New Canon 50mm f/1.4 – an EF-mount Defocus Smoothing lens?

One of the most intriguing optics on the Canon RF lens roadmap (opens in new tab) is the Canon RF 85mm f/1.2L USM DS – the DS standing for 'Defocus Smoothing'. Now it looks like Canon is working on a DS lens for its EF-mount system, thanks to a patent for a new EF 50mm f/1.4 optic. 

So what is a Defocus Smoothing lens? A spiritual successor to Canon's earlier Softfocus lens (opens in new tab), Canon's Product Intelligence Consultant, David Parry, explained (opens in new tab) it thusly: "Using different lens elements, it will give a different look to foreground and background blur and a much smoother look to the bokeh effect. And that will change with aperture as well, so you'll be able to get different degrees of effect on that depending on what aperture you're using."

In a recent interview with DP Review (opens in new tab), Canon's Japanese engineers revealed that this defocusing is achieved using an apodization effect. This is accomplished via the introduction of an additional optical element that creates a smooth, Gaussian-like dispersion of the gradation towards the edges of lens elements – which in turn reduces the harshness at the edges of characteristics such as 'bokeh balls'. 

And, as unearthed by Canon News (opens in new tab), Japanese patent JP,2019-056780,A (opens in new tab) describes a new 52.43mm f/1.49 lens for the EF mount with just such an apodization element.  

The addition of a concave apodization element produces the defocus smoothing effect in the Canon patent

The addition of a concave apodization element produces the defocus smoothing effect in the Canon patent

"Generally, in the medium telephoto imaging lens system from the wide-angle, sagittal halo of off-axis light beam causes uneven intensity of defocus image at the image peripheral portion. For this reason, it is possible to improve the appearance of an out-of-focus image in an off-axis light flux by providing the light flux with a transmittance distribution by the apodization filter and effectively removing the sagittal halo."

Part of the apodization process is that it reduces light transmission, delivering an effectively lower t-stop than the f-stop would indicate, as the patent continues: "At that time, effective removal of the sagittal halo while suppressing the decrease in light quantity is required as the performance of the apodization filter." 

So, Canon has patented a new EF-mount lens with the same apodization effect as that seen in its upcoming RF 85mm DS (which could well be one of the best Canon lenses (opens in new tab)). Is it fair to conclude that this is the start of a new Defocus Smoothing line of Canon lenses? 

The company certainly patents far more tech than ever sees the light of day, but a continued commitment to its EF mount optics – not to mention an inclination towards more artistic lenses – would be very welcome indeed. 

Read more:

5 Canon RF lenses make European debut at The Photography Show (opens in new tab)
The best Canon camera lenses in 2019 (opens in new tab)
Canon patents new superzoom lenses for EF and RF mounts (opens in new tab)

Thank you for reading 5 articles this month* Join now for unlimited access

Enjoy your first month for just £1 / $1 / €1

*Read 5 free articles per month without a subscription

Join now for unlimited access

Try first month for just £1 / $1 / €1

James Artaius

The editor of Digital Camera World, James has 21 years experience as a magazine and web journalist and started working in the photographic industry in 2014 (as an assistant to Damian McGillicuddy, who succeeded David Bailey as Principal Photographer for Olympus). In this time he shot for clients as diverse as Aston Martin Racing, Elinchrom and L'Oréal, in addition to shooting campaigns and product testing for Olympus, and providing training for professionals. This has led him to being a go-to expert for camera and lens reviews, photographic and lighting tutorials, as well as industry analysis, news and rumors for publications such as Digital Camera Magazine (opens in new tab)PhotoPlus: The Canon Magazine (opens in new tab)N-Photo: The Nikon Magazine (opens in new tab)Digital Photographer (opens in new tab) and Professional Imagemaker, as well as hosting workshops and demonstrations at The Photography Show (opens in new tab). An Olympus and Canon shooter, he has a wealth of knowledge on cameras of all makes – and a fondness for vintage lenses and instant cameras.