Egami has discovered a new patent filed by Canon. The new patent describes diffractive optical (DO) lenses of the EF 100-400 f/4.5-5.6 DO and EF 70–300mm f/4.5–5.6 DO IS USM.
Canon lenses which feature the diffractive optical (DO) are smaller and lighter compared to the same focal length lenses but the price becomes generally higher when the lenses have optical formual for DO.
The current EF 100-400mm f/4.5-5.6L IS USM telephoto lens is available for $1,499 at Amazon. The company is also rumored to announce EF 100-400mm f/4.5-5.6L IS II lens in August.
Canon Patent for EF 100-400mm f/4.5-5.6 DO Lens
EF 100-400 f/4.5-5.6 DO
- Patent Publication No. 2014-89385
- Publication date 2014.5.15
- Filing date 2012.10.31
- Example 1
- Zoom ratio 3.78
- Focal length f = 103.00-200.00-388.94mm
- Fno. 4.63-5.24-5.83
- Half angle ω = 11.86-6.17-3.18 °
- Image height Y = 21.64mm
- 228.82-273.58-303.10mm total length
- BF 69.48-90.93-105.73mm
- Example 6
- Zoom ratio 4.00
- Focal length f = 72.50-135.00-289.99mm
- Fno. 4.44-5.04-5.85
- Half angle ω = 16.62-9.10-4.27 °
- Image height Y = 21.64mm
- 143.91-177.69-203.15mm total length
- BF 39.10-39.10-39.10mm
via EG
