Canon RF 50mm f/1.2 L USM lens
Although the RF 50mm f/1.2L USM lens represents a substantial investment in weight and cost, it also delivers at the highest levels of performance.
The RF 50mm f/1.2L USM combines a standard focal length, similar to the ‘natural’ field of view of human vision, with a fast f/1.2 maximum aperture that enables shooting in low light levels and provides the benefits of selective focusing techniques. Like the RF 24-105mm f/4 L IS USM lens, it features Canon’s customisable Control Ring and is designed to take advantage of the short back focus Canon’s EOS R cameras.
Angled view of the RF 50mm f/1.2L USM lens. (Source: Canon.)
The optical design of this lens is complex for a prime lens, comprising 15 elements in nine groups. That’s considerably more than the equivalent EF lens, which has eight elements in six groups and is much smaller and lighter. Exotic elements include three aspherical lenses – two ground aspherics and one glass-moulded – and one UD (Ultra-low dispersion) lens.
The optical diagram for the RF 50mm f/1.2L USM lens showing the positions of the exotic elements. (Source: Canon.)
Air-Sphere Coating (ASC) has been applied to one surface to enhance the anti-reflective properties of the lens and minimise ghosting and flare. The iris diaphragm has 10 rounded blades that create a circular aperture for attractive bokeh. The minimum aperture is f/16 and the lens will focus down to 40 cm.
Unlike the RF 24–105mm f/4 L IS USM lens, this lens is not stabilised. However, it boasts the same levels of dust- and water-resistant sealing as Canon’s L-series lenses, enabling it to be used in inclement conditions.
The positions of the dust- and drip-resistant seals in the RF 50mm f/1.2L USM lens. (Source: Canon.)
Autofocusing is driven by a ring-type ultrasonic motor that works with optimised algorithms and a high-speed CPU to ensure fast, precise and quiet autofocus performance when shooting stills and video clips. Full-time manual focus override is available by simply moving the focusing ring, while users can switch to manual focusing at any time via a slider on the lens barrel.
Focusing is internal, enabling hassle-free use of angle-critical filters and keeping potential contaminants out while the lens is being focused. The lens suffers slightly from focus breathing, which causes a small degree of magnification at close focus distances. This will be more significant to videographers than stills shooters.
Who’s it for?
‘Nifty Fifty’ lenses have been popular since the birth of 35mm photography and the new fast-50s have enjoyed a resurgence in recent years. Unfortunately, the asking price for this lens will deter many potential purchasers. Costing approximately 185% more than the current price of the EF 50mm f/1.2L USM lens and roughly 165% heavier, the RF 50mm f/1.2L USM lens represents a substantial investment.
Although photographers who require the highest levels of performance for professional or scientific applications (such as astrophotography) will probably be prepared to pay the price in dollars and weight, it’s less versatile than the RF 24-105mm f/4 L IS USM zoom lens, which is also significantly cheaper. More significantly for those with legacy lenses, the EF 50mm f/1.2L USM lens and the EF to RF Control Ring adapter will be significantly cheaper as well as roughly 20 mm shorter and 230 grams lighter.
So-called ‘standard’ prime lenses have long been considered versatile enough to be used for a wide range of subject types, from event photography to landscapes, fashion, product, street and travel shooting. With a minimum focusing distance of 40 cm, this lens isn’t ideal for macro work, although it can be used for shooting close-ups of larger flowers and small animals.
Build and Ergonomics
Its wide f/1.2 maximum aperture makes this a relatively large and heavy lens, measuring 108 mm in length and weighing 950 grams (without the lens hood). But it is very solidly built and both the lens and its hood carry the ‘Made in Japan’ label.
Canon doesn’t list the materials used in the construction of this lens but our guess is that it has a substantial amount of metal in its barrel, which is protected with a tough, matte-black plastic coating. The mount is solid chromed steel with a bayonet fitting that connects to the camera.
The front element of this lens is roughly 40 mm in diameter and it is recessed into the lens barrel by approximately 20mm. The filter ring is located inside the top of the outer barrel, with the bayonet mounting for the lens hood on the outer side.
The Control Ring begins 10 mm behind the front of the lens. It’s identical to the ring on the RF 24–105mm f/4 L IS USM lens and has a textured surface and click stops to enable easy adjustments of the programmed function.
The focusing ring is situated 5 mm aft of the Control Ring. It’s 27 mm wide and entirely covered with a finely-ribbed rubber grip band. Being driven from the camera, it turns through 360 degrees when power is off and provides little tactile feedback when the camera is powered-up. Autofocusing is fast and accurate.
