Canon Patent: 300mm f/2.8, 400mm f/2.8 And 600mm f/4 With Built-in Teleconverter

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A new Canon patent for telephoto lenses with built-in teleconverter. For what mount? RF mount.

Canon patent 2022142979 (Japan, published 10/3/2022) discusses optical formulas for three telephoto lenses with built-in teleconverter. The lenses are 300mm f/2.8, 400mm f/2.8 and 600mm f/2.8. From the patent literature (machine translated):

An object of the present invention is to provide an optical system having a variable power optical system that is inserted into and removed from a main optical system, and to achieve good optical performance while reducing the weight of the entire system.

Description of the Related Art

As a method for changing the focal length of an optical system used in an imaging apparatus, there is a converter method that changes the focal length of the entire system by inserting a variable magnification optical system (extender) in the optical path.

When adopting a system incorporating a variable magnification optical system, in order to achieve good optical performance while reducing the weight of the entire system including the variable magnification optical system, the insertion position of the variable magnification optical system must be appropriately selected. It is important not only to do so, but also to properly configure the main optical system. The invention disclosed in Patent Document 1 has room for improvement from the viewpoint of achieving both weight reduction and optical performance.

Summary of the invention

It is an object of the present invention to achieve good optical performance while reducing the weight of the entire system in an optical system having a variable magnification optical system that is inserted into and removed from a main optical system.

Example 1 ML

  • Focal length: 389.00
  • F-value: 2.91
  • Half angle of view: 3.18
  • Image height: 21.64
  • Total length: 406.00
  • Back focus: 53.83

Example 1 with teleconverter

  • Focal length: 544.00
  • F-value: 4.19
  • Half angle of view: 2.28
  • Image height: 21.64
  • Overall length: 406.01
  • Back focus: 53.83

Example 2 ML

  • Focal length: 582.00
  • F-value: 4.12
  • Half angle of view: 2.13
  • Image height: 21.64
  • Overall length: 486.10
  • Back focus: 81.91

Example 2 with teleconverter

  • Focal length: 814.80
  • F-value: 5.88
  • Half angle of view: 1.52
  • Image height: 21.64
  • Overall length: 486.10
  • Back focus: 81.91

More Canon patents are listed here.

[via asobinet]

Canon Patent: 400mm f/2.8, 500mm f/4 & 600mm f/4 For The EOS R System

Canon Patent
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Ready for the start of the week, here is a new Canon patent application for RF mount lenses.

A new Canon patent application discusses optical formulas for three RF mount lenses:

  • 400mm f/2.8
  • 500mm f/4
  • 600mm f/4

PROBLEM TO BE SOLVED: To obtain an optical system which is lightweight and has chromatic aberration and other aberrations satisfactorily corrected.

Example 1

  • Focal length: 392.00
  • F value: 2.90
  • Half angle of view: 3.16
  • Image height: 21.64
  • Overall length: 360.03
  • Back focus: 31.01

Example 2

  • Focal length: 490.00
  • F value: 4.12
  • Half angle of view: 2.53
  • Image height: 21.64
  • Overall length: 412.08
  • Back focus: 33.39

Example 3

  • Focal length: 588.00
  • F value: 4.12
  • Half angle of view: 2.11
  • Image height: 21.64
  • Overall length: 476.08
  • Back focus: 33.21

This patent application might indeed lead to lenses that will be on sale one day.

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

Canon Patent: 400mm f/4 DO IS Extender 1.4x and 600mm f/4 IS Extender 1.4x

Canon Patent
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A new Canon patent application was spotted. 400mm f/4 DO IS Extender 1.4x and 600mm f/4 IS Extender 1.4x are discussed.

Canon patent application 2022-22771 discusses optical formulas for two rather interesting lenses:

  • 400mm f/4 DO IS Extender 1.4x
  • 600mm f/4 IS Extender 1.4x

PROBLEM TO BE SOLVED: To provide an optical system in which a magnification conversion optical group can be inserted and removed and the total length is short.

As a method of changing the focal length of the optical system used for imaging, there is a method of inserting a magnification conversion optical group such as an extender into the optical path . Further, as an optical system in which the total length (distance from the optical surface on the object side to the image surface) does not change due to the insertion / removal of the magnification conversion optical group, Patent Document 1 describes the axial light beam between the aperture stop and the image surface. An optical system capable of inserting and removing a magnification conversion group at a converging position is disclosed.

However, if a space for inserting the magnification conversion optical group is provided between the aperture diaphragm and the image plane as in Patent Document 1, the total length of the original optical system becomes long . Further, if the magnification conversion optical group is inserted in a narrow space, various aberrations of the optical system may increase. The
present invention provides an optical system in which a magnification conversion optical group can be inserted and removed, but the total length is short and good optical performance can be obtained.

Example 1

  • Focal length: 392.58
  • F value: 4.12
  • Half angle of view: 3.15
  • Image height: 21.64
  • Overall length: 280.33
  • Back focus: 36.01

Example 1 (with inserted teleconverter)

  • Focal length: 549.72
  • F value: 5.77
  • Half angle of view: 2.25
  • Image height: 21.64
  • Overall length: 280.33
  • Back focus: 36.00

Example 5

  • Focal length: 585.00
  • F value: 4.12
  • Half angle of view: 2.12
  • Image height: 21.64
  • Overall length: 467.45
  • Back focus: 55.50

Example 5 (with inserted teleconverter)

  • Focal length: 819.18
  • F value: 5.77
  • Half angle of view: 1.51
  • Image height: 21.64
  • Overall length: 467.45
  • Back focus: 55.50

The Canon 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:

Olympus 300mm f/4 vs Canon RF 600mm f/11 – FF vs 4/3 Comparison

Olympus 300mm
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Somewhat unusual yet rather interesting comparison between the Olympus 300mm f/4 and Canon RF 600mm f/11 lenses.

Our friends at Mirrorless Comparison compared the Olympus 300mm f/4 and Canon RF 600mm f/11 lenses for wildlife and bird photography. The former is for Micro Four Thirds and the latter for full frame. From their conclusion:

Traditionally, micro four thirds has always been the system we mention when talking about travelling light and reducing size and weight. On the other hand, full frame is supposed to be the system with the big heavy lenses, but also superior image quality. Well, in our case here, some of these claims can be challenged (with a few catches).

The RF 600mm F11 (and 800mm F11) is a brilliant idea from Canon. I was interested when they announced it, then I was skeptical about the aperture, but now I’m happy to say I really enjoyed taking pictures with this lens, and I quickly forgot about the slow aperture. I was using something very light, with excellent quality, autofocus and stabilisation. I thought there would be more tradeoffs than that.

[…]

Where does that leave the Olympus solution then? Well, rest assured, it is still a very strong competitor. The faster aperture of the 300mm Pro easily makes up for the smaller sensor, you get a premium build quality with weather sealing, state of the art stabilisation and a few welcome features like being able to focus much closer to small subjects, which adds to the lens’ versatility.

Read the review at Mirrorless Comparison

More comparison reviews are listed here.

Canon RF 600mm f/11 vs RF 800mm f/11Comparison Review

Rf 800mm F/11
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More review stuff about the “quirky” Canon RF 600 f/11 and RF 800 f/11 lenses for the EOS R mount.

Mirrorless Comparison posted their Canon RF 600 f/11 and RF 800 f/11review. From Mat’s conclusion:

I enjoyed using the RF 600mm F11 and RF 800mm F11 more than I had originally anticipated. I thought the F11 aperture and limited focus area would be too much of a trade-off, but I was wrong.

Surely if the clouds are too dark or you’re in the shade of a woodland in rainy conditions, you will struggle to compensate for that slow aperture. The converters (1.4x and 2x) will raise the challenge further because the aperture becomes f/16 and f/22 respectively.

But there are also many situations where f/11 will be enough, and you’ll be able to walk around a nature reserve or hike in the mountains with a lightweight solution, something you can’t say every day about full frame lenses for wildlife photography.

You’ll be glad to hear that the 600mm and 800mm are very sharp, the optical stabilisation is excellent and the autofocus delivers very good performance, despite the limited area available. For the price you pay, you can get a lot out of these two lenses.

My strongest criticism is the lack of weather sealing. I understand that these are non-L lenses designed for amateurs, but they’re also two lenses that photographers will use outdoors 99% of the time. It would be great to be able to walk around without worrying about light rain or a bit of dust. It is also annoying to have to buy the lens hood separately.

Read the review at Mirrorless Comparison…

Mirrorless Comparison’s review comes with plenty of test shots and talks about all the important things. Definitely worth a read. More comparison reviews are listed here.

Also interesting: an interview with the engineers who developed these lens. Also, Canon already said there will be more such lenses. For more Canon RF 800mm f/11 and RF 600mm f/11 review stuff have a look here.

Canon RF 600mm f/11

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 RF 800mm f/11

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

Image © mirrorlesscomparison.com. used with permission
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Canon RF 600mm f/11 IS STM Review (quirky and functional, D. Abbott)

Canon Rf 600mm F/11 Review
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Here is a Canon RF 600mm f/11 IS STM review by one of the less noisy and flashy and more serious reviewers out there. One of my top favorite reviewers.

RF 600mm f/11 IS at a glance:

  • RF-Mount Lens/Full-Frame Format
  • Fixed f/11 Aperture
  • Retractable, Locking Lens Barrel
  • Gapless Dual-Layer Diffractive Optics
  • STM Stepping AF Motor
  • Optical Image Stabilizer
  • Customizable Control Ring
  • Compatible with RF Extenders

Dustin Abbott posted his exhaustive Canon RF 600mm f/11 IS STM review. From his conclusion:

It is rare that I refer to a Canon lens as “quirky”, but both the Canon RF 600mm f/11 IS STM and Canon RF 800mm f/11 IS STM telephoto primes definitely qualify as quirky.  Canon’s engineers were willing to overlook a number of typical design conventions and niceties to produce functional telephoto primes with massive reach and good performance at bargain prices.  Used in the right conditions, either of these lenses is perfectly capable of producing stunning images.

But those quirks do help define the lens, however.  The loosen, extend, and tighten nature of getting the lens ready to shoot will result in some missed shots.  The small maximum aperture means that this is a lens designed for very specific (read:  bright!) lighting conditions, and so the opportunities to take full advantage of the stellar optics are limited by that physical reality.

But what other 600mm prime lens can you get for less than $700 USD?  Particularly one with good autofocus, effective image stabilization, and a solid optical performance?  That is a very, very short list, so while I know that this is a niche product for a niche audience, I’m glad that the RF 600mm F11 IS STM lens exists.

Read the review at Dustin Abbott’s site…

As usual the review comes with a huge set of sample pictures, comparison charts, and all the information you might want to know. Dustin’s reviews are what I look for when I am about to purchase new gear. And for those who prefer to watch their reviews, Dustin Abbott provides a comprehensive video-review (below).

More gear reviews by Dustin Abbott are listed here. You can follow Dustin Abbott on Twitter, YouTube, or on his website.

Also interesting: an interview with the engineers who developed these lens. Also, Canon already said there will be more such lenses. For more Canon RF 800mm f/11 and RF 600mm f/11 review stuff have a look here.

Canon RF 600mm f/11 IS STM

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 RF 800mm f/11 IS STM

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

Click here to open the rest of the article