Cytat Zamieszczone przez dpreview.com@sigma interview

We describe it as having Fluorite equivalent characteristics. It's the most expensive optical glass but it's still cheaper and lighter than fluorite.' The FLD glass is comparatively soft and has to be polished carefully, adding to its cost but it does not have the temperature sensitivity traditionally associated with fluorite glass.
Te nowe szkła będą wymiatać!
BTW. Pogrubiłem powód dla którego telasy są białe.