|Canon EF 800mm f/5.6L IS lens|
My readers know I am a fan of Canon's Diffractive Optics technology. The current EF 400mm f/4 DO IS II is my favorite Super Telephoto lens when I want to travel light on my wildlife photography tours. You can see my equipment bag and works on MichaelDanielHo.com. Canon has been working to perfect the DO technology since the first EF 400mm f/4 DO IS lens came out in 2001. The EF 600mm f/4 DO BR lens was showcased in last year's Canon EXPO at New York City.
In April, a new Canon DO patent has been uncovered for the APS-C sensor. The new design has a focal length of 50-300mm f/4.5-6 with STM. The current EF 800mm f/5.6L IS is Canon longest Telephoto lens. It is heavy and the technology is aging. Canon has been toying with the ideal of replacing it with a Series II model. But now another DO patent has been discovered by Egami. It is the EF 1000mm f/5.6 DO IS lens.
This will be ultimate in Super Telephoto Diffractive Optics design. If Canon can bring this lens out with a top weight of around 8 to 9 pounds and pack it with the latest DO BR technology, I will be a buyer for sure. Nikon saw the value in DO lens design last year but is much further behind than Canon in this technology. They announced the Phase Fresnel (PF) 300mm f/4 lens in January 2015. Fresnel lenses were originally developed by the French physicist, Augustin-Jean Fresnel for use in lighthouses.
Patent Publication No. 2016-102852 (Google Translated)
- Published 2016.6.2
- Filing date 2014.11.27
- Zoom ratio 1.00
- Focal length 950.00
- F-number 5.80
- Angle of view 1.30
- Image height 21.64
- Overall length of the lens 485.94
- BF 0.40
- Canon patent
- Positive and negative Shibomake
- Diffractive optical element (first group)
- Inner focus (the second group)