows for precise manual focusing.

FTM (Full Time Manual) focusing is supported in AF mode while in One Shot Drive Mode, but the shutter release must be half-pressed for the focus ring to be enabled. I often manually adjust the focus distance to track action while I'm not actively shooting, such as watching sports action at the other end of the field or to pre-focus on where I expect the action to occur next. Note that FTM does not work if electronic manual focusing is disabled in the camera's menu (if this option is present). The lens's switch must be in the "MF" position and the camera meter must be on and awake for conventional manual focusing to be available.

The RF 800 is well-suited for AF during video recording. The smooth focusing will make focus distance transitions easy on the viewer's eyes.

Canon super-telephoto lenses have historically provided only modest maximum magnification. Maintaining a similar minimum focus distance with twice the focal length gives the RF 800mm lens a significant among all lenses 0.34x maximum magnification.

Following is a comparison table showing the recent and current Canon super-telephoto line-up as of review time.

Model	Min Focus Distance "(mm)		Max Magnification
Canon RF 100-500mm F4.5-7.1 L IS USM Lens	35.4	(900)	0.33x
Canon RF 200-800mm F6.3-9 IS USM Lens	31.5	(800)	0.25x
Canon RF 400mm F2.8 L IS USM Lens	98.4	(2500)	0.17x
Canon RF 600mm F4 L IS USM Lens	165.4	(4200)	0.17x
Canon RF 600mm F11 IS STM Lens	177.2	(4500)	0.14x
Canon RF 800mm F5.6 L IS USM Lens	102.4	(2600)	0.34x
Canon EF 800mm f/5.6L IS USM Lens	236.2	(6000)	0.14x
Canon RF 800mm F11 IS STM Lens	236.2	(6000)	0.14x
Canon RF 1200mm F8 L IS USM Lens	169.3	(4300)	0.29x
Sony FE 600mm f/4 GM OSS Lens	177.6	(4510)	0.14x

A subject measuring approximately 8.1 x 5.4" (206 x 138mmm) will fill the frame at the minimum focus distance.

The damselfly above patiently waited for the lens distance to be adjusted to the minimum focus distance.

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Extenders / Teleconverters

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As mentioned at the beginning of this review, the Canon RF 800mm F5.6 L IS USM Lens is compatible with the Canon RF 1.4x Extender and the Canon RF 2x Extender.

With the 1.4x behind it, this lens becomes an 1120mm f/8 lens. With the 2x mounted, it becomes a long 1600mm f/11 lens.

Weather-sealing and image stabilization are included. In addition, the lens's native minimum focusing distance is retained with extenders in use, and that means the maximum magnification value is multiplied by the extender's multiplier, a significant improvement.

With the RF 1.4x behind the RF 800 L, image sharpness is decreased moderately. Though the effects of diffraction become more apparent at f/11, stopping down 1 stop to f/11 shows some sharpness improvement. The RF 1.4x adds a tiny amount of barrel distortion but does not affect lateral CA.

As always, the image sharpness hit with the 2x is stronger than with the 1.4x, and 1600mm f/11 results are quite soft. The results at f/16, despite the softening effects of diffraction becoming significant, are noticeable better. The 2x increases lateral CA and slightly increases barrel distortion.

Extenders, especially 2x extenders, reduce AF speed, but the RF 800 with-extender autofocus performance on the Canon EOS R-series cameras remains remarkably good, even with a strongly defocused starting focus distance. Typically, low light AF performance is decreased modestly with extenders reducing the maximum aperture, with focus hunting more frequent at these apertures.

Build Quality & Features

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Canon's big white super-telephoto lenses are among the most elite DSLR lenses available and represent the Canon L Series's best. Professionals expect these lenses to deliver the ultimate performance in the most adverse environments. Despite the significant weight loss, the overall durability of the RF and EF version III 400mm lenses was increased over the already-impressive version II model, and the RF 800 is based on these lenses.

