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

Canon RF 800mm F5.6 L IS USM Lens

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.

ModelWeight (lbs/g)Dimensions w/o Hood ("/mm)Elements/Groups
Canon RF 400mm F2.8 L IS USM Lens6.37(2890)6.4 x 14.4(163.0 x 367.0)17/13
Canon RF 400mm F2.8 L IS USM Lens + 2x7.12(3230)6.4 x 15.9(163.0 x 406.2)26/18
Canon RF 800mm F5.6 L IS USM Lens6.93(3140)6.4 x 17.0(163.0 x 432.0)26/18
Canon RF 800mm F5.6 L IS USM Lens + 1.4x7.42(3365)6.4 x 17.8(163.0 x 452.3)33/22
Canon RF 600mm F4 L IS USM Lens6.81(3090)6.6 x 18.6(168.0 x 472.0)17/13
Canon RF 600mm F4 L IS USM Lens + 2x7.56(3430)6.6 x 20.1(168.0 x 511.2)26/18
Canon RF 1200mm F8 L IS USM Lens7.37(3340)6.6 x 21.1(168.0 x 537.0)26/18

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.

Canon RF 1200mm F8 L IS USM Lens Design Diagram Comparison

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.

Canon RF 1200mm F8 L IS USM Lens MTF Chart Comparison

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 will not provide sharpness (contrast and resolution) close to the RF 400 without extenders, but it will 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 tag on the RF 800 and RF 1200 lenses is 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 appear to have a slight image quality advantage in the comparisons at their native focal length, the primary advantage of these lense 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 noticeable diffraction impact even on lower resolution cameras.

Canon RF 1200mm F8 L IS USM Lens MTF Charts

These charts do not exude optimism in regards 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 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 capabilities of the latest cameras 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.

Canon RF 800mm F5.6 L IS USM Lens Top View

Focal Length

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.

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 a 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, avoid crossing a creek, stay back from the surf, stay out of view, etc.

When you want to capture a compressed look from a distant perspective, you might want a 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 F8 max aperture opening).

The 800mm focal length used on smaller APS-C/1.6x (FOVCF) imaging sensor format cameras (none are available with an RF mount as I write this) 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 heatwaves to become a more significant issue.

While on the heatwaves topic, just because you have a quality 800mm lens doesn't mean that 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 mi- 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).

Canon RF 800mm F5.6 L IS USM Lens Focal Length Example

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

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 nearly 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.

Canon RF 800mm F5.6 L IS USM Lens Angle View with Hood

Image Stabilization

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 1200mm 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 1200mm lens is very 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 am increasingly finding 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 noticeable click to be audible when IS starts and again when it stops but only very quiet whirring and clicking while IS is active. Also expect this IS implementation to be exceptionally well behaved – the image in the viewfinder should not jump around when the system activates, and the image should 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 very 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.

Image Quality

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.

Selecting a one or two stops narrower aperture often provides at least minor sharpness improvement. However, only one stops remains between the wide-open f/5.6 aperture and f/11, where diffraction begins playing a softening role, likely offsetting any further gains from that strategy.

The final image quality analysis awaits arrival of this lens.


Critical for the success of a lens creating a very 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 is expected to continue that trend.

However, extenders have an impact on AF speed, and the RF 1200 has an integrated 2x extender. Additional, we should expect the relatively narrow maximum f/8 aperture to further impact AF performance. Still, the RF 1200 AF system should perform well until very low light conditions are encountered.

Based on the RF 600, the RF 1200'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 very accurate, this lens's internal AF system should be very quiet. Some quiet internal shuffling along with quiet clicks will likely be 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 14.1-98.4' (4.3-30m) and 98.4' (30.0m) - ∞ 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 (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 1200mm 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 very 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 to watch 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 1200 is well-suited for AF during video recording. The smooth focusing will make focus distance transitions easy on the viewer's eyes, and the camera's mic will not pick up the sound of the lens focusing.

Canon super-telephoto lenses generally do not have the shortest minimum focusing distances among lenses in general. The latest Canon RF and EF 600mm F4 L IS Lenses improved upon previous versions in this regard. Maintaining a similar minimum focus distance with twice the focal length gives the RF 1200mm lens a significant among all lenses 0.29x maximum magnification.

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

Canon RF 100-500mm F4.5-7.1 L IS USM Lens35.4"(900mm)0.33x
Canon RF 400mm F2.8 L IS USM Lens98.4"(2500mm)0.17x
Canon EF 400mm f/2.8L IS III USM Lens98.4"(2500mm)0.17x
Canon EF 400mm f/2.8L IS II USM Lens106.3"(2700mm)0.17x
Canon EF 400mm f/4 DO IS II USM Lens129.9"(3300mm)0.13x
Canon RF 600mm F4 L IS USM Lens165.4"(4200mm)0.17x
Canon EF 600mm f/4L IS III USM Lens165.4"(4200mm)0.15x
Canon EF 600mm f/4.0L IS II USM Lens177.2"(4500mm)0.15x
Canon RF 600mm F11 IS STM Lens177.2"(4500mm)0.14x
Canon RF 800mm F5.6 L IS USM Lens102.4"(2600mm)0.34x
Canon EF 800mm f/5.6L IS USM Lens236.2"(6000mm)0.14x
Canon RF 800mm F11 IS STM Lens236.2"(6000mm)0.14x
Canon RF 1200mm F8 L IS USM Lens169.3"(4300mm)0.29x
Sony FE 600mm f/4 GM OSS Lens177.6"(4510mm)0.14x

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

Canon RF 800mm F5.6 L IS USM Lens Maximum Magnification Example

Extenders / Teleconverters

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 a 1120mm f/8 lens. With the 2x mounted, it becomes a very 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. With the effects of diffraction becoming more apparent, stopping down 1 stop to f/11 will likely show little or no improvement in sharpness. Expect the 1.4x III to add a slight amount of barrel distortion but 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 will be rather soft. The results at f/16, with the softening effects of diffraction becoming significant, will not be good. The 2x will likely increase lateral CA and slightly increase barrel distortion.

