That’s what a Canon patent application seems to suggest, a 300mm f/2.3 mirror lens. Read on.
Canon patent application 2023013456 (Japan, published 1/26/2023) discusses optical formulas for a 300mm f/2.3 mirror lens with autofocus. From the patent literature:
An optical system capable of sufficiently correcting curvature of field while being compact, lightweight, and having a large aperture ratio is provided.
Description of the Related Art
As a telephoto imaging optical system having a long focal length, there is a catadioptric imaging optical system having a reflective system and a refracting system. In such a catadioptric imaging optical system, Patent Literatures 1 and 2 disclose an inner focus type imaging optical system that is compact, lightweight, has a large aperture ratio, and has an autofocus function. ing. However, in the imaging optical systems disclosed in Patent Documents 1 and 2, the configuration of the reflection system cannot sufficiently correct the curvature of field.
SUMMARY OF THE INVENTION
The present invention provides an optical system capable of sufficiently correcting curvature of field while having a small size, light weight, and large aperture ratio.
An optical system as one aspect of the present invention has a first group that does not move during focusing and a second group that moves during focusing.
- Focal length: 298.89
- F-value: 2.28
- Half angle of view: 4.14
- Image height: 21.64
- Overall length: 177.20
- Back focus: 65.95
- Focal length: 408.04
- F-value: 5.00
- Half angle of view: 3.04
- Image height: 21.64
- Total length: 189.17
- Back focus: 47.69
More Canon patent applications are listed here. Some particularly interesting patent applications we think might get into production are these:
- RF 16-28mm lens with either f/2.8, f/2.8-4, or f/4
- 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