http://news.ricoh-imaging.co.jp/rim_info2/2016/20161117_013083.html
Expanded functions:
1. Red-Lighted LCD Monitor Display Function
The PENTAX K-1 provides a red-lighted LCD monitor display function, which prevents the pupils of the photographer's eyes from constricting after they have become accustomed to a dark environment during astrophotography.
2. Bulb Timer Function
The bulb timer function comes in handy when photographing celestial bodies or fireworks. The PENTAX K-1 allows the photographer to expand the exposure time up to 20 minutes in Bulb mode.
3. Others
During slow shutter speeds the PENTAX K-1 features white dot noise reduction processsing.*
Overall Improved stability for general performance.
* When Slow Shutter Speed NR is OFF and JPEG image.