I recall the old post by the Pentax Rumors about the various new DA 16-50/2.8 lens designs and patent(s) for improved performance, one of which (amongst 10 nos.) would be selected by Pentax for this new lens. Which will they use finally? 16 elements in 13 groups (5 designs), 17 elements in 13 groups (3 designs), 15 elements in 12 groups (two designs)? We shall know by the next year of 2021. :-)
