A patent for a new Canon EF 400 f/4 DO IS has appeared. The current lens has been around since December, 2001 and I think it's a gem in the Canon lineup.
We've seen a lot of DO patents over the years, but no DO lens has been announced since June, 2004 when the EF 70-300 f/4.5-5.6 DO IS came to market.
- Patent Publication No. 2014-109700
- Publication date 2014.6.12
- Filing date 2012.12.3
- Example 1
- Focal length f = 392.00-381.59-332.99mm
- Half angle ω = 3.16-3.10-2.81 °
- Image height Y = 21.64mm
- The overall length of the lens 292.02mm
- BF 105.64mm