Improvements in manufacturing processes get some of the credit for the light weight strength, and fascinating is the use of a new carbon-reinforced magnesium alloy. "The high level of fluidity in this material enables injection molding (thixomolding) for a thin walled formation. For example, with the first group lens barrel on the 400mm model, we were able to achieve a barrel thickness of 0.8mm via injection molding, for a base that is 20% thinner than previous models, maintaining sufficient strength and lightness. The carbon-reinforced magnesium alloy is also used for the tripod base plate and the exterior of the barrel." [Canon]

As lens size increases, the difficulty of maintaining precision increases, and attention to detail has been shown in this lens design.

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As discussed, the RF 800 F5.6 L IS Lens utilizes the RF 400mm F2.8 L IS Lens design for its front, with an extended mount section to the rear.

This lens's switches are mostly recessed, with just enough raised surface to be usable with gloves on. Note that the IS ON/OFF switch is raised in the center vs. both sides for tactile differentiation.

As already mentioned, the focus ring feels great, and the shape of this ring aids in the quality experience. The focus recall ring is easy to locate tactilely, and a diamond pattern black ring provides a grip for handling.

Notably missing on this RF lens (and its design-sharing predecessor) is a control ring.

The color of this lens deserves attention. Heat gain, especially uneven heat gain, can cause problems for a lens's optical performance, and big lenses have a lot of surface area to catch sunlight. Canon has chosen white paint to avoid as much heat gain as possible, and the new paint formulation on the III better shields the lens from heat than the previous paint did. "Infrared reflective pigments with high reflectance and titanium oxide lens barrel coating with silica provide excellent UV weather resistance and heat reduction." [Canon] But, that is just the beginning of the heat-avoidance efforts designed into the RF and version III lenses.

A newly-developed heat shield coating reduces uneven heating, and a two-layer barrel structure design also helps mitigate thermal transfer effects into the lens elements. In addition, reducing the weight of the lens naturally reduces its overall thermal capacity.

This lens features excellent weather resistance (the RF 400m F2.8 L IS Lens sealing is illustrated above). Many outdoor events are held regardless of the weather, and the photographers required to cover them are forced to deal with the weather. While I recommend a rain cover when wet weather is expected, the unexpected that can be a bigger problem. I've used Canon weather-sealed super-telephoto lenses in rather heavy rain with no ill effects. In addition to being sealed from moisture, dust is another hazard this lens keeps out.

The front and rear lens elements are fluorine-coated for easier cleaning and to prevent dust and drips from adhering in the first place.

You will immediately recognize the ultra-high-quality construction when you pick up this lens.

The RF 800 can easily be handheld for reasonable periods, but a 6.9 lb (3140g) lens is not light for use in this manner.

The size of this lens garners attention. You look like you belong in some venues, and you will stand out in others. You'll get over the latter. Regarding the former, I find a lens such as this one gains me entrance to locations in venues that I would otherwise have been restricted from.

Here is a table of comparable Canon telephoto lenses with the size and weight specifications included.

Model	Weight (lbs/)		Dimensions w/o Hood ("/)		Filter	Year
Canon RF 100-500mm F4.5-7.1 L IS USM Lens	3.0	(1365)	3.7 x 8.2	(93.8 x 207.6)	77	2020
Canon RF 200-800mm F6.3-9 IS USM Lens	4.5	(2050)	4 x 12.4	(102.3 x 314.1)	95	2023
Canon RF 400mm F2.8 L IS USM Lens	6.4	(2890)	6.4 x 14.4	(163.0 x 367.0)	DI 52	2021
Canon RF 600mm F4 L IS USM Lens	6.8	(3090)	6.6 x 18.6	(168.0 x 472.0)	DI 52	2021
Canon RF 600mm F11 IS STM Lens	2.1	(930)	3.7 x 10.6	(93.0 x 269.5)	82	2020
Canon RF 800mm F5.6 L IS USM Lens	6.9	(3140)	6.4 x 17.0	(163.0 x 432.0)	DI 52	2022
Canon EF 800mm f/5.6L IS USM Lens	9.9	(4470)	6.4 x 18.1	(163.0 x 461.0)	DI 52	2008
Canon RF 800mm F11 IS STM Lens	2.8	(1260)	4.0 x 14.2	(101.6 x 361.8)	95	2020
Canon RF 1200mm F8 L IS USM Lens	7.4	(3340)	6.6 x 21.1	(168.0 x 537.0)	DI 52	2022
Canon EF 1200mm f/5.6L USM Lens	36.4	(16500)	9.0 x 32.9	(228.0 x 836.0)	DI 48	1993
Sony FE 600mm f/4 GM OSS Lens	6.7	(3040)	6.4 x 17.7	(163.6 x 449.0)	DI 40.5	2019

