Quote Originally Posted by gr82bart
One more question - which f-stop do I use? If the disk has an f-stop of f7.7 and the shutter an f-stop of 5.6, I assume the f5.6 f-stop prevails, right?
Nope, the smaller f/stop is the one that prevails. Think about it for a minute... if the disk has a stop of f/7.7 and the lens is f/5.6, how would the lens get more light than the disk allows?