Canon Patent: RF 70mm F2, RF 70mm F2.8, RF 75mm F2.4, and RF 85mm F2.8

Canon Patent

A new Canon patent application for relatively fast prime lenses.

Canon patent application 2023149130 (Japan, published 10/12/2023) discusses optical formulas for prime lenses for the RF mount:

  • RF 70mm F2
  • RF 70mm F2.8
  • RF 75mm F2.4
  • RF 85mm F2.8

From the patent literature:

  • The present invention provides an optical system that is small and lightweight, yet can satisfactorily correct various aberrations including chromatic aberration and obtain high optical performance, and an imaging device having the same.
  • BACKGROUND ART
    In recent years, there has been a strong demand for optical systems used in imaging devices to have a compact overall lens system and high optical performance including chromatic aberration correction.
  • Generally, in a telephoto type optical system, as the focal length becomes longer, the entire lens system becomes larger and its mass increases. In order to miniaturize the optical system with a telephoto power arrangement, it is effective to strengthen the positive refractive power on the object side and the negative refractive power on the image side, but it is effective to increase the positive refractive power on the object side and the negative refractive power on the image side. Challenges arise in balancing both work and life.
  • Furthermore, in an optical system compatible with a large image sensor, it is important to perform focusing quickly using a small and lightweight lens group, and with less burden on the driving device. In a telephoto optical system, in order to easily perform focusing and to reduce aberration fluctuations during focusing, it is important to appropriately set the lens configuration of each lens group.
  • Patent Document 1 discloses that a first lens group with positive refractive power, a second lens group with negative refractive power, and a third lens group are arranged in order from the object side to the image side. An optical system is disclosed in which the distance between matching lens groups is varied.
  • However, in the optical system described in Patent Document 1, the number of lenses constituting the optical system is large, and the optical system cannot be sufficiently miniaturized.
  • The present invention provides an optical system that is small and lightweight, yet can satisfactorily correct various aberrations including chromatic aberration and obtain high optical performance, and an imaging device having the same.

Example 1

  • Focal length: 70.00
  • F value: 2.06
  • Half angle of view: 17.17
  • Image height: 21.64
  • Total length: 78.88
  • Back focus: 16.48

Example 2

  • Focal length: 70.00
  • F value: 2.83
  • Half angle of view: 17.17
  • Image height: 21.64
  • Total length: 68.97
  • Back focus: 17.41

Example 3

  • Focal length: 85.00
  • F value: 2.83
  • Half angle of view: 14.28
  • Image height: 21.64
  • Total length: 83.01
  • Back focus: 17.55

Example 4

  • Focal length: 75.00
  • F value: 2.40
  • Half angle of view: 16.09
  • Image height: 21.64
  • Total length: 86.00
  • Back focus: 15.64

More Canon patents are listed here.

[via asobinet]

Canon Patent: RF 70mm F1.8 STM Lens For EOS R System

Canon Patent

A new Thursday, a new Canon patent. Not surprising yet another one for the RF mount. The whole thing was spotted by asobinet.com.

Canon patent application 2021-131499 (Japan) discusses optical formulas for what appears to be an RF 70mm f/1.8 STM lens for Canon’s full frame mirrorless system EOS R. From the patent literature:

PROBLEM TO BE SOLVED

To provide a compact, lightweight and large-diameter optical system.

Patent Document 1 describes a double-Gauss type optical system capable of correcting various aberrations with a small number of lenses

However, the double-Gauss type optical system as disclosed in Patent Document 1 satisfactorily corrects various aberrations such as spherical aberration and curvature of field when the symmetry is broken due to miniaturization. Becomes difficult. In particular, when the optical system has a large aperture ratio, it becomes difficult to suppress sagittal flare and coma flare at an intermediate angle of view.

Therefore, an object of the present invention is to provide an optical system and an image pickup apparatus having high optical performance while being compact and having a large aperture ratio.

Embodiment 1:

  • Focal length 49.57
  • F number 1.85
  • Half angle of view 23.58
  • Image height 21.64
  • Lens overall length 59.59
  • BF 25.67

Embodiment 2:

  • Focal length 70.00
  • F number 1.85
  • Half angle of view 17.17
  • Image height 21.64
  • Lens overall length 83.52
  • BF 36.62

According to asobinet, the lens discussed in the patent literature has an optical design similar to the RF 50mm F1.8 STM. Maybe it is another excellent performer at an affordable price.

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

Deal: Sigma 70mm f/2.8 DG ART Macro – $479 (reg. $569, today only)

Sigma 70mm F/2.8

It’s Black Friday time so there will be more deal posts than usual. Apologies to those not interested. Here is a Sigma 70mm f/2.8 DG ART Macro deal.

Only for today (11/23/20) Adorama has the Sigma 70mm f/2.8 DG ART Macro on sale at $479. Compare at $569.

