A new Canon patent application, published on April 28, 2025, outlines several interesting optical system…
Canon Files Patent For New Primes (45mm, 50mm, 60mm)


Egami spotted another patent filed by Canon. The patent refers to s 50 mm F1.4 , 50 mm F1.2 , 45mm F1.6 and 60 mm F1.8 lenses, and describes an apochromatic design that aims to reduce chromatic aberration.
Patent description (machine translated):
- Patent Publication No. 2013-57802
- 2013.3.28 Release Date
- 2011.9.8 filing date
- Example
Example Focal length Fno. Angle of view Focus One 51.7 1.45 45.4 Floating rear focusing + Two 51.7 1.45 45.4 Fed whole Three 51.7 1.25 45.4 Floating rear focusing + Four 51.7 1.25 45.4 Fed whole Five 45.0 1.6 51.4 Fed whole Six 60.0 1.85 39.7 Fed whole - In many large-diameter Gaussian secondary spectrum of axial chromatic aberration
- This problem occurs when using glass and others with the same Abbe number, a lens that is different partial dispersion ratio
- When used in a positive lens lanthanum flint glass small partial dispersion ratio
- When used in a negative lens of flint glass titanium large partial dispersion ratio
- Canon patent
- Using a lens with a partial dispersion ratio appropriate correcting the axial chromatic aberration secondary spectrum
- The concave lens surface adjacent to the aperture, coma aberration correction, the sagittal flare