Skip to content

Canon Patent: 24-70mm f/4, 28-200mm f/2.8-5.6, 20-60mm f/2.8-4 And 50mm f/1.4 (composite opticals)

Canon Patent

A new Canon patent application for RF-mount lenses with composite optical elements.

Canon patent 2024039231 (Japan, published 3/22/2024) discusses optical formulas and methods for four lenses with composite optical elements:

  • 24-70mm f/4
  • 28-200mm f/2.8-5.6
  • 20-60mm f/2.8-4
  • 50mm f/1.4

Guess the most interesting of the bunch is the 50mm f/1.4 lens. From the patent literature:

  • An object of the present invention is to provide a composite optical element that is small and lightweight and has high optical performance.
  • BACKGROUND ART: In recent years, there has been an increasing demand for shorter overall length and lighter weight of photographic optical systems. In order to reduce the overall length and weight of the photographic optical system, there is a method of increasing the refractive power of each lens and introducing an aspherical lens to correct various aberrations that occur as a result.
  • As an aspherical lens for a photographic optical system, there is a composite element formed by molding a resin layer onto a glass lens.
  • Composite elements have a high degree of freedom in selecting the glass material for the glass lens, and are easy to mold, so they are characterized by being easy to introduce into photographic optical systems.
  • Patent Document 1 discloses an optical system in which chromatic aberration is corrected by using a material with a low partial dispersion ratio for the glass of a composite lens and combining it with a resin having a high partial dispersion ratio. If resin is used as an aspherical lens, chromatic spherical aberration and chromatic curvature of field will increase, which is undesirable.
  • Accordingly, an object of the present invention is to provide a composite optical element that is small and lightweight and has high optical performance.

Example 1

  • Focal length: 24-67.90
  • F value: 4.12
  • Half angle of view: 41.33-17.67
  • Image height: 19.39-21.64
  • Total length: 108.50-142.13
  • Back focus: 20.95-50.49

Example 2

  • Focal length: 15.30-45.00
  • F value: 4.12
  • Half angle of view: 41.68-16.51
  • Image height: 11.60-13.65
  • Total length: 83.50
  • Back focus: 17.67

Example 3

  • Focal length: 50.03
  • F value: 1.44
  • Half angle of view: 23.39
  • Image height: 21.64
  • Total length: 113.51
  • Back focus: 13.51

Example 4

  • Focal length: 28.40-197.00
  • F value: 2.90-5.70
  • Half angle of view: 37.30-6.27
  • Image height: 18.97-21.64
  • Total length: 151.14-220.00
  • Back focus: 13.50-47.04

Example 5

  • Focal length: 21.00-60.00
  • F value: 2.90-4.10
  • Half angle of view: 45.79-19.29
  • Image height: 18.37-21.62
  • Total length: 135.70-126.50
  • Back focus: 22.43

Example 6

  • Focal length: 390.03-275.02
  • F value: 2.91-3.08
  • Half angle of view: 3.21-4.52
  • Image height: 21.84-21.72
  • Total length: 347.00
  • Back focus: 46.20

More Canon patents are listed here.

[via asobinet]

Back To Top


This website or its third-party tools use cookies, which are necessary to its functioning and required to achieve the purposes illustrated in the cookie policy. If you want to know more or withdraw your consent to all or some of the cookies, please refer to the cookie policy.
By closing this banner you agree to the use of cookies.