[cbope]

I found a pretty significant difference between the kit DA 18-55 WR @18 and DA* 16-50 @16, that 2mm really does make a difference in field of view.

Think about it this way, 18mm is 27mm full-frame equivalent, very close to 28mm. 16mm is equivalent to 24mm on full frame. Back in the 35mm film SLR days, you had separate 24mm and 28mm as standard wide angles on basically every system, and the difference in field of view was significant enough to justify each lens.