Why is F6.3 the max? (DMC ZS7)
The other day I was in Denver in the Botanical Garden and wanted to photograph a sculpture of a barracuda in front of a waterfall. Because waterfalls look nicer if photographed with a slow shutter, so that the water looks milky white, I went into manual mode and set the shutter speed to 1/10 of a second. Ouch! The picture came out way overexposed because the highest F-stop on the camera is F6.3. To get a balanced exposure the F would have had to be at about 16 or higher, on this bright sunlit day.
I don't understand this limitation, technically. I know that lens diameter is the outer limit for low F-stops, so it's understandable why a small camera wouldn't be able to open up to F2.8, for example. But higher F stops mean smaller aperture holes, and I don't understand why a small camera can't have a very small aperture, smaller than F 6.3. Can somebody with more engineering moxie than me explain this?