Ok it will only work in manual mode on K10 but what I did years back foe another lens I had I actually made a chart for it distance f stops and shutter speed I started with a chart from another ring flash then once I established a setting for one position f stop and shutter speed it was pretty easy to work out the rest by just going up and down the scale and I made 3 copies of that and it worked excellent for that ring flash. Don't ask me to do it again that was 20 years ago but if your on the edge with your photography you could make one. I used spread sheets to make the table and fill in all the numbers this one won't work right for 080c but it will give you a base to make your own chart once you get one or two setting correct its only a matter of changing the values by an equal amount each time. good luck with it. or google pentax 080c ring flash chart.
---------- Post added 11-13-17 at 02:53 AM ----------
The above chart would have been based on a 60 shutter speed so you would need to halve f stop settiongs for a start then work out your focal lengthd or distances I forget what the mm was about. think it was the distance from the job. but that chart works perfect for that flash. not the 080c pentax.