Canon Patent Application: Canon EF-S 55-250mm
While never as exciting as the latest full frame lens patent applications as we discover, the EF-S system (and closely followed by the EF-M system these days) is the backbone of Canons camera sales. Thus, while research and development happen on the more exciting areas, work still progresses on the more mundane, yet necessary lenses.
This patent application discusses a lens that is compact, lightweight and highly corrected for axial and normal chromatic abberations.
This lens has a long backfocus and a 13.66mm image radius (image height), so it's an EF-S APS-C lens.
Focal distance 56.81 135.00 241.28
F number 4.03 5.11 5.88
Field angle 13.52 5.78 3.24
Image height 13.66 13.66 13.66
length of the lens 154.60 192.00 209.61
BF 38.74 60.94 75.27
Japan Patent Application 2018-194772
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