Canon RF 600mm f/11 IS STM lens
The Canon RF 600mm f/11 IS STM lens has a light weight, effective stabilisation, and an affordable price, making it a ‘no-brainer’ for keen photographers of birds and other types of wildlife.
That same combination will make this lens attractive to sports photographers, enabling close-ups that were formerly impossible to obtain without professional equipment.
There are a couple of downsides to consider when evaluating this lens, and plenty more upsides – see the full review.
Announced on 9 July 2020 concurrently with a similar lens with an 800mm focal length, Canon’s RF 600mm f/11 IS STM lens and its longer sibling represent a revolutionary new development in the super-telephoto category. At only 930 grams, it is less than a third of the weight of the EF 600mm f/4L IS III USM lens. But that’s not all; its listed price of AU$1449 is roughly a twelfth of the AU$18,399 price of the EF 600mm f/4L IS III USM lens, its DSLR equivalent. At last there is a super telephoto lens for all of us!
Angled view of the new RF 600mm f/11 IS STM lens with inner barrel retracted. (Source: Canon.)
A considerable amount of lateral thinking has been put into the development of the new 600mm and 800mm lenses – and it started with the aim of breaking ‘through the three barriers of “heavy, big, and expensive” for super-telephoto lenses’, to quote Chief Product Planner, Kengo Iezuka, who was interviewed by Japanese magazine DC Watch. It also meant looking back to the late 1950s when Canon began exploring the possibilities of simple super-telephoto lenses based upon the design of a refractor telescope.
Jump forward 60 years and that design can be adapted for the 21st century through the use of diffractive optics (DO), which were pioneered by Canon in the EF 400mm f/4 DO IS USM lens, which was launched in 2001. The plastic DO element reduces the overall weight of the lens without compromising image quality.
The optical design of the RF 600mm f/11 IS STM lens showing the position of the DO element. (Source: DC Watch.)
Accordingly, the RF 600mm f/11 IS STM lens uses one DO lens in its construction, which consists of 10 elements in seven groups (shown above). It’s a third-generation DO lens with gapless dual-layered diffractive optical elements made from a new material that enables the diffraction lattices to be held together with no air between them. This allows light to pass through with minimal loss of intensity and suppresses ring-shaped flare.
The RF 600mm f/11 IS STM lens in use with inner barrel extended. (Source: Canon.)
To keep the lens transportable, Canon has used a double-barrel structure with a ‘collapsible mechanism’ that requires the outer barrel to be pushed forwards, extending the overall length of the lens by 70 mm. A locking ring near the end of the outer barrel must be turned to the left to release the clamp holding it in place and then turned back to the right to secure it when the barrel is in the extended position.
Any camera the lens is fitted to will recognise when the lens is not in the correct shooting position and post a warning on its monitor and EVF screens. Note: older EPS R and RP cameras will require a firmware update before they can use this lens.
Autofocusing is driven by a stepping motor which is controlled from the camera. This enables the lens to support the fast, high-precision AF algorithms in the latest cameras as well as using the same AF sensors. It also allows the lens to be used with the new RF 1.4x and 2x extenders.
However, the in-body camera shake correction provided in the EOS R5 and EOS R6 is relatively ineffective since the degree of correction possible with a telephoto lens is small compared to a wide-angle lens. Instead, the RF 600mm f/11 IS STM lens has its own built-in shake correction that is CIPA rated for up to five stops.
Like other RF lenses, the RF 600mm lens supports in-camera corrections for distortion, peripheral illumination and chromatic aberration of magnification. Users can also take advantage of the Digital Lens Optimizer (DLO).
The RF 600mm f/11 IS STM lens is supplied with front and end caps but its hood (ET-88B) is an optional extra. While we generally recommend the use of lens hoods, if you’re looking for one for this lens be prepared for frustration; we couldn’t find one local re-seller who had it listed with or without the lens.
We tested the review lens on the EOS RP camera for which it is a ‘natural’ partner. Its light weight and compact size are well balanced on this camera’s body, although any of the current EOS R cameras would work well with this lens.
Who’s it For?
