Canon RF 20mm f/1.4L VCM Review

Introduction

Ease of Use

Weighing in at 636g / 1.40lb and measuring 99.3mm / 3.91 inches in length, the RF 20mm F1.4L VCM is a pleasingly compact and lightweight fast ultra-wide-angle prime lens that you can carry around all day without noticing.

It's very well-matched to a larger sized camera body like the Canon EOS R6 Mark III body that we tested it with, as shown in the product photos.

This lens is also very well built, fully living up to the professional designation that Canon have given it, as denoted by the "L" moniker in the product name.

It has an L-series level weather-resistant design to help protect it against dust and moisture and an advanced front element flourine coating to repel oil and moisture for easy maintenance.

Also found around the front of this lens is the distinctive red ring which is found on all Canon L series “professional lenses”. While this doesn't actually do anything, it's there to indicate that the lens adheres to the highest possible standards that Canon offers.

In terms of features, the RF 20mm F1.4L VCM provides most of the features that you'd expect to find on a modern hybrid lens.

There’s a traditional AF/MF switch for moving between manual focus and autofocus.

The round unmarked Lens Function button provides quick access to a specific camera feature, such as zebra or false colour functions in video mode.

Three different rings are found around the lens.

Located at the base of the lens barrel is the Iris ring, which provides smooth, click-free adjustments of the aperture in 1/32 steps running from f/ 1.4 to f/16 while filming video, or shooting stills. There's also an A (Auto) setting if you want the camera to take control.

The accompanying Iris lock switch unlocks and/or locks the iris ring for manual iris control when recording video.

The largest ring, found in the centre of the lens barrel, is the manual focusing ring. It has a good amount of give, making it not too loose and not too tight - it’s just the right amount to make precise manual focusing easy.

Manual focusing is done in a traditional fashion, with the adequately sized focus ring electronically coupled to the moving lens elements, although there are no hard stops at either end. Focusing is fully internal and the 67mm filter thread does not rotate on focus.

With the RF 20mm lens attached to a Canon R6 Mark III body, auto-focusing proved to be very quick and almost silent in most situations thanks to the Voice Coil Motor (VCM).

This combination proved to be capable of locking focus on a subject almost instantly, even when alternating between close and faraway subjects. 

The last ring found at the end of the lens barrel is the smallest of the three and again has a different textured coating.

This control ring can be used for a number of different functions that can be customised from within the main camera menu. You can use it to adjust the aperture (with a click), shutter speed, ISO or exposure compensation. Alternatively you can switch it off so it does nothing.

In practice, using this lens with most Canon camera bodies effectively provides three different ways of setting the aperture for both video and stills - clickless via the Iris ring, with a click via the control ring, and using the control dial on the camera body.

This is perhaps one too many ways to perform the same function - I would have preferred a single aperture/iris ring that could be de-clicked via a physical switch - but presumably Canon have additionally implemented a more video-friendly clickless iris ring because the control ring that's found on the vast majority of their RF lenses always has a click.

This lens does not feature built-in image stabilisation, instead relying on the camera body to provide it. The in-body image stabilization found in certain Canon EOS R-series cameras (such as the EOS R1) provides an even more impressive 8 stops of compensation in the centre and 5 stops in the corner.

As there's no built-in image stabilisation, this lens does not have a physical button that allows you to switch the image stabiliser on or off, so you'll need to change this via the camera body's menu system.

This lens has a rear filter holder that enables cut gel filters to be used at the same time as a front-mounted 67mm filter.

Included in the box is a lens hood (EW-73H), which is easy to attach to the lens - simply line up the red dot with the red marking on the lens and twist into place. You can also reverse the lens hood for reducing the overall size when transporting the lens. There's also a good quality lens pouch (LP1219).

Focal Range

The Canon RF 20mm F1.4L VCM's focal length of 28mm provides an angle of view of 94°.

Chromatic Aberrations

Chromatic aberrations, typically seen as blue or purple fringes along contrasty edges, were not especially apparent in our test shots, only appearing in very high contrast areas.

Vignetting

When shooting JPEGs, with the lens set to its maximum aperture of f/1.4, there is some obvious light fall-off in the corners, requiring you to stop down by at least 2 f-stops to prevent it.

There's a much larger amount of vignetting evident in the RAW files, though, but thankfully the camera body automatically and successfully applies corrections to the JPEG files, resulting in an acceptable out-of-camera image.

JPEG

RAW

Distortion

You can't actually turn off distortion correction in an EOS R camera body when this lens is used - the menu option is actually greyed out and unavailable - which perhaps gives you a good idea of just how much correction the camera is applying!

Still, distortion is well controlled in the resulting JPEG images, so arguably the combination of camera and lens are doing a good job. Again make sure to apply the correct lens profile in post-production for RAW files.

JPEG

RAW

Sunstars and Flare

The Canon RF 20mm F1.4L VCM is capable of creating some nice sunstars when stopped-down to f/16, as shown below, and flare is also well controlled even when shooting directly into the sun.

Macro

The Canon RF 20mm F1.4L VCM offers a very useful minimum focusing distance of just 20cm / 7.87", with a maximum magnification of 0.19x.

Bokeh

Bokeh is a word used for the out-of-focus areas of a photograph, and is usually described in qualitative terms, such as smooth / creamy / harsh etc.

In the RF 20mm F1.4L VCM lens, Canon have employed an iris diaphragm with 11 rounded blades, which has resulted in very nice bokeh in our view for such a wide-angle lens.

We do realise, however, that bokeh evaluation is subjective, so we've included lots of examples below for your perusal.

Sharpness

In order to show you how sharp the Canon RF 20mm F1.4L VCM lens is, we are providing 100% crops on the following page.