1)I have problem with the horizon - it is not level. When trying to calibrate - the camera moves 180, then falls, I see «gimbal roll reached end point». I have the latest firmware.

2)The copter moves 360 degrees very fast, faster then my Inspire 1 PRO. How to fix this?

3)What advice will you give to work with DNG? what color profile to use? How better to do color correction in DaVinci Resolve?

4)Is it OK to Use the beta version of the firmware for OSMO? When will we see the new firmware?

For your first question, I requested more information in your duplicate thread:

http://forum.dji.com/thread-59862-1-1.html

If you want to adjust the speed of the yaw movement, you would need to adjust your yaw EXPO settings to make it less sensitive. Regarding your BETA question, you should contact info@dji.com to get more information on using BETA firmware across various platforms.