|
When you purchase through links on our site, we may earn an affiliate commission. Here's how it works. |
Canon files patent for new DO lenses
- Patent publication 2009-198960
- Published 03/09/2009
- Filing date 2008/02/25
Example 1
- Focal length f = 27.14mm
- Fno = 1.85
- Angle of 77.1 °
Example 2
- Focal length f = 24.50mm
- Fno = 1.45
- Angle of 82.9 °
Example 3
- Focal length f = 25.00mm
- Fno = 1.45
- Angle of 81.8 °
Example 4
- Focal length f = 24.33-36.50-47.00mm
- Fno = 3.4-4.0-4.7
- 83.3-61.3-49.4 ° angle
Example 5
- Focal length f = 26.00-39.00-50.23mm
- Fno = 3.4-4.0-4.7
- 79.5-58.0-46.6 ° angle
Information
- General retrofocus
- In general SLR wide angle lens
- Many chromatic aberration
- Using high-dispersion glass, as excessive compensation around
- General diffractive optics
- Can correct chromatic aberrations
- Where it is difficult to use
- Manufacturing difficulties
- Aberration can not fine-lattice
Patented Features
- Adopted retrofocus
- Chromatic aberration correction over the entire
- Diffractive optical elements, aspherical and low dispersion, employing anomalous dispersion lens
- The lenses focus mechanism
- Front lens is fixed
- Second lens to focus
- Floating mechanism
- The optical system of patents
- Lateral chromatic aberration to occur around the first lens
- Not easily corrected by increasing the number of lenses
- Diffractive optics correction to put the image side than the diaphragm
- Only increase the power of the diffractive optical element
- Chromatic aberration correction using a bonded lens
This is an older patent application, but I think it's still important to see diffractive optics are not dead within Canon R&D.
cr
