RF50mm F1.2 L USM

RF50mm F1.2 L USM

Beautiful bokeh and sharpness that transcend conventional standard lenses powerfully expand the world of expression for any user. What makes this high imaging capability possible is the large, maximum f/1.2 aperture in this standard single focal-length lens. The large-diameter, short back focus characteristics of its RF mount enable flexible optical design and an unprecedented evolution of the lens. An effective arrangement of ground aspherical elements and UD elements suppress chromatic aberration to bring outstanding image performance to photographs as a whole. A special coating technology, ASC, further reduces the flaring and ghosting that can degrade an image. A lens that pursues the highest levels in breadth of expressiveness and in every facet of operability and robustness, the RF50mm F1.2 L USM breaks open new possibilities for lenses.


  • RF50mm F1.2 L USM, Canon EOS R, 1/100sec., f/1.2, ISO320
  • RF50mm F1.2 L USM, Canon EOS R, 1/125sec., f/8, ISO100
  • RF50mm F1.2 L USM, Canon EOS R, 1/125sec., f/11, ISO100
  • RF50mm F1.2 L USM, Canon EOS R, 1sec., f/2.5, ISO100


Angle of View
(horizontal, vertical, diagonal)
40°/ 27°/ 46°
No. of Diaphragm Blades 10
Closest Focusing Distance 0.4m
Maximum Magnification 0.19x
Water/dust Resistance Yes *
Filter Size 77mm
Max. Diameter x Length Ø89.8 × 108mm
Weight Approx. 950g
Lens Cap E-77 II
Lens Hood ES-83
Lens Pouch/Case LP1319

  • UD element
  • Ground aspherical lens
  • GMo aspherical lens
  • ASC
  • Fluorine Coating

MTF Characteristics

Spatial frequency Maximum aperture
10 lines/mm
30 lines/mm
How to read
MTF characteristics

Spatial frequency Maximum aperture
10 lines/mm
30 lines/mm

The more the S and M curves are in line, the more natural the blurred image becomes.

Modulation Transfer Function, or MTF, is a method of evaluating lens performance using contrast reproduction ratio. When evaluating the electrical characteristics of audio equipment, one important measure of performance is frequency response. This indicates the fidelity of the reproduced sound with respect to the source sound as it passes through the microphone, recording and playback circuits, and finally the speakers. When the reproduction is accurate, the equipment is classified as “hi-fi,” or “high fidelity.”
In the same way, when a lens is viewed as a transmission system for optical signals, measuring the frequency response of the optical system reveals whether the optical signal is transmitted faithfully. For a lens, the equivalent of frequency is “spatial frequency,” which indicates how many patterns, or cycles, of changes in sinusoidal density are present in a 1 mm width. Accordingly, the unit of spatial frequency is lines per mm, as opposed to Hz in electrical systems.

The MTF characteristics shown on this website are 10 lines/mm and 30 lines/mm, where the horizontal axis indicates image height (the distance on a diagonal line from the center of the image, in mm) with the image center set to 0, and the vertical axis indicates contrast. The closer the 10-line/mm curve is to 1, the better the contrast and clarity of the lens; the closer the 30-line/mm curve is to 1, the better the resolving power and sharpness of the lens. Although a good balance between both of these is important for a lens to be sharp and clear, a lens is generally said to offer excellent image quality if the 10-line/mm curve is greater than 0.8, or satisfactory image quality if greater than 0.6.

Resolving power and contrast are both good

Contrast is good; resolving power is poor

Resolving power is good; contrast is poor

  • *This lens needs to have Canon filters attached to achieve its dust-resistance and water-resistance performance.