Patent: Canon EF 35 f/1.4L II

Canon EF 35 f/1.4L Patent
A new patent for a 35mm f/1.4 optical formula has appeared. This is the first to appear since 2011 in regards to an updated 35 f/1.4L. View the previous patent here.

Patent Publication No. 2012-123155

• 2012.6.28 Release Date
• 2010.12.8 filing date

Example 1

• Focal length f = 34.73mm
• Fno. 1.45
• Half angle of 31.92 deg.
• Image height 21.64mm
• Length 128.11mm lens
• 38.48mm back focus
• An effective diameter of 52.03mm lens
• Effective diameter aperture 25.52mm
• Lens Construction 12 elements in 9 groups sheet
• 2 2 aspherical surface
• 2 UD glass sheet

Retrofocus

• And retro focus lens optical system focal length is shorter than the length of the optical system
• Increasingly asymmetric refractive power arrangement must be strengthened a negative refractive power of the front group in particular
• Coma aberration, astigmatism, spherical aberration occurs
• Order to secure a back focus must be to increase the ratio retro

Source: [EG]

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