The with-extender autofocus performance on the Canon EOS R-series cameras should be remarkably good. Typically, low light AF performance is decreased modestly with extenders reducing the maximum aperture, with focus hunting not unlikely at these apertures.

Canon RF 800mm F5.6 L IS USM Lens Side View

Build Quality & Features

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 8000 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 to maintain precision increases, and attention to detail has been shown in this lens design.

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 extending 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 new 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.

Canon EF 400mm f/2.8L IS III USM Lens Weather Sealing

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 for preventing dust and drips from adhering in the first place.

Canon EF 1200mm f/8L IS III USM Lens Fluorine Coating

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 this use.

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 at this one gaining 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.

ModelWeight (lbs/g)Dimensions w/o Hood ("/mm)FilterYear 
Canon RF 400mm F2.8 L IS USM Lens6.4(2890)6.4 x 14.4(163.0 x 367.0)DI 522021
Canon EF 400mm f/2.8L IS III USM Lens6.3(2840)6.4 x 13.5(163.0 x 343.0)DI 522018
Canon EF 400mm f/2.8L IS II USM Lens8.5(3850)6.4 x 13.5(163.0 x 343.0)DI 522011
Canon EF 400mm f/4 DO IS II USM Lens4.6(2100)5.0 x 9.2(128.0 x 232.7)DI 522014
Canon RF 600mm F4 L IS USM Lens6.8(3090)6.6 x 18.6(168.0 x 472.0)DI 522021
Canon EF 600mm f/4L IS III USM Lens6.7(3050)6.6 x 17.6(168.0 x 448.0)DI 522018
Canon EF 600mm f/4L IS II USM Lens8.7(3920)6.6 x 17.6(168.0 x 448.0)DI 522011
Canon RF 600mm F11 IS STM Lens2.1(930)3.7 x 10.6(93.0 x 269.5)822020
Canon RF 800mm F5.6 L IS USM Lens6.9(3140)6.4 x 17.0(163.0 x 432.0)DI 522022
Canon EF 800mm f/5.6L IS USM Lens9.9(4470)6.4 x 18.1(163.0 x 461.0)DI 522008
Canon RF 800mm F11 IS STM Lens2.8(1260)4.0 x 14.2(101.6 x 361.8)952020
Canon RF 1200mm F8 L IS USM Lens7.4(3340)6.6 x 21.1(168.0 x 537.0)DI 522022
Canon EF 1200mm f/5.6L USM Lens36.4(16500)9.0 x 32.9(228.0 x 836.0)DI 481993
Sony FE 600mm f/4 GM OSS Lens6.7(3040)6.4 x 17.7(163.6 x 449.0)DI 40.52019

For many more comparisons, review the complete Canon RF 1200mm F8 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 the monopod off the ground to follow fast action handheld. Use the monopod to rest the setup between breaks in the action.

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 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.

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.

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.

The light weight of this super-telephoto lens 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.

For tripod mounting, I recommend using a strong ball head (such as the Really Right Stuff BH-55 or Arca-Swiss Z1) 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, Wimberley Tripod Head II, or Really Right Stuff PG-02.

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 as well. 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.

Canon RF 800mm F5.6 L IS USM Lens Hood Comparison

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.

Canon ET-155B Short Lens Hood for EF 400mm f/2.8L IS III USM 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.

Canon EF 400mm f/2.8L IS III USM Lens Cap

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

Canon EF 600mm f/4L IS III USM Lens Strap

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.

Canon EF 600mm f/4L IS III USM Lens Case LS600

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.

Canon EF 600mm f/4L IS III USM Lens Case Pads

This case is nicely sized to hold its intended cargo.

Canon EF 600mm f/4L IS III USM Lens Case Open

Making the case large enough for a mounted camera to fit would have been a nice alternative. The additional cost would have been very 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 old 600B hard case weighs 9.6 lbs (4.35kg) empty, while the new LS600 weighs 2.2 lbs (2kg). That is another significant weight savings.

Price, Value, Wrap Up

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 is expected to be online-retail sourced.

Alternatives to the Canon RF 800mm F5.6 L IS USM Lens

The first alternative to the Canon RF 800mm F8 L IS USM Lens I'd like 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, the RF 800mm image quality should be slightly better than the RF 400 + 2x image quality, with peripheral improvements showing most strongly.

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.

Over in the EF lens line-up 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 comparison available. I expect to see improved peripheral image quality from 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 very high-priced.

Use the site's tools to create additional comparisons.

Canon RF 800mm F5.6 L IS USM Lens Angle View


As shared, the Canon RF 800mm F5.6 L IS USM Lens is a niche lens, optimal for those requiring the 800mm focal length more than occasionally or needing a focal length longer than 800mm. 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.

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