see also:

• Canon EF lenses
• Canon EF 400mm f/4 DO IS II USM

• designed in 1993, this is one of the lenses which gave Canon the lead over Nikon with its relatively fast USM AF capability and excellent optics and build quality
• it is reasonably affordable and popular with birders but lacks image stabiliser and thus requires use of a tripod
• most people would be better off with the Canon EF 100-400mm f/4.5-5.6L IS II USM

Image courtesy of Ken Rockwell

• 400mm f/5.6
• metal build
• not fully weather sealed only moisture seal on lens mount
• close focus 3.5m giving 0.12x macro on full frame
• 8 straight blades
• 7 elements in 6 groups including one S-UD and one UD element
• removable tripod collar
• 77mm filter
• dual manual focusing rings
• focus limiter switch allowing focus range to be limited to 8.5m-∞ or 3.5m-∞
• 3.5 x 10.1“ (88.9mm x 256.5 mm)
• 2.75 lb (1.25 kg)
• $US1249

• http://www.kenrockwell.com/canon/lenses/400mm-f56.htm
• https://luminous-landscape.com/forgotten-400/
• http://slrgear.com/reviews/showproduct.php/product/167
• http://www.photozone.de/Reviews/173-canon-ef-400mm-f56-usm-l-lab-test-report--review
• http://www.photozone.de/canon_eos_ff/612-canon400f56ff