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A patent for a new EF 300mm f/4L IS has appeared. Other optical formulas appearing in the patent are 24mm f/2.8 and 50mm f/1.3 with variable diffractive index elements which help correct some aberrations (thanks Keith).
Patent Publication No. 2015-28551 (Google Translated)
- Published 2015.2.12
- Filing date 2013.7.30
Example
| Example | Focal distance | Fno. | Half angle | Image height | Overall length of the lens | BF |
|---|---|---|---|---|---|---|
| One | 294.00 | 4.14 | 4.21 | 21.64 | 239.07 | 83.42 |
| Two | 24.48 | 2.86 | 41.47 | 21.64 | 92.00 | 38.00 |
| Three | 51.70 | 1.30 | 22.71 | 21.64 | 94.01 | 37.50 |
| Four | 294.00 | 4.14 | 4.21 | 21.64 | 240.00 | 82.95 |
| Five | 6.15 20.45 71.28 | 2.88 3.71 3.69 | 30.34 9.98 2.89 | 3.60 | 84.11 86.12 90.41 | 11.74 15.68 8.50 |
| Six | 293.97 | 4.14 | 4.21 | 21.64 | 239.98 | 85.34 |
Source: [Egami]
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