[Klaus]

EF-S 55-250mm f/4-5.6 IS STM

 

http://www.usa.canon.com/cusa/consumer/p...5_6_is_stm

 

Besides the new STM drive it also features a new optical design.

 

manufacturer MTFs:

http://cweb.canon.jp/ef/lineup/ef-s/ef-s...ec/mtf.png

 

vs old

http://cweb.canon.jp/ef/lineup/ef-s/ef-s...ec/mtf.png

 

And soon here in the zone. 

[Brightcolours]

And a very different optical design too... It went from a 12 elements 10 groups design to a 15 elements 12 groups design.

old:



new: