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)

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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]

Canon RF 24-70mm f/2.8L vs EF 24-70mm f/2.8L II – Is There A Difference?

Canon RF 24-70mm F/2.8L
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Many Canon EOS R owner wonder if they should replace their EF lenses with RF versions, or just use the EF lenses with the adapter. Here is a RF 24-70mm f/2.8L vs EF 24-70mm f/2.8L II comparison.

Todd Dominey wanted to know if there is any difference between the Canon RF 24-70 f/2.8L and the Canon EF 24-70mm f/2.8L II. He says:

Is there a qualitative difference between the RF 24-70 and the decade-old EF 24-70 II? I was curious to find out, so I photographed the world’s largest junkyard of vintage cars (~4500 rusting vehicles across six miles) using both lenses on the Canon EOS R5.

More RF 24-70mm f/2.8L IS review stuff is listed here.

Canon RF 24-70mm f/2.8L IS:

America: B&H Photo, Adorama, Amazon USA, Amazon Canada, Canon Canada, Canon USA
Europe & UK: Amazon DE, Amazon UK, Amazon IT, Canon IT, WEX Photographic, Canon FR, Canon UK, Canon DE

Canon EF 24-70mm f/2.8L II:

America: B&H Photo, Adorama, Amazon USA, Amazon Canada, Canon Canada, Canon USA
Europe & UK: Amazon DE, Amazon UK, Amazon IT, Canon IT, WEX Photographic, Canon FR, Canon UK, Canon DE

Canon Patent: RF 24-70mm f/4-7.3 IS Lens (compact and lightweight)

Canon Patent
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Here is a new Canon patent application. Once more for an RF mount lens, a compact and lightweight standard zoom lens with image stabilization.

Canon patent application 2021-196449 (Japan) discusses optical formulas for a RF 24-70mm f/4-7.3 IS lens. Not the fastest lens but according to the patent literature a lens of small size and little weight.

PROBLEM TO BE SOLVED: To provide a compact zoom lens which satisfactorily corrects aberration fluctuation at the time of image shake correction and can obtain high optical performance at the time of image shake correction over the entire zoom range.

In recent years, in digital still cameras and video cameras, there is a demand for a zoom lens having a compact size and high resolution (high optical performance). Further, it is required that the zoom lens is provided with a mechanism (vibration-proof mechanism) for compensating for image shake (image shake) that occurs when accidental vibration such as camera shake is transmitted. As a zoom lens that meets these demands, a negative lead type zoom lens in which a lens group having a negative refractive power is arranged on the most object side is known. In this negative lead type zoom lens, an anti-vibration mechanism that compensates for image shake by moving a part of the lens group (vibration-proof group, image shake correction group) so that it has a component in the direction perpendicular to the optical axis is provided.

Example 1

  • Focal length: 24.86-68.13
  • F value: 4.12-7.31
  • Half angle of view: 38.31-17.62
  • Image height: 19.64-21.64
  • Overall length: 102.91-104.95
  • Back focus: 13.00-37.46

Example 2

  • Focal length: 28.68-67.45
  • F value: 4.12-7.16
  • Half angle of view: 34.41-17.78
  • Image height: 19.64-21.64
  • Overall length: 105.26-115.51
  • Back focus: 13.00-36.88

The patent application was spotted by asobinet.com. More Canon patent applications are listed here. Some particularly interesting patent applications we think might get into production are these:

Canon Patent: 24-100mm f/2.8 And 24-70mm f/2-3.5

Canon Patent
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Here is a new Canon patent application, for a 24-100mm f/2.8 and a 24-70mm f/2-3.5 lens. The design seems to be agnostic, meaning no mount type is specified.

Canon patent application 2021-189218 (Japan) discusses optical formulas for two lenses: 24-100mm f/2.8 and a 24-70mm f/2-3.5.

Example 1

  • Zoom ratio 3.92
  • Wide-angle intermediate telephoto
  • Focal length 24.72 48.69 97.00
  • F number 2.90 2.90 2.90
  • Half angle of view 37.60 23.96 12.57
  • Lens total length 119.56 132.86 152.43
  • BF 5.30 10.90 19.16

Example 2

  • Zoom ratio 2.75
  • Wide-angle intermediate telephoto
  • Focal length 24.72 40.75 67.96
  • F number 2.06 3.50 3.50
  • Half angle of view 37.60 27.97 17.66
  • Lens total length 105.84 115.84 131.74
  • BF 13.77 21.03 28.47

Example 3

  • Zoom ratio 2.75
  • Wide-angle intermediate telephoto
  • Focal length 24.72 40.96 67.96
  • F number 2.90 2.90 2.90
  • Half angle of view 37.60 27.84 17.66
  • Lens total length 93.83 105.51 121.76
  • BF 3.29 10.64 20.42

Example 4

  • Zoom ratio 3.92
  • Wide-angle intermediate telephoto
  • Focal length 24.72 48.16 97.00
  • F number 2.90 3.50 3.50
  • Half angle of view 37.60 24.19 12.57
  • Image height 19.04 21.64 21.64
  • Lens total length 98.44 114.37 139.82
  • BF 3.88 12.29 24.26

More Canon patent applications are listed here. Some particularly interesting patent applications we think might get into production are these:

[via asobinet.com]

Deal: Tokina AT-X 24-70mm f/2.8 PRO FX Lens – $569 (reg. $899, today only)

Tokina AT-X 24-70mm
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Today only (03/01/21) B&H Photo DealZone has a 37% discount on the Tokina AT-X 24-70mm f/2.8 PRO FX for Canon EF mount.

At a glance:

  • EF-Mount Lens/Full-Frame Format
  • Aperture Range: f/2.8 to f/22
  • Three Glass Molded Aspherical Elements
  • Three SD Super-Low Dispersion Elements
  • Multi-Layer Lens Coatings
  • Silent-Drive Module AF System
  • Internal Focus; One-Touch Focus Clutch
  • Nine-Blade Diaphragm

Get the Tokina AT-X 24-70mm f/2.8 PRO FX on sale at $569. Compare at $899.

Hand-picked deals are listed here.

Deal pages:

Refurbished lenses and DSLRs at Canon Store (best deals to be found here)

Save $10 on Luminar 4 and/or Aurora HDR 2019 and/or Luminar AI using our code “WATCH” at checkout.

Click here to open the rest of the article

Hot: Sigma 24-70mm f/2.8 DG OS HSM IF ART – $879 (reg. $1299, expires tomorrow)

Sigma 24-70mm F/2.8
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Adorama has a great deal on a great lens: the Sigma 24-70mm f/2.8 DG OS HSM IF ART with a 32% discount.

Get the Sigma 24-70mm f/2.8 DG OS HSM IF ART on sale at $879. Compare at $1,299.

Sigma 24-70mm f/2.8 DG OS HSM IF ART at a glance:

  • Mount with dust- and splash-proof design
  • Fast AF with full-time manual focus
  • Compatible with Mount Converter MC-11
  • Available SIGMA USB DOCK
  • Available Mount Conversion Service
  • Rounded diaphragm
  • Designed to minimize flare and ghosting
  • High-precision, durable brass bayonet mount
  • Evaluation with SIGMA’s own MTF measuring system “A1”
  • Made in Japan
  • The lens barrel is engraved with the year of release

Last days to get Skylum Luminar AI with double discount.

More hand-picked deals are listed here.

Deal pages:

Refurbished lenses and DSLRs at Canon Store (best deals might be found here)

Save $10 on Luminar 4 and/or Aurora HDR 2019 and/or Luminar AI using our code “WATCH” at checkout.

Click here to open the rest of the article