Marketed	October 2023
Original Price	Open price
Lens Construction (group)	12
Lens Construction (element)	16
No. of Diaphragm Blades	9
Minimum Aperture	22
Closest Focusing Distance (m)	0.25
Maximum Magnification (x)	0.12
Filter Diameter (mm)	None (inserted in gelatin filter holder at the rear of the lens)
Maximum Diameter x Length (mm)	Approx. 83.7×112
Weight (g)	Approx.570

The RF10-20 mm F4 L IS STM realizes ultra-wide angle shooting and high image quality throughout the entire zoom range. Ultra-wide angle shooting with a focal length of 10 mm enables dynamic expression with an impressive sense of perspective, such as shots covering a wide range of surroundings indoors and in other limited spaces, or shots of vast landscapes and celestial bodies.By covering a focal length of up to 20 mm, it offers a high degree of freedom in expression that leverages the zoom function in both still images and video shooting. In addition, chromatic aberration is corrected over the entire zoom range by effectively arranging 16 lenses in 12 groups, including 1 Super UD^*1 lens and 3 UD^*1 lenses. This allows for high-quality images with minimal color bleeding, making the lens suitable for shooting in a variety of situations.

This product features 5.0-stop^*2 in-lens optical image stabilization. When combined with an EOS R series camera, which is equipped with an in-body image stabilization mechanism, the combination results in camera-lens coordinated correction. For example, when attached to the EOS R3 (released in November 2021), this lens achieves 6.0 stops^*3 of image stabilization. The lens newly supports camera-lens coordinated correction for peripheral area image blur typical of wide-angle shooting, thus enabling comfortable shooting even in situations where camera shake frequently occurs, such as night photography.

This lens is significantly smaller and lighter than preceding products due to the large aperture and short back focus^*4 features of the RF mount, as well as a design that integrally works with the camera's distortion aberration correction function. Compared to the EF11-24 mm F4L USM (released in February 2015), the weight has been reduced from approximately 1,180 g to approximately 570 g, and the total length has been reduced from approximately 132 mm to approximately 112 mm, giving the lens excellent mobility. Despite its compact and lightweight design, the lens’ mount, control ring and focus ring have been made dust- and drip-resistant^*5, granting superb reliability that only an L lens can provide.

*1 Lens made of UD (ultra-low dispersion) glass. A Super UD lens has substantially greater performance than a UD lens and produces the result of two UD lenses, which is almost equivalent to a fluorite lens.
*2 When attached to EOS R (released in September 2018), at a focal length of 20 mm. Based on CIPA standards (Yaw/pitch directions)
*3 At a focal length of 20 mm. Based on CIPA standards (Yaw/pitch directions)
*4 Meaning that the distance between the image capture surface of the sensor and the nearest lens surface is short.
*5 Complete dust and water droplet prevention is not guaranteed.