For many more comparisons, review the complete Canon RF 800mm F5.6 L IS USM Lens Specifications using the site's lens specifications tool.

While the RF 800 is relatively light and handholdable, I will primarily use this lens on a support for both comfort and stability reasons. Still, lighter weight makes it easy to lift a monopod off the ground to follow fast action handheld. Use the monopod to rest the setup between breaks in the action.

Here is a visual comparison:

Positioned above from left to right are the following lenses:

Canon RF 400mm F2.8 L IS USM Lens
Canon RF 800mm F5.6 L IS USM Lens
Canon RF 600mm F4 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 800mm F5.6 L IS USM Lens to other lenses.

The RF 800 F5.6 L IS utilizes the same 52mm drop-in filters as its 600mm predecessor and most of Canon's super-telephoto lenses. This lens's slot includes a drop-in filter holder that accepts 52mm threaded filters. A slim Canon Protect 52mm threaded filter comes installed. Note that the filter is part of the optical design of Canon's big lenses, effectively the rear element in the optical path. It also helpful for catching dust before it drops deep inside the lens.

The Canon Drop-In Circular Polarizing Filter PL-C 52 (WIII) may sometimes be found helpful. This filter has had several revisions solely for color changes, keeping up with the lens color changes. Subtracting light from an already narrow aperture is not so often needed or appreciated, but some may find neutral density filters useful for this lens, primarily for video recording in bright light.

The tripod foot has two differently-sized threaded inserts — 1/4" and 3/8". A Wimberley P50 Lens Plate permits quick attachment to Arca-Swiss compatible monopod and tripod head clamps. Mounting with two screws is important to prevent the plate from twisting, but note that most lens plates will require a 3/8"-16 to 1/4"-20 Reducer Bushing in the larger threaded insert. These are inexpensive, and it seems Canon could easily have included one in the box. Much better would have been to machine the needed Arca-Swiss dovetail grooves into the foot, as some other lens manufacturers do.

Replacing the Canon tripod foot with a Wimberley or Really Right Stuff Tripod Foot is popular and my preference.

Lens plates and replacement feet better permit ideal balancing on a tripod or monopod, especially helpful due to the balance point of the lens with a gripped camera mounted is slightly back from the rear threaded insert.

This tripod collar is exceptionally smooth and provides light click-stops at 90°-degree rotations. While the click stops cause a slight bump during rotation (such as when panning with a subject as a monopod tilts), I prefer to have the click-stops assisting me with finding center, aiding significantly in maintaining a level camera.

This super-telephoto lens's light weight reduces the demands of its support, but the exceptionally long focal length increases the vibration dampening requirement. As I've mentioned, this lens can be handheld for a time, but you will appreciate having support under the lens for longer periods of use (and for stabilizing the view). Avoiding future shoulder issues may not seem important today, but I assure you that you will one day appreciate having taken good care of your body in your youth. Keep your elbows in and shoulders at rest.

In the field RF 800mm lens testing relied on the exceptional ProMediaGear TR424L Pro-Stix Carbon Fiber Tripod. I recommend minimally using a strong ball head (such as the Really Right Stuff BH-55) with this lens. Much better (safer, easier) is to use a lens of this size on a gimbal-style head such as the Wimberley WH-200-S Sidemount Head. RF 800mm lens outdoor use utilized the ProMediaGear Katana Gimbal Head.

Two tripod collar feet were included with the EF 400mm f/2.8 version II lens, with one being a small foot designed for monopods. I never used the small one, and apparently, many others left their small foot in the box. The smaller monopod base plate is reportedly again available for the RF lenses, but it is now an optional accessory.

