Nikon announced the 400mm f/2.8E FL
ED VR lens. It's an update, but not a MkII version – it receives the designation FL because it now contains two fluorite elements. So Nikon's new lens incorporates something that Canon has been using for many, many years. Woo hoo.
Even more interesting, check out Nikon's updated glossary. There's now an entry for fluorite (FL)
touting it's advantages, but apparently they forgot to update their entry for ED glass
, clearly intended to bash Canon's use of fluorite, where they state, "In the past, correcting this problem for telephoto lenses required special optical elements that offer anomalous dispersion characteristics - specifically calcium fluoride crystals. However, fluorite easily cracks and is sensitive to temperature changes that can adversely affect focusing by altering the lens' refractive index.
" Despite that easy cracking and adverse effects on focusing, they're now saying it's great for their telephoto lenses.
Make up your minds, Nikon…or at least pay attention to your own ad-speak.