At a glance:

  • Mount with dust- and splash-proof design*
  • Rounded diaphragm
  • Fast AF with full-time manual override
  • Compatible with SIGMA MOUNT CONVERTER MC-11
  • Available SIGMA USB DOCK makes customization and flexible adjustment possible
  • Brass bayonet mount
  • “Made in Japan” with outstanding craftsmanship

More hand-picked deals are listed here.

Get 20% off handmade Hyperion camera straps with code BlackFriday, or use BlackFridayBuy3 to buy three straps and get the forth for free.

Today’s Gold Box and one day only deals at Amazon USAmazon DEAmazon UKB&H Photo, eBayAdorama.

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

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

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Sigma 70mm F/2.8 DG Macro Art Lens Review (DPReview)

Sigma 70mm F/2.8 DG Macro Art

Sigma 70mm F/2.8 DG Macro Art at a glance:

  • EF-Mount Lens/Full-Frame Format
  • Aperture Range: f/2.8 to f/22
  • Two FLD Elements, Two SLD Elements
  • Low Dispersion and Aspherical Elements
  • Super Multi-Layer Coating
  • 1:1 Magnification, 10.2″ Min. Focus
  • Coreless DC AF Motor, Manual Override
  • Weather-Sealed, Brass Bayonet Mount
  • Rounded 9-Blade Diaphragm
  • Compatible with Sigma USB Dock

DPReview TV’s Chris and Jordan test Sigma’s latest macro lens, the 70mm F2.8 DG Macro Art. Find out why they like it.

Sigma 70mm F/2.8 DG Macro Art:

America: B&H Photo, 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

Sigma 70mm f/2.8 Macro ART Review (D. Abbott)

Sigma 70mm F/2.8 DG Macro Art

Sigma 70mm f/2.8 Macro ART at a glance:

  • EF-Mount Lens/Full-Frame Format
  • Aperture Range: f/2.8 to f/22
  • Two FLD Elements, Two SLD Elements
  • Low Dispersion and Aspherical Elements
  • Super Multi-Layer Coating
  • 1:1 Magnification, 10.2″ Min. Focus
  • Coreless DC AF Motor, Manual Override
  • Weather-Sealed, Brass Bayonet Mount
  • Rounded 9-Blade Diaphragm
  • Compatible with Sigma USB Dock

Dustin Abbott completed his comprehensive review of the Sigma 70mm f/2.8 Macro ART lens.

From the conclusion;

[…] the Sigma 70mm f/2.8 Macro | ART is a somewhat quirky lens.  It deviates from the path established for the ART series on a number of levels, and also deviates from the modern standard of what a macro lens should have (Image Stabilization, Internal Focus, etc…)  The one area where it is very much a Sigma ART lens is in the optical performance, where it delivers as good a performance as I’ve seen from a macro lens outside of bokeh that is a little busy in some situations.  I’m less impressed by the decision about the focus motor, at least on DSLRs […]

Dustin Abbott’s review comes with a huge set of sample pictures and analyses all aspects of the Sigma 70mm f/2.8 Macro ART. For those who prefer to watch, the video review below tells everything.

Sigma 70mm f/2.8 Macro ART: B&H Photo | Adorama | Amazon

Sigma 105mm F1.4 DG HSM Art and 70mm F2.8 DG Macro Art get Hot One Awards from Professional Photographer

Sigma 105mm F1.4

Sigma press release:

Sigma 70mm F2.8 DG Macro Art and 105mm F1.4 DG HSM Art Lenses Honored with Hot One Awards from Professional Photographer

Two of Sigma’s Art lenses join this year’s buyers’ guide showcasing the year’s best and most innovative technology products for professional photographers

Ronkonkoma, New York — August 1, 2018 – Sigma Corporation of America, a leading camera, DSLR lens, flash and accessories manufacturer, today announced that two of its newest Art lenses, the 70mm F2.8 DG Macro ($569; available in Canon, Sigma and Sony E mounts) and 105mm F1.4 DG HSM, the “Bokeh Master” ($1599; available in Canon, Nikon, Sigma and Sony E mounts), have been honored with Professional Photographer 2018 Hot One Awards. The annual Hot One Awards are given to innovative, exciting and inspiring technology products for photographers. Winners will appear in the August issue of Professional Photographer and also in a featured gallery beginning August 1st on the Professional Photographer website.

Sigma 105mm f/1.4 DG HSM Art: B&H Photo | Adorama | Amazon

Sigma 70mm F2.8 DG Macro Art: B&H Photo | Adorama | Amazon

Professional Photographer is the official magazine of Professional Photographers of America, the largest international non-profit association for professional photographers. For more than 100 years, it has worked to help the pros advance their businesses and careers through editorial content that addresses the artistic, technological and business aspects of their work. This year marks the 19th Hot One Awards, and award recipients are more exciting and groundbreaking than ever before.

To see the full list of Hot One Award winners, please visit www.PPmag.com.

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