Birders are the most obvious target market for the RF 600mm f/11 IS STM lens and its 800mm sibling. The combination of affordable price, light weight and effective stabilisation make this a ‘no-brainer’ for keen photographers of birds – and also other types of wildlife.
That same combination will make this lens attractive to sports photographers as well as plane and train spotters (the former in particular since these lenses will enable close-ups that were formerly impossible to obtain without professional equipment). The superior mobility the 600mm lens allows makes it possible to cover sports action using a hand-held camera. This will allow a wider range of viewpoints by providing the photographer will more flexibility when choosing where to shoot from.
There are a couple of downsides to consider when evaluating this lens. Some are common to all super-telephoto lenses, regardless of their maximum aperture, while others specific to the fixed-aperture lenses are addressed in the next section of this review.
On the positive side, since focusing is fully internal, you can fit and use angle-critical filters like polarisers and graduated filters without having to constantly re-adjust them. And the 82 mm filters are readily available and affordably priced.
Overall, this lens is a lot of fun to use and can provide both valuable learning experiences and some great photos. Depending on what kinds of subjects you use it for, a lens like this can provide you with close-ups that were previously unobtainable without cropping the frame and some interesting perspective compressions. The bokeh of the lens is attractive enough to produce aesthetically satisfying results as well.
Like all super-telephoto lenses, the small field of view (3.4 degrees horizontal, 4.1 degrees diagonal in the case of the 600mm lens) can make it difficult to find your target. This is true for ANY lens with a 600mm focal length and should be taken into account.
Autofocusing with this lens can be tricky at times, due in part to the relatively small f/11 maximum aperture of the lens. We found it could take a second or two for the EOS RP camera and 600mm lens to find focus with subjects close to its minimum focusing distance (4.5 metres).
The lens won’t focus any closer, even in manual focus mode, and hunting is common when focusing upon subjects that are 5-6 metres from the camera. Fortunately, manual override is readily available so you can take control when it’s needed.
Choosing the best shooting mode for the camera is also tricky because there’s no point in using Av mode, since the aperture is not adjustable. We found it best to set the camera to P mode or Tv mode, using the latter to allow the use of relatively slow shutter speeds for testing purposes.
If you want to keep the ISO as low as possible, make sure you set appropriate limits in the Auto ISO parameters in the camera. Make a few tests to find out the slowest shutter speeds you can use with minimal risk of camera shake and lock that into the menu setting. We found it possible to use the lens hand-held at shutter speeds down to 1/25 second with good shooting technique.
The ISO range you set will depend on the ambient light levels of your subjects. In bright conditions, most photographers should be able to keep ISO settings relatively low. However, when photographing birds in forests or sporting events in indoor stadiums, you will probably be forced to use settings of ISO 1600 or higher. While this should create few issues with Canon’s EOS R cameras, we’d caution against using settings higher than ISO 6400 if you plan to make A3 or larger prints.
Build and Ergonomics
Most of the components in this lens are made from moulded resin, which is light and strong as well as relatively easy to manufacture. Metal components have been ‘kept to the minimum necessary parts’, according to Megumi Inazumi, a key member of the design team.
Readers interested in how this lens is put together can find out by reading the Lens Rentals ‘teardown’ of the lens, which was published in August 2020. We highly recommend this article, which is both informative and entertaining.
The most important factor to understand with this lens is its unconventional construction, which harks back to old-fashioned refractor telescopes and appears to be very solid for a mostly plastic lens assembly. While the lens is fitted to the camera in a conventional fashion, if you turn the camera on at that point it will display the following message: Set the lens to the shooting position. You can’t take photos while the lens is retracted.
We’ve copied this diagram from the instructions supplied with the RF 600mm f/11 IS STM lens to illustrate the positions of the various controls and features.
The lock ring must be rotated to the left so you can push the outer barrel forwards and then to the right to lock the barrel into the shooting position. The lens is now ready for use. To prepare the lens for transport or storage, the same steps must be followed in reverse. Note: The lock ring can only be set in position when the barrel is fully extended or retracted.
