Canon 85mm f/1.2 , 85mm f/1.8 , 135mm f/2 , 50mm f/1.4 Lens Patent

Egami has discovered new patents filed by Canon. The new patents is for prime lenses range of 50mm, 85mm and 135mm.

Patent includes Canon 85mm f/1.2, 85mm f/1.8, 135mm f/2 and 50mm f/1.4 lenses and the use of glass with anomalous dispersion.

Below are the details of these new Canon prime lenses translated by Google.

Patent Publication No. 2013-114133
- Publication date 2013.6.10
- Filing date 2011.11.30

Example

embodiment
	Focal length	Fno.	The overall length of the lens	BF	Lens constitution
One	85.00	1.24	122.56	38.35	10 pieces of six groups
Two	83.30	1.80	116.11	39.11	10 sheets in 7 groups
Three	132.30	2.06	162.67	43.23	10 sheets in 7 groups
Four	51.70	1.41	87.84	38.94	7 group nine

Image height Y = 21.64mm

Factors that chromatic aberration of magnification chromatic aberration or axial chromatic aberration occurs
- Reducing the total length
- Focal length for a long time
Glass material Abbe number 70-90, of 1.4-1.5 refractive index
- Possible correction of axial chromatic aberration
- Must increase a curvature, spherical aberration and curvature of field is generated
Canon patent
- I use a glass material having an anomalous partial dispersion of the predetermined
- Consisting of organic and inorganic compound

via: Egami

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