Originally posted by tuco Looks like a no-go this full moon here. Rain or snow is now in the forecast for the 18th. How many stops you think should be added for heavy cloud cover? Three maybe? The clouds can be so thick here that there might as well be no full moon at all.
You can always shoot many days before and after the full Moon. You can record more star trails in these times when the Moon is less bright. You will need to expose longer of course. Reciprocity failure will be progressive in longer exposures.
I prefer f/8 for the Pentax 67 wide angle lenses (45,55, and 75) as they are very sharp at that aperture and do not vignette, yet offer bright enough images for reasonable exposures. Depth of field is good as well. I sometimes will stop down to F/9.5 or f/11 and recalculate my exposure if I need more depth of field.
At ISO 100 @ F/8
Days before
or after Full ------------------- ISO 100 Film (Acros, Provia, E100)
Full --------------------------- 10-20 Min
1 ------------------------------ 15-30 Min
2 ------------------------------ 20-40 Min
3-4 --------------------------- 25-60 Min
7 * --------------------------- 120 Min +
* First or Last Quarter Moon