Canon Patent Application: Canon EF Supertelephotos

With the complexity and cost of modern super-telephoto lenses, most likely more than one patent gets applied to the newest generation of super telephotos.  Canon hasn't stopped research and development on EF super telephotos.  It could mean that we'll see one more generation of them.

If you notice, with these telephoto designs, the core of the elements is near the back.  There's only one element now at the front of the lens. These lenses would have a dramatic weight re-balance over older designs.

This patent application is looking at making the super telephoto quick focusing and reducing aberrations.

As an optical system used in an image pickup apparatus such as a digital camera or a video camera, a large-aperture telephoto optical system having a long focal length and a small F number has been demanded. In addition, there is a demand for an optical system having high optical performance which can easily perform quick focusing and satisfactorily corrects various aberrations, particularly chromatic aberration which greatly affects optical performance. Conventionally, an optical system satisfying such a demand has been known.

Canon EF 300mm F2.8L IS USM

focal length 294.00  
F number 2.91  
Half angle of view (degree) 4.21  
Image height 21.64  
lens length 276.40  
BF 65.35 

Canon EF 400mm F2.8L IS USM

Focal Length 392.00  
F number 2.90  
Half angle of view (degrees) 3.16  
Image height 21.64  
Total lens length 371.25  
BF 69.92  

Canon EF 500mm F4.0 IS USM

Focal Length 490.00  
F-number 4.12  
Half angle of view (degrees) 2.53  
Image height 21.64  
Lens length 410.77  
BF 66.03  

Canon EF 600mm F4.0L IS USM

Focal length 588.00  
F-number 4.12  
half angle (in degrees) 2.11  
Image height 21.64  
total lens length 474.78  
BF 80.59  

Canon EF 800mm F5.6L IS USM

focal length 784.00  
F-number 5.80  
half angle (in degrees) 1.58  
Image height 21.64  
total lens length 484.53  
BF 75.94

Japan Patent Application 2020-013166

• JPO