http://www.ricoh-imaging.co.jp/english/support/digital/k1.html
Changes to V1.20:
- Corresponded to [KAF4 lens mount] that is equipped with an electromagnetic diaphragm control system.
- Enable new lens HD PENTAX-DA 55-300mmF4.5-6.3ED PLM WR RE to shoot stable by updating firmware.
- Improved stability for general performance.