At the front of the outer barrel is a bayonet fitting for attaching the optional ET-88B lens hood. Inside this fitting is the 82 mm diameter filter thread. The front section of the lens is 50 mm long and has four moulded areas plus a leatherette cladding to provide a secure grip. The upper and lower mouldings are wider than those on the sides.
Behind the front section is the control ring, which is made from metal and is hatched to provide a secure grip while making it easy to identify. As on other RF lenses, this ring can be set to adjust a frequently-used function like shutter speed or ISO speed. It has a click action to indicate adjustment steps, which are controlled by the camera.
The focusing ring is just behind the control ring. It’s 35 mm wide and covered with rubberised ribbing. Focus is driven by the camera, using sensors that cover 40% of the frame horizontally and 60% vertically.
Behind the focusing ring is a 37 mm wide section of the barrel containing the brand and focal length names plus slider switches for the focus limiter/distance selector, AF/MF mode selector and image stabiliser on/off switch. When the camera’s AF mode is set to [ONE SHOT] full-time manual focus override is available when the shutter button is half-pressed.
A tripod mount panel with a metal-lined socket is located on the bottom side of this section of the lens. It is compatible with standard 1/4-20 UNC screws. No collar is provided, partly because this lens is designed mainly for hand-held use.
The lock ring is located just behind this section. It is 32 mm wide and slopes inwards for approximately 10 mm close to the camera. Its leading section carries a series of thick mouldings that provide a secure grip. A Lock/Unlock indicator is stamped on the left side of this ring.
The camera end of the lock ring indicates the edge of the inner barrel, which fits entirely within the outer barrel when the lens is retracted. A 20 mm wide band separates the outer barrel from the chromed metal lens mount. No rubber flange is present to prevent ingress of moisture or dust, confirming this lens is not weather-resistant.
We’ve already mentioned the fact that the RF 600mm f/11 IS STM lens is supplied without a lens hood, which is the first accessory we would recommend for anyone who takes photographs out-of-doors in brightly-lit conditions. While the lens delivered images with adequate contrast without a hood – and most modern image editors and raw file converters provide facilities for boosting sharpness and contrast – a hood would reduce potential glare and make it a bit easier to focus precisely when fine-tuning focus manually.
Canon also provided us with the RF 2x extender to use with both the 600mm and 800mm lenses. Weighing only 340 grams and adding just under 40 mm to the overall length of the lens to which it is attached, it consists of nine elements in five groups.
A close-up view of the RF 2x extender in use, showing the index marks for fitting it and the locking clip that holds it in place.
Fitting this extender reduces the effective aperture by two f-stops to f/22 without affecting the minimum focusing distance so you can obtain even better close-ups if that’s your objective. Image quality should not be compromised but the 2x magnification gives you a 1200mm focal length, which will make it more challenging to find your targets when shooting hand-held.
Canon’s instructions state you must attach the extender to the lens before fitting the lens to the camera body. Index marks on both extender and lens make this process straightforward. A locking clip at the lens end of the extender keeps it in place and makes it easy to detach the extender when it has to be removed.
Unlike the f/11 lenses, the RF 2x extender boasts a dust and drip-proof design, which makes it a good match for the new RF 100-500mm f/4.5-7.1L IS lens. It can also take advantage of the built-in stabilisation in any lens it is used with. Because of its robust construction, the RF 2x extender is not cheap; expect to pay around AU$1200 for it.
We have been unable to carry out our normal Imatest tests on this lens because of a lack of space in our testing setup so our performance evaluations have been made on the basis of subjective assessments. All our tests were carried out with EOS RP camera bodies and all shots were captured as RAW+JPEG pairs.
We’ve provided a number of enlarged crops to demonstrate how sharply the test lens could focus upon and resolve subjects. We’ve also included examples of using the lens for sports, wildlife and landscape photography as well as images taken with the RF 2x extender.
All samples have come from CR3.RAW files, which were converted into 8-bit JPEGs with Adobe Camera Raw, our preferred raw file converter. This was done to get around any in-camera processing that might have occurred by default with JPEG files straight from the camera.
While we carried out the usual evaluation of vignetting, shots could only be taken at f/11 so it’s not surprising to find some vignetting present in the images. There was little point in assessing rectilinear distortion, since it’s unlikely to occur in super-tele lenses. Both issues are largely irrelevant with the main subject types for which this lens is best suited.