As first seen on the 400 IS II, the RF 800 F8 has a Kensington-type wire security lock under the tripod collar lock knob cap.

Load Comparison Images

Sharing the same front design, the RF 800mm F5.6 and RF 400mm F2.8 unsurprisingly share the same lens hood model. This hood is relatively rigid, rather light (9 oz, 255g), and huge, offering the lens element excellent protection from bright light, impact, and the elements. While this hood is quite rugged, protect it as a replacement will cost as much as a nice lens.

The big lens hood is sometimes an issue from a space standpoint, including packing space and space on the sidelines or other events. For those circumstances, there is the optional Canon ET-155B Short Lens Hood. The price tag is substantial for this one also.

The E-180E lens cap features a padded, rigid interior that protects the front lens element and a wrap-around nylon cover.

The included padded lens strap can be attached to the tripod ring, an attachment point that permits the camera to be rotated without the neck strap twisting around one's neck.

The Canon LS600 Soft Lens Case, the same sling-style (single strap) shoulder case included with the RF 600 F4 L, is included in the box.

This nylon case looks great, is relatively compact and lightweight, well-padded, easy to use with smooth-functioning zippers and large pulls, and has a round molded-plastic bottom that keeps it upright on a flat surface. A thin zippered pocket and a pair of strap attachment points are provided on both sides of the case. The shoulder strap is padded and strong, and breathable padding is provided on the strap's case side, adding to the shoulder-carrying comfort. The convenient hand strap on top is also strong, with breathable padding ensuring that grip is not lost. Four hook-and-loop-adjustable pads are provided for interior use.

This case is nicely sized to hold its intended cargo.

Making the case large enough for a mounted camera to fit would have been a nice alternative. The additional cost would have been little (especially relative to the cost of the lens), and the utility of the case would have been greatly increased.

Transporting a large lens with a camera mounted increases the risk of damage, but there are many times when I'm transporting a lens such as this one in a lower-risk manner and prefer quick access to the mounted lens or want to avoid mounting a lens in unfavorable conditions. For example, transporting the lens from field to field during a soccer tournament can be low risk. Or, when photographing wildlife, getting the lens into action fast can mean the difference between getting the shot and getting nothing. For air travel or shipping, I always separate the lens and body.

The LS600 weighs 2.2 lbs (2kg). That is another significant weight savings.

I transported the Canon RF 800mm F5.6 L IS USM Lens with a Canon EOS R5 and BG-R10 mounted in a MindShift Gear FirstLight 40L. The fit is snug.

Price, Value, Compatibility

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If you need significant "reach", this may be your lens. Howver, a low-volume niche lens with extremely high production costs results in an extremely high price tag. Only a select few photographers will find the cost-value proposition balanced favorably for a purchase.

As an "RF" lens, the Canon RF 800mm F5.6 L IS USM Lens is compatible with all Canon EOS R-series cameras. Canon USA provides a 1-year limited warranty.

The reviewed Canon RF 800mm F5.6 L IS USM Lens was online-retail purchased. It went on to enjoy the glamorous rental life.

Alternatives

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The first alternative to the Canon RF 800mm F8 L IS USM Lens to explore is the Canon RF 400mm F2.8 L IS USM Lens, with the Canon RF 2x Extender creating an equivalent 800mm f/5.6 lens from this model. The 400mm lens provides 400mm f/2.8 and 560mm f/4 options, but it does not have an answer to the 800mm + extender 1120mm f/8 and 1600mm f/11 capabilities.

As discussed at the beginning of this review, it was expected that the RF 800mm image quality would be slightly better than the RF 400 + 2x image quality, with peripheral improvements showing most strongly. The image quality comparison verifies that center of the frame improvement is present, but only slightly so. The RF 800 has less lateral CA in the periphery, showing that improvement verified.