Behind the focusing ring, the remainder of the lens barrel extends for approximately 50 mm sloping inwards twice before reaching the metal lens mount. Sliders for the AF/MF selection and the focus limiter (Full/ 0.8 m to infinity) are located in this section close to the trailing edge of the focusing ring and accessible by the left hand. No other controls or scales are provided.
The lens is supplied with front and end caps plus a large petal-shaped lens hood made from solid black plastic with a bayonet fitting, internal ridging to prevent reflections and a locking button to keep it in place. A soft carrying pouch is also provided.
Our Imatest tests showed the review lens to be a top-class performer, delivering higher than expected resolution across a wide range of aperture settings. Measurements taken in JPEG files both near the centre of the frame and towards the edge comfortably exceeded expectations between f/2.8 and f/8, where diffraction began to take effect. (Raw files delivered even higher resolution.)
Apertures wider than f/2.8 were close to or slightly above expectations around the centre of the frame and just below expectations near the periphery, as shown in the graph of our text results below.
Because the EOS R automatically corrects chromatic aberration in JPEGs, we have used the data from CR3.RAW files to produce the graph of the results of our tests below. It shows lateral chromatic aberration well down in the ‘negligible’ band the upper edge of which is defined by the red line. We found little or no coloured fringing in our raw file test shots and in-camera corrections completely removed it from JPEGs.
Autofocusing was very quiet as well as fast and generally accurate, provided the correct AF point or area was selected. This is particularly important with the f/1.2 maximum aperture, where depth of field is paper-thin.
We found some evidence of focus ‘breathing’ at close focusing distances, where the image frame becomes slightly cropped as the closest focus point is approached. While not significant for stills shooters, it can become visible in video recordings when focus is ‘pulled’ between close and distant subjects.
Aberrations like vignetting and distortion are corrected automatically in JPEGs so we had to assess raw files to determine whether they were significant. We found both vignetting and distortion to be effectively negligible.
Bokeh was smooth and attractive, even with the lens stopped down as far as f/4. We found traces of highlight outlining in some shots at this point, particularly with backlit subjects. However, evenly-lit backgrounds were very smooth and the shallow focus ensured a nice blending of tones.
Despite the lack of stabilisation in either the EOS R body or the lens, we were able to use shutter speeds as low as 1/10 second when shooting hand-held and obtain reasonably sharp images with roughly 25% of shots. This is due mainly to the effective integration of the lens with the camera body, which makes for comfortable and steady shooting.
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Picture angle: 46 degrees
Minimum aperture: f/16
Lens construction: 15 elements in 9 groups (including 3 aspherical and 1 UD elements plus Air Sphere and fluorine coatings)
Lens mounts: Canon RF
Diaphragm Blades: 10 (circular aperture)
Focus drive: Nano USM (ring-type)
Minimum focus: 40 cm
Maximum magnification: 0.19x
Filter size: 77 mm
Dimensions (Diameter x L): 89.8 x 108 mm
Weight: 950 grams
Standard Accessories: Lens front and end caps, ES-83N lens hood, LP1319 lens pouch
Distributor: Canon Australia; 1800 021 167; www.canon.com.au.
Based on JPEG files taken with the EOS R camera.
Vignetting at f/1.2.
Bokeh at f/1.2 with an evenly-lit background; ISO 100, 1/3200 second.
Bokeh at f/1.2 with an uneven background; ISO 100, 1/2000 second. Traces of highlight outlining are just visible.
Bokeh at f/2; ISO 100, 1/1000 second. Outlining can be seen along brighter highlights.
Backlit close-up at f/2; ISO 100, 1/8000 second. Note the choppy background bokeh.
Showing the shallow depth of field, even with the lens stopped down; ISO 200, 1/100 second at f/10.
ISO 100, 1/400 second at f/10.
Crop from the above image enlarged to 100% showing little or no coloured fringing;
Hand-held shot at ISO 100, 1/8 second at f/2.8.
ISO 100, 1/320 second at f/8.
ISO 100, 1/100 second at f/6.3.
ISO 100, 1/200 second at f/5.6.
ISO 100, 1/200 second at f/7.1.
ISO 100, 1/250 second at f/8.
ISO 200, 1/100 second at f/6.3.
ISO 200, 1/25 second at f/10.
ISO 200, 1/640 second at f/9.
ISO 200, 1/100 second at f/16.
ISO 200, 1/250 second at f/11.
ISO 200, 1/125 second at f/16.
Additional image samples can be found with our review of the EOS R camera.
RRP: AU$3599; US$2299
- Build: 9.0
- Handling: 9.0
- Image quality: 9.3
- Versatility: 8.9