The review lens also appeared to be free from chromatic aberration, as shown in the image provided in the Samples section, which was taken from an unprocessed CR3.RAW file. A cropped section at 100% magnification is provided to confirm this assessment.
We’ve also provided a couple of examples showing how precisely the lens can focus under different lighting conditions and with different subjects. Again, crops at 100% magnification demonstrate its performance. Samples are also provided to show the lens in use with the RF 2x extender.
We found bokeh to be variable and, not unexpectedly, dependent on the nature of the background. With evenly-lit backgrounds it could be smooth and attractive but bright highlights in out-of-focus backgrounds were usually outlined and sometimes showed an ‘onion-ring’ effect.
One factor worth noting – and one that is shared with all super-telephoto lenses – is the effect of the atmosphere on image quality, especially when you’re shooting in hazy conditions. The greater the distance between the camera and the subject, the more haze will intrude between them and reduce contrast and colour saturation in the scene.
To some degree, both can be recovered with post-capture processing through use of contrast and saturation adjustments, along with the Haze Reduction tool provided in Adobe Camera Raw. However, the resulting images aren’t always as sharp and colour rich as they would have been if shot from closer distances with a shorter, faster lens.
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Picture angle: 3.4 degrees horizontal, 4.1 degrees diagonal
Minimum aperture: f/11 (fixed aperture)
Lens construction: 10 elements in 7 groups (including gapless dual-layered diffractive optics elements)
Lens mounts: Canon RF
Diaphragm Blades: None
Weather resistance: No
Focus drive: Stepping motor plus lead screw
Stabilisation: Yes, 5.0 stops
Minimum focus: 4.5 metres
Maximum magnification: 0.14x
Filter size: 82 mm
Dimensions (Diameter x L): 93 x 199.5 mm retracted (269.5 mm (extended)
Weight: 930 grams
Standard Accessories: E-8211 lens cap, end cap
RRP: AU$1449; US$699
Distributor: Canon Australia; 1800 021 167
ISO 200, 1/250 second at f/11.
A crop from the above image at 100% magnification showing no coloured fringing.
ISO 200, 1/100 second at f/11.
A crop from the above image at 100% magnification.
ISO 100, 1/50 second at f/11.
A crop from the above image at 100% magnification.
Shot from the minimum focusing distance of 4.5 metres; ISO 1600, 1/250 second at f/11. Note the attractive bokeh with evenly-lit backgrounds.
The same subject photographed from roughly the same distance with the RF 2x extender fitted; ISO 1600, 1/80 second at f/22. (An additional butterfly arrived while we were fitting the extender.)
ISO 100, 1/200 second at f/11.
ISO 100, 1/200 second at f/11.
ISO 1600, 1/500 second at f/11.
ISO 1600, 1/250 second at f/11.
ISO 1600, 1/40 second at f/11.
ISO 1600, 1/60 second at f/11.
The same subject photographed from roughly the same distance with the RF 2x extender fitted; ISO 1600, 1/40 second at f/22.
ISO 1600, 1/10 second at f/11.
ISO 800, 1/800 second at f/11.
ISO 400, 1/320 second at f/11.
This image demonstrates the effect of haze on shots of distant landscapes; ISO 320, 1/640 second at f/11.
It’s possible to recover some contrast and saturation with a capable raw file converter; although the results are seldom natural-looking.
Slight haziness can be effectively corrected with subjects at medium distances; ISO 1000, 1/500 second at f/11.
Highlight outlining in the out-of-focus background; ISO 200, 1/200 second at f/11.
The same subject photographed at the minimum focusing distance; ISO 200, 1/200 second at f/11.
An example of perspective compression with the 600mm lens; ISO 640, 1/640 second at f/11.
Another examples of perspective compression, which is especially evident in the fence on the left of the frame; ISO 1600, 1/640 second at f/11.
RRP: AU$1449; US$699
- Build: 9.0
- Handling: 9.0
- Image quality: 9.0
- Autofocusing: 8.9
- Versatility: 8.5