The Canon RF 800mm F5.6 L IS USM Lens vs. Canon RF 400mm F2.8 L IS USM Lens comparison without the 2x factored in shows the RF 400 modestly lighter and shorter. However, the 2x is needed to balance this comparison, and with that optic factored in, the RF 400 tips the scales toward itself slightly though it remains slightly shorter. Most other factors are equalized when the RF 2x is included in the comparison. The RF 400 + RF 2x is considerably less expensive than the RF 800, and it is the optimal choice for a high percentage of photographers considering these options.

The Canon RF 600mm F4 L IS USM Lens is one of my most-used lenses, and fitted with a 1.4x extender, it becomes an 840mm f/5.6 lens worthy of comparison to the RF 800.

The image quality comparison shows the 600 + 1.4x combination producing slightly sharper image quality. Here is the 1120mm vs. 1200mm comparison.

The Canon RF 800mm F5.6 L IS USM Lens vs. Canon RF 600mm F4 L IS USM Lens comparison without the 1.4x factored in shows the two lenses weighing the same, and the RF 600 measuring slightly longer and wider. Add the 1.4x to the RF 600, and the scale tips by about 7 oz (200 g) in the RF 800's favor. The RF 1.4x adds 0.8" (20.5mm) to the RF 600's mounted length.

The RF 800 has a higher maximum magnification — 0.34x vs. 0.24 (with the 1.4x) — and extends to 1600mm with the 2x vs. 1200mm. The RF 600 + RF 1.4x is considerably less expensive than the RF 800, and it is the optimal choice for a high percentage of photographers considering these options.

Over in the EF lens lineup is the equally specified Canon EF 800mm f/5.6L IS USM Lens. Canon's MTF chart standard has changed since the EF lens's chart was created, so we don't have an apples-to-apples MTF comparison available.

With the site's image quality comparison created with different resolution cameras, creating a conclusion remains challenging. Likely, little improvement will be seen in an upgrade to the RF lens.

The EF 800mm lens is from a 14-year-older design that features more large, forward-positioned lens elements along with a large protective element, and the Canon RF 800mm F5.6 L IS USM Lens vs. Canon EF 800mm f/5.6L IS USM Lens comparison shows the EF 800 much heavier and slightly longer. The RF lens gets an extra aperture blade (9 vs. 8), has extra 0.5-stops of image stabilization rating advantage, and has a much shorter minimum focus distance that generates a considerably higher maximum magnification (0.34x vs. 0.14x). The RF 800 is considerably more expensive than the EF 800.

The RF 800mm F5.6 L Lens was simultaneously introduced with the Canon RF 1200mm F8 L IS USM Lens. Adding the Canon RF 1.4x Extender to the RF 800mm lens yields an 1120mm F8 lens. While not identical, the 1120mm and 1200mm focal lengths are close enough for the difference to matter little in comparison. The 800mm lens offers 800mm f/5.6, and the RF 1200 goes longer with the 2x mounted, 2400mm vs. 1600mm.

As illustrated in the MTF comparison at the beginning of this review, the RF 1200mm image quality should be slightly better than the RF 800mm + 1.4x image quality.

The Canon RF 800mm F5.6 L IS USM Lens vs. Canon RF 1200mm F8 L IS USM Lens comparison without the 1.4x factored in shows the RF 800 modestly lighter and smaller. However, the 7.9 oz (225g) 1.4x is needed to balance this comparison, and with that optic factored in, the RF 800 becomes slightly heavier but still modestly shorter. With a shorter minimum focus distance, the RF 800 has a higher maximum magnification (0.34x vs. 0.29x), and the 1.4x extends that difference (0.48x vs. 0.29x). The RF 800 + RF 1.4x is less expensive than the RF 1200, though both options are high-priced.

Use the site's tools to create additional comparisons.

Summary

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As shared, the Canon RF 800mm F5.6 L IS USM Lens is a niche lens, optimal for those requiring high-frequency use of 800mm or longer focal lengths. If the niche targeted by this lens is important to you, there is no better option for it.

Due to the extreme cost of the RF 800mm lens, an opportunity for unique imagery is readily available to those affording it. Still, I find it difficult to justify this lens over the Canon RF 400mm F2.8 and 600mm F4 L IS USM Lenses with extenders aside from when the 800mm plus a 2x extender combination is required.