Here is a very interesting Canon patent application, once more for an RF mount lens. An RF 28-70mm f/2.8L with inner focusing and that does not extend might be in the works.

The Canon patent application spotted by asobinet.com (they did not disclose the patent number), discusses optical formulas for a RF 28-70mm f/2.8L lens. The interesting part, if I got it right from the machine translated Japanese text, is that the lens not only does all the focusing but also employs a design that is usually found on wide-angle lenses.

It sounds like a patent for a small and lightweight standard zoom. The characteristic of this optical system is that the total length is the longest at the wide-angle end and the total length becomes shorter toward the telephoto end. This is a common optical system for wide-angle lenses, but I don’t see this type of lens with standard zoom lenses, especially with large-aperture zoom lenses. If it is really put into practical use, it will be a very portable lens.

Did I get it right? The lens is indeed described to be shorter at the telephoto end (emphasis mine) in both embodiment:

• Wide-angle intermediate telephoto
• Focal length 28.84 36.81 67.90
• F number 2.91 2.91 2.91
• Half angle of view (°) 32.68 29.23 17.67
• Image height 18.50 20.60 21.64
• Lens total length 117.09 109.31 101.58
• BF 9.99 13.47 21.59

• Focal length 28.84 37.17 67.90
• F number 2.91 2.91 2.91
• Half angle of view (°) 32.65 28.90 17.67
• Image height 21.64 21.64 21.64
• Lens total length 132.62 122.81 111.18
• BF 21.92 26.79 39.84

Moreover, the lens uses a floating focus structure to achieve autofocus. That means it might have very fast and and highly responsive AF. The patent literature is very clear in what should be achieved:

PROBLEM TO BE SOLVED: To provide a zoom lens having a short overall lens length, being compact and lightweight, and having high optical performance.

All comments welcome.

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

• Automatic shutter silencing based on subject and distance
• A bunch of prime lenses for the RF mount
• An improved Electronic Viewfinder
• Patent application for RF 50mm F1.4 and an RF 35mm f/1.4 lenses
• A zoom lens that might be for an EOS R with APS-C sensor
• A smaller IBIS unit.
• A cooling adapter for the RF mount (R5 overheating?)
• A bunch of macro lenses for the RF mount.
• A 8mm f/4 circular fisheye lens for the Canon EOS R system
• A battery grip that works with differently siszed cameras
• A 100-400mm f/5.5-7.1 lens for APS-C cameras. EOS M or DSLR?
• RF 17-70mm lens for EOS R system
• IBIS coming to the EOS M and PowerShot lineup?
• Patent Application: mirrorless camera with large display and virtual control wheel
• Patent Application: IBIS and Lens IS Working Together
• Patent application for high speed mirror movement and control
• Patent application for an RF 14-28mm f/2 lens
• Patent application for an RF 50mm f/1.8 lens
• Patent application for a smart lens cap
• Patent application for celestial auto-focus
• Patent application describing a Pop-Up Flash With LED
• Patent application describing the optical formula for a RF 70-300mm F/4-5.6 IS lens for EOS R systems
• Patent application describing how to improve burst rate by compressing raw files
• Patent application describing a new way to review photos from a sequential shot
• Patent application that describes technology to improve wireless communication while reducing power consumption
• Patent application to spot and reduce moire artefacts in image data
• Patent application for weather sealed lens adapter
• Patent application for AI powered predictive camera control system
• Patent application for 18-55mm kit lens with LCD display
• Patent application to reduce noise in image files