Canon Patent Application: Canon RF 13-20mm F2.8

Seems Canon is busy dreaming up drool worthy lens designs for us to salivate over.

Here's another one that may be a very interesting lens.  Perhaps a 15-35mm F2.0 is too much, and Canon has to relax it a bit to a mere 16-35mm F2.4?

Personally I  don't think this will ever come to manufacturing since it's too close to the 15-35mm F2.8L that already exists.

Another example of this patent application is a really curious lens that will probably not get created because again, it's too close to an already existing Canon RF 15-35mm.  It's a Canon RF 13-21, or what will probably would be a 13-20mm F2.8.

Canon's objective in this patent application is to create a lens with chromatic aberrations and what is loosely translated as secondary spectrum (I assume this may be longitudinal chromatic aberration) is sufficiently corrected.

As the back focus is certainly shorter than the EF mount, this is most certainly an RF design. Curiously it's not what looks like a traditional RF design with a larger rear element.

From the patent itself;

an object of the present invention, at negative lead type zoom lens configuration, by properly setting the arrangement of the first lens group, while achieving wider angle and large aperture, primary zoom range It is an object of the present invention to provide a zoom lens having high optical performance in which the chromatic aberration of magnification and the secondary spectrum are satisfactorily corrected, and an imaging apparatus using the same.

Canon RF 16-35mm F2.4 Details

focal distance    16.49  23.34  33.95  
F Number           2.47   2.47   2.47  
picture angle     52.69  42.83  32.51  
image height      21.64  21.64  21.64  
full length      167.86 162.91 163.52  
BF                27.91  37.29  51.28

Canon RF 13-21mm F2.8 Details

focal distance    13.40  17.30  21.20  
F-Number           2.88   2.88   2.88  
angle of view     58.23  51.35  45.58  
image height      21.64  21.64  21.64  
full length      150.15 136.89 130.04  
BF                20.96  25.13  29.31  

Canon Patent